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author | 2006-12-08 11:38:06 +0000 | |
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committer | 2006-12-08 11:38:06 +0000 | |
commit | dc86f6ed17b8e7a702856baefc1d8c3dbd8e229a (patch) | |
tree | c264928fb78e3044f7bf3d8c2eafe2ca607561c4 /DOCS/xml/en/encoding-guide.xml | |
parent | bd007d8968b264bda27028d280c042f3e23178fa (diff) |
General reformatting round:
- fix some " -> "
- reindent with more consistency
- visual markup of <sect?> tags
- break overly long lines
- add missing <replaceable> tags in examples
- cola truck standing by
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@21537 b3059339-0415-0410-9bf9-f77b7e298cf2
Diffstat (limited to 'DOCS/xml/en/encoding-guide.xml')
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1 files changed, 2216 insertions, 2076 deletions
diff --git a/DOCS/xml/en/encoding-guide.xml b/DOCS/xml/en/encoding-guide.xml index c0255a0b2a..eaf954809e 100644 --- a/DOCS/xml/en/encoding-guide.xml +++ b/DOCS/xml/en/encoding-guide.xml @@ -4,82 +4,90 @@ <title>Encoding with <application>MEncoder</application></title> <sect1 id="menc-feat-dvd-mpeg4"> -<title>Making a high quality MPEG-4 ("DivX") rip of a DVD movie</title> +<title>Making a high quality MPEG-4 ("DivX") + rip of a DVD movie</title> <para> - One frequently asked question is "How do I make the highest quality rip for - a given size?". Another question is "How do I make the highest quality DVD - rip possible? I do not care about file size, I just want the best quality." +One frequently asked question is "How do I make the highest quality rip +for a given size?". Another question is "How do I make the highest +quality DVD rip possible? I do not care about file size, I just want the best +quality." </para> <para> - The latter question is perhaps at least somewhat wrongly posed. After all, if - you do not care about file size, why not simply copy the entire MPEG-2 video - stream from the the DVD? Sure, your AVI will end up being 5GB, give - or take, but if you want the best quality and do not care about size, - this is certainly your best option. +The latter question is perhaps at least somewhat wrongly posed. After all, if +you do not care about file size, why not simply copy the entire MPEG-2 video +stream from the the DVD? Sure, your AVI will end up being 5GB, give +or take, but if you want the best quality and do not care about size, +this is certainly your best option. </para> <para> - In fact, the reason you want to transcode a DVD into MPEG-4 is - specifically because you <emphasis role="bold">do</emphasis> care about - file size. +In fact, the reason you want to transcode a DVD into MPEG-4 is +specifically because you <emphasis role="bold">do</emphasis> care about +file size. </para> <para> - It is difficult to offer a cookbook recipe on how to create a very high - quality DVD rip. There are several factors to consider, and you should - understand these details or else you are likely to end up disappointed - with your results. Below we will investigate some of these issues, and - then have a look at an example. We assume you are using - <systemitem class="library">libavcodec</systemitem> to encode the video, - although the theory applies to other codecs as well. +It is difficult to offer a cookbook recipe on how to create a very high +quality DVD rip. There are several factors to consider, and you should +understand these details or else you are likely to end up disappointed +with your results. Below we will investigate some of these issues, and +then have a look at an example. We assume you are using +<systemitem class="library">libavcodec</systemitem> to encode the video, +although the theory applies to other codecs as well. </para> <para> - If this seems to be too much for you, you should probably use one of the - many fine frontends that are listed in the - <ulink url="http://www.mplayerhq.hu/design7/projects.html#mencoder_frontends">MEncoder section</ulink> - of our related projects page. - That way, you should be able to achieve high quality rips without too much - thinking, because most of those tools are designed to take clever decisions - for you. +If this seems to be too much for you, you should probably use one of the +many fine frontends that are listed in the +<ulink url="http://www.mplayerhq.hu/design7/projects.html#mencoder_frontends">MEncoder section</ulink> +of our related projects page. +That way, you should be able to achieve high quality rips without too much +thinking, because most of those tools are designed to take clever decisions +for you. </para> +<!-- ********** --> + <sect2 id="menc-feat-dvd-mpeg4-preparing-encode"> <title>Preparing to encode: Identifying source material and framerate</title> + <para> - Before you even think about encoding a movie, you need to take - several preliminary steps. +Before you even think about encoding a movie, you need to take +several preliminary steps. </para> <para> - The first and most important step before you encode should be - determining what type of content you are dealing with. - If your source material comes from DVD or broadcast/cable/satellite - TV, it will be stored in one of two formats: NTSC for North - America and Japan, PAL for Europe, etc. - It is important to realize, however, that this is just the formatting for - presentation on a television, and often does - <emphasis role="bold">not</emphasis> correspond to the - original format of the movie. - Experience shows that NTSC material is a lot more difficult to encode, - because there more elements to identify in the source. - In order to produce a suitable encode, you need to know the original - format. - Failure to take this into account will result in various flaws in your - encode, including ugly combing (interlacing) artifacts and duplicated - or even lost frames. - Besides being ugly, the artifacts also harm coding efficiency: - You will get worse quality per unit bitrate. +The first and most important step before you encode should be +determining what type of content you are dealing with. +If your source material comes from DVD or broadcast/cable/satellite +TV, it will be stored in one of two formats: NTSC for North +America and Japan, PAL for Europe, etc. +It is important to realize, however, that this is just the formatting for +presentation on a television, and often does +<emphasis role="bold">not</emphasis> correspond to the +original format of the movie. +Experience shows that NTSC material is a lot more difficult to encode, +because there more elements to identify in the source. +In order to produce a suitable encode, you need to know the original +format. +Failure to take this into account will result in various flaws in your +encode, including ugly combing (interlacing) artifacts and duplicated +or even lost frames. +Besides being ugly, the artifacts also harm coding efficiency: +You will get worse quality per unit bitrate. </para> + <sect3 id="menc-feat-dvd-mpeg4-preparing-encode-fps"> <title>Identifying source framerate</title> + <para> - Here is a list of common types of source material, where you are - likely to find them, and their properties: +Here is a list of common types of source material, where you are +likely to find them, and their properties: </para> + <itemizedlist> <listitem><para> <emphasis role="bold">Standard Film</emphasis>: Produced for @@ -122,31 +130,35 @@ </itemizedlist> </sect3> + <sect3 id="menc-feat-dvd-mpeg4-preparing-encode-material"> <title>Identifying source material</title> + <para> - Movies consisting of frames are referred to as progressive, - while those consisting of independent fields are called - either interlaced or video - though this latter term is - ambiguous. +Movies consisting of frames are referred to as progressive, +while those consisting of independent fields are called +either interlaced or video - though this latter term is +ambiguous. </para> + <para> - To further complicate matters, some movies will be a mix of - several of the above. +To further complicate matters, some movies will be a mix of +several of the above. </para> + <para> - The most important distinction to make between all of these - formats is that some are frame-based, while others are - field-based. - <emphasis role="bold">Whenever</emphasis> a movie is prepared - for display on television (including DVD), it is converted to a - field-based format. - The various methods by which this can be done are collectively - referred to as "telecine", of which the infamous NTSC - "3:2 pulldown" is one variety. - Unless the original material was also field-based (and the same - fieldrate), you are getting the movie in a format other than the - original. +The most important distinction to make between all of these +formats is that some are frame-based, while others are +field-based. +<emphasis role="bold">Whenever</emphasis> a movie is prepared +for display on television (including DVD), it is converted to a +field-based format. +The various methods by which this can be done are collectively +referred to as "telecine", of which the infamous NTSC +"3:2 pulldown" is one variety. +Unless the original material was also field-based (and the same +fieldrate), you are getting the movie in a format other than the +original. </para> <itemizedlist> @@ -183,39 +195,41 @@ </itemizedlist> <para> - There are also methods for converting between NTSC and PAL video, - but such topics are beyond the scope of this guide. - If you encounter such a movie and want to encode it, your best - bet is to find a copy in the original format. - Conversion between these two formats is highly destructive and - cannot be reversed cleanly, so your encode will greatly suffer - if it is made from a converted source. -</para> -<para> - When video is stored on DVD, consecutive pairs of fields are - grouped as a frame, even though they are not intended to be shown - at the same moment in time. - The MPEG-2 standard used on DVD and digital TV provides a - way both to encode the original progressive frames and to store - the number of fields for which a frame should be shown in the - header of that frame. - If this method has been used, the movie will often be described - as "soft-telecined", since the process only directs the - DVD player to apply pulldown to the movie rather than altering - the movie itself. - This case is highly preferable since it can easily be reversed - (actually ignored) by the encoder, and since it preserves maximal - quality. - However, many DVD and broadcast production studios do not use - proper encoding techniques but instead produce movies with - "hard telecine", where fields are actually duplicated in the - encoded MPEG-2. -</para> -<para> - The procedures for dealing with these cases will be covered - <link linkend="menc-feat-telecine">later in this guide</link>. - For now, we leave you with some guides to identifying which type - of material you are dealing with: +There are also methods for converting between NTSC and PAL video, +but such topics are beyond the scope of this guide. +If you encounter such a movie and want to encode it, your best +bet is to find a copy in the original format. +Conversion between these two formats is highly destructive and +cannot be reversed cleanly, so your encode will greatly suffer +if it is made from a converted source. +</para> + +<para> +When video is stored on DVD, consecutive pairs of fields are +grouped as a frame, even though they are not intended to be shown +at the same moment in time. +The MPEG-2 standard used on DVD and digital TV provides a +way both to encode the original progressive frames and to store +the number of fields for which a frame should be shown in the +header of that frame. +If this method has been used, the movie will often be described +as "soft-telecined", since the process only directs the +DVD player to apply pulldown to the movie rather than altering +the movie itself. +This case is highly preferable since it can easily be reversed +(actually ignored) by the encoder, and since it preserves maximal +quality. +However, many DVD and broadcast production studios do not use +proper encoding techniques but instead produce movies with +"hard telecine", where fields are actually duplicated in the +encoded MPEG-2. +</para> + +<para> +The procedures for dealing with these cases will be covered +<link linkend="menc-feat-telecine">later in this guide</link>. +For now, we leave you with some guides to identifying which type +of material you are dealing with: </para> <itemizedlist> @@ -232,9 +246,9 @@ "combing" at times, then there are several possibilities. The 24000/1001 fps segments are almost certainly progressive content, "soft telecined", but the 30000/1001 fps parts could be - either hard-telecined 24000/1001 fps content or 60000/1001 fields per second NTSC video. - Use the same guidelines as the following two cases to determine - which. + either hard-telecined 24000/1001 fps content or 60000/1001 fields per second + NTSC video. + Use the same guidelines as the following two cases to determine which. </para></listitem> <listitem><para> If <application>MPlayer</application> never shows the framerate @@ -268,192 +282,194 @@ <application>MPlayer</application> can slow down movie playback with the -speed option or play it frame-by-frame. Try using <option>-speed</option> 0.2 to watch the movie very - slowly or press the "<keycap>.</keycap>" key repeatedly to play one frame at a time - and identify the pattern, if you cannot see it at full speed. + slowly or press the "<keycap>.</keycap>" key repeatedly to play one frame at + a time and identify the pattern, if you cannot see it at full speed. </para> </note> </sect3> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-dvd-mpeg4-2pass"> <title>Constant quantizer vs. multipass</title> <para> - It is possible to encode your movie at a wide range of qualities. - With modern video encoders and a bit of pre-codec compression - (downscaling and denoising), it is possible to achieve very good - quality at 700 MB, for a 90-110 minute widescreen movie. - Furthermore, all but the longest movies can be encoded with near-perfect - quality at 1400 MB. +It is possible to encode your movie at a wide range of qualities. +With modern video encoders and a bit of pre-codec compression +(downscaling and denoising), it is possible to achieve very good +quality at 700 MB, for a 90-110 minute widescreen movie. +Furthermore, all but the longest movies can be encoded with near-perfect +quality at 1400 MB. </para> <para> - There are three approaches to encoding the video: constant bitrate - (CBR), constant quantizer, and multipass (ABR, or average bitrate). +There are three approaches to encoding the video: constant bitrate +(CBR), constant quantizer, and multipass (ABR, or average bitrate). </para> <para> - The complexity of the frames of a movie, and thus the number of bits - required to compress them, can vary greatly from one scene to another. - Modern video encoders can adjust to these needs as they go and vary - the bitrate. - In simple modes such as CBR, however, the encoders do not know the - bitrate needs of future scenes and so cannot exceed the requested - average bitrate for long stretches of time. - More advanced modes, such as multipass encode, can take into account - the statistics from previous passes; this fixes the problem mentioned - above. +The complexity of the frames of a movie, and thus the number of bits +required to compress them, can vary greatly from one scene to another. +Modern video encoders can adjust to these needs as they go and vary +the bitrate. +In simple modes such as CBR, however, the encoders do not know the +bitrate needs of future scenes and so cannot exceed the requested +average bitrate for long stretches of time. +More advanced modes, such as multipass encode, can take into account +the statistics from previous passes; this fixes the problem mentioned +above. </para> <note><title>Note:</title> <para> - Most codecs which support ABR encode only support two pass encode - while some others such as <systemitem class="library">x264</systemitem>, - <systemitem class="library">Xvid</systemitem> - and <systemitem class="library">libavcodec</systemitem> support - multipass, which slightly improves quality at each pass, - yet this improvement is no longer measurable nor noticeable after the - 4th or so pass. - Therefore, in this section, two pass and multipass will be used - interchangeably. +Most codecs which support ABR encode only support two pass encode +while some others such as <systemitem class="library">x264</systemitem>, +<systemitem class="library">Xvid</systemitem> +and <systemitem class="library">libavcodec</systemitem> support +multipass, which slightly improves quality at each pass, +yet this improvement is no longer measurable nor noticeable after the +4th or so pass. +Therefore, in this section, two pass and multipass will be used +interchangeably. </para> </note> <para> - In each of these modes, the video codec (such as - <systemitem class="library">libavcodec</systemitem>) - breaks the video frame into 16x16 pixel macroblocks and then applies a - quantizer to each macroblock. The lower the quantizer, the better the - quality and higher the bitrate. - The method the movie encoder uses to determine - which quantizer to use for a given macroblock varies and is highly - tunable. (This is an extreme over-simplification of the actual - process, but the basic concept is useful to understand.) +In each of these modes, the video codec (such as +<systemitem class="library">libavcodec</systemitem>) +breaks the video frame into 16x16 pixel macroblocks and then applies a +quantizer to each macroblock. The lower the quantizer, the better the +quality and higher the bitrate. +The method the movie encoder uses to determine +which quantizer to use for a given macroblock varies and is highly +tunable. (This is an extreme over-simplification of the actual +process, but the basic concept is useful to understand.) </para> <para> - When you specify a constant bitrate, the video codec will encode the video, - discarding - detail as much as necessary and as little as possible in order to remain - lower than the given bitrate. If you truly do not care about file size, - you could as well use CBR and specify a bitrate of infinity. (In - practice, this means a value high enough so that it poses no limit, like - 10000Kbit.) With no real restriction on bitrate, the result is that - the codec will use the lowest - possible quantizer for each macroblock (as specified by - <option>vqmin</option> for - <systemitem class="library">libavcodec</systemitem>, which is 2 by default). - As soon as you specify a - low enough bitrate that the codec - is forced to use a higher quantizer, then you are almost certainly ruining - the quality of your video. - In order to avoid that, you should probably downscale your video, according - to the method described later on in this guide. - In general, you should avoid CBR altogether if you care about quality. +When you specify a constant bitrate, the video codec will encode the video, +discarding +detail as much as necessary and as little as possible in order to remain +lower than the given bitrate. If you truly do not care about file size, +you could as well use CBR and specify a bitrate of infinity. (In +practice, this means a value high enough so that it poses no limit, like +10000Kbit.) With no real restriction on bitrate, the result is that +the codec will use the lowest +possible quantizer for each macroblock (as specified by +<option>vqmin</option> for +<systemitem class="library">libavcodec</systemitem>, which is 2 by default). +As soon as you specify a +low enough bitrate that the codec +is forced to use a higher quantizer, then you are almost certainly ruining +the quality of your video. +In order to avoid that, you should probably downscale your video, according +to the method described later on in this guide. +In general, you should avoid CBR altogether if you care about quality. </para> <para> - With constant quantizer, the codec uses the same quantizer, as - specified by the <option>vqscale</option> option (for - <systemitem class="library">libavcodec</systemitem>), on every macroblock. - If you want the highest quality rip possible, again ignoring bitrate, - you can use <option>vqscale=2</option>. - This will yield the same bitrate and PSNR (peak signal-to-noise ratio) - as CBR with - <option>vbitrate</option>=infinity and the default <option>vqmin</option> - of 2. +With constant quantizer, the codec uses the same quantizer, as +specified by the <option>vqscale</option> option (for +<systemitem class="library">libavcodec</systemitem>), on every macroblock. +If you want the highest quality rip possible, again ignoring bitrate, +you can use <option>vqscale=2</option>. +This will yield the same bitrate and PSNR (peak signal-to-noise ratio) +as CBR with +<option>vbitrate</option>=infinity and the default <option>vqmin</option> +of 2. </para> <para> - The problem with constant quantizing is that it uses the given quantizer - whether the macroblock needs it or not. That is, it might be possible - to use a higher quantizer on a macroblock without sacrificing visual - quality. Why waste the bits on an unnecessarily low quantizer? Your - CPU has as many cycles as there is time, but there is only so many bits - on your hard disk. +The problem with constant quantizing is that it uses the given quantizer +whether the macroblock needs it or not. That is, it might be possible +to use a higher quantizer on a macroblock without sacrificing visual +quality. Why waste the bits on an unnecessarily low quantizer? Your +CPU has as many cycles as there is time, but there is only so many bits +on your hard disk. </para> <para> - With a two pass encode, the first pass will rip the movie as though it - were CBR, but it will keep a log of properties for each frame. This - data is then used during the second pass in order to make intelligent - decisions about which quantizers to use. During fast action or high - detail scenes, higher quantizers will likely be used, and during - slow moving or low detail scenes, lower quantizers will be used. - Normally, the amount of motion is much more important than the - amount of detail. +With a two pass encode, the first pass will rip the movie as though it +were CBR, but it will keep a log of properties for each frame. This +data is then used during the second pass in order to make intelligent +decisions about which quantizers to use. During fast action or high +detail scenes, higher quantizers will likely be used, and during +slow moving or low detail scenes, lower quantizers will be used. +Normally, the amount of motion is much more important than the +amount of detail. </para> <para> - If you use <option>vqscale=2</option>, then you are wasting bits. If you - use <option>vqscale=3</option>, then you are not getting the highest - quality rip. Suppose you rip a DVD at <option>vqscale=3</option>, and - the result is 1800Kbit. If you do a two pass encode with - <option>vbitrate=1800</option>, the resulting video will have <emphasis - role="bold">higher quality</emphasis> for the - <emphasis role="bold">same bitrate</emphasis>. +If you use <option>vqscale=2</option>, then you are wasting bits. If you +use <option>vqscale=3</option>, then you are not getting the highest +quality rip. Suppose you rip a DVD at <option>vqscale=3</option>, and +the result is 1800Kbit. If you do a two pass encode with +<option>vbitrate=1800</option>, the resulting video will have +<emphasis role="bold">higher quality</emphasis> for the +<emphasis role="bold">same bitrate</emphasis>. </para> <para> - Since you are now convinced that two pass is the way to go, the real - question now is what bitrate to use? The answer is that there is no - single answer. Ideally you want to choose a bitrate that yields the - best balance between quality and file size. This is going to vary - depending on the source video. +Since you are now convinced that two pass is the way to go, the real +question now is what bitrate to use? The answer is that there is no +single answer. Ideally you want to choose a bitrate that yields the +best balance between quality and file size. This is going to vary +depending on the source video. </para> <para> - If size does not matter, a good starting point for a very high quality - rip is about 2000Kbit plus or minus 200Kbit. - For fast action or high detail source video, or if you just have a very - critical eye, you might decide on 2400 or 2600. - For some DVDs, you might not notice a difference at 1400Kbit. It is a - good idea to experiment with scenes at different bitrates to get a feel. +If size does not matter, a good starting point for a very high quality +rip is about 2000Kbit plus or minus 200Kbit. +For fast action or high detail source video, or if you just have a very +critical eye, you might decide on 2400 or 2600. +For some DVDs, you might not notice a difference at 1400Kbit. It is a +good idea to experiment with scenes at different bitrates to get a feel. </para> <para> - If you aim at a certain size, you will have to somehow calculate the bitrate. - But before that, you need to know how much space you should reserve for the - audio track(s), so you should <link linkend="menc-feat-dvd-mpeg4-audio">rip - those</link> first. - You can compute the bitrate with the following equation: - <systemitem>bitrate = (target_size_in_Mbytes - sound_size_in_Mbytes) * - 1024 * 1024 / length_in_secs * 8 / 1000</systemitem> - For instance, to squeeze a two-hour movie onto a 702MB CD, with 60MB - of audio track, the video bitrate will have to be: - <systemitem>(702 - 60) * 1024 * 1024 / (120*60) * 8 / 1000 - = 740kbps</systemitem> +If you aim at a certain size, you will have to somehow calculate the bitrate. +But before that, you need to know how much space you should reserve for the +audio track(s), so you should +<link linkend="menc-feat-dvd-mpeg4-audio">rip those</link> first. +You can compute the bitrate with the following equation: +<systemitem>bitrate = (target_size_in_Mbytes - sound_size_in_Mbytes) * +1024 * 1024 / length_in_secs * 8 / 1000</systemitem> +For instance, to squeeze a two-hour movie onto a 702MB CD, with 60MB +of audio track, the video bitrate will have to be: +<systemitem>(702 - 60) * 1024 * 1024 / (120*60) * 8 / 1000 += 740kbps</systemitem> </para> - </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-constraints"> <title>Constraints for efficient encoding</title> <para> - Due to the nature of MPEG-type compression, there are various - constraints you should follow for maximal quality. - MPEG splits the video up into 16x16 squares called macroblocks, - each composed of 4 8x8 blocks of luma (intensity) information and two - half-resolution 8x8 chroma (color) blocks (one for red-cyan axis and - the other for the blue-yellow axis). - Even if your movie width and height are not multiples of 16, the - encoder will use enough 16x16 macroblocks to cover the whole picture - area, and the extra space will go to waste. - So in the interests of maximizing quality at a fixed filesize, it is - a bad idea to use dimensions that are not multiples of 16. +Due to the nature of MPEG-type compression, there are various +constraints you should follow for maximal quality. +MPEG splits the video up into 16x16 squares called macroblocks, +each composed of 4 8x8 blocks of luma (intensity) information and two +half-resolution 8x8 chroma (color) blocks (one for red-cyan axis and +the other for the blue-yellow axis). +Even if your movie width and height are not multiples of 16, the +encoder will use enough 16x16 macroblocks to cover the whole picture +area, and the extra space will go to waste. +So in the interests of maximizing quality at a fixed filesize, it is +a bad idea to use dimensions that are not multiples of 16. </para> <para> - Most DVDs also have some degree of black borders at the edges. Leaving - these in place will hurt quality <emphasis role="bold">a lot</emphasis> - in several ways. +Most DVDs also have some degree of black borders at the edges. Leaving +these in place will hurt quality <emphasis role="bold">a lot</emphasis> +in several ways. </para> <orderedlist> <listitem> -<para> + <para> MPEG-type compression is also highly dependent on frequency domain transformations, in particular the Discrete Cosine Transform (DCT), which is similar to the Fourier transform. This sort of encoding is @@ -461,33 +477,33 @@ has a hard time with sharp edges. In order to encode them it must use many more bits, or else an artifact known as ringing will appear. -</para> + </para> -<para> + <para> The frequency transform (DCT) takes place separately on each macroblock (actually each block), so this problem only applies when the sharp edge is inside a block. If your black borders begin exactly at multiple-of-16 pixel boundaries, this is not a problem. However, the black borders on DVDs rarely come nicely aligned, so in practice you will always need to crop to avoid this penalty. -</para> + </para> </listitem> </orderedlist> <para> - In addition to frequency domain transforms, MPEG-type compression uses - motion vectors to represent the change from one frame to the next. - Motion vectors naturally work much less efficiently for new content - coming in from the edges of the picture, because it is not present in - the previous frame. As long as the picture extends all the way to the - edge of the encoded region, motion vectors have no problem with - content moving out the edges of the picture. However, in the presence - of black borders, there can be trouble: +In addition to frequency domain transforms, MPEG-type compression uses +motion vectors to represent the change from one frame to the next. +Motion vectors naturally work much less efficiently for new content +coming in from the edges of the picture, because it is not present in +the previous frame. As long as the picture extends all the way to the +edge of the encoded region, motion vectors have no problem with +content moving out the edges of the picture. However, in the presence +of black borders, there can be trouble: </para> <orderedlist continuation="continues"> <listitem> -<para> + <para> For each macroblock, MPEG-type compression stores a vector identifying which part of the previous frame should be copied into this macroblock as a base for predicting the next frame. Only the @@ -499,72 +515,71 @@ motion vector will not be used at all and all the changes in this macroblock will have to be coded explicitly. Either way, encoding efficiency is greatly reduced. -</para> + </para> -<para> + <para> Again, this problem only applies if black borders do not line up on multiple-of-16 boundaries. -</para> + </para> </listitem> <listitem> -<para> + <para> Finally, suppose we have a macroblock in the interior of the picture, and an object is moving into this block from near the edge of the image. MPEG-type coding cannot say "copy the part that is inside the picture but not the black border." So the black border will get copied inside too, and lots of bits will have to be spent encoding the part of the picture that is supposed to be there. -</para> + </para> -<para> + <para> If the picture runs all the way to the edge of the encoded area, MPEG has special optimizations to repeatedly copy the pixels at the edge of the picture when a motion vector comes from outside the encoded area. This feature becomes useless when the movie has black borders. Unlike problems 1 and 2, aligning the borders at multiples of 16 does not help here. -</para> + </para> </listitem> -<listitem> -<para> +<listitem><para> Despite the borders being entirely black and never changing, there is at least a minimal amount of overhead involved in having more macroblocks. -</para> -</listitem> +</para></listitem> </orderedlist> <para> - For all of these reasons, it is recommended to fully crop black - borders. Further, if there is an area of noise/distortion at the edge - of the picture, cropping this will improve encoding efficiency as - well. Videophile purists who want to preserve the original as close as - possible may object to this cropping, but unless you plan to encode at - constant quantizer, the quality you gain from cropping will - considerably exceed the amount of information lost at the edges. +For all of these reasons, it is recommended to fully crop black +borders. Further, if there is an area of noise/distortion at the edge +of the picture, cropping this will improve encoding efficiency as +well. Videophile purists who want to preserve the original as close as +possible may object to this cropping, but unless you plan to encode at +constant quantizer, the quality you gain from cropping will +considerably exceed the amount of information lost at the edges. </para> </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-crop"> <title>Cropping and Scaling</title> <para> - Recall from the previous section that the final picture size you - encode should be a multiple of 16 (in both width and height). - This can be achieved by cropping, scaling, or a combination of both. +Recall from the previous section that the final picture size you +encode should be a multiple of 16 (in both width and height). +This can be achieved by cropping, scaling, or a combination of both. </para> <para> - When cropping, there are a few guidelines that must be followed to - avoid damaging your movie. - The normal YUV format, 4:2:0, stores chroma (color) information - subsampled, i.e. chroma is only sampled half as often in each - direction as luma (intensity) information. - Observe this diagram, where L indicates luma sampling points and C - chroma. +When cropping, there are a few guidelines that must be followed to +avoid damaging your movie. +The normal YUV format, 4:2:0, stores chroma (color) information +subsampled, i.e. chroma is only sampled half as often in each +direction as luma (intensity) information. +Observe this diagram, where L indicates luma sampling points and C +chroma. </para> <informaltable> @@ -641,18 +656,18 @@ </informaltable> <para> - As you can see, rows and columns of the image naturally come in pairs. - Thus your crop offsets and dimensions <emphasis>must</emphasis> be - even numbers. - If they are not, the chroma will no longer line up correctly with the - luma. - In theory, it is possible to crop with odd offsets, but it requires - resampling the chroma which is potentially a lossy operation and not - supported by the crop filter. +As you can see, rows and columns of the image naturally come in pairs. +Thus your crop offsets and dimensions <emphasis>must</emphasis> be +even numbers. +If they are not, the chroma will no longer line up correctly with the +luma. +In theory, it is possible to crop with odd offsets, but it requires +resampling the chroma which is potentially a lossy operation and not +supported by the crop filter. </para> <para> - Further, interlaced video is sampled as follows: +Further, interlaced video is sampled as follows: </para> <informaltable> @@ -893,164 +908,169 @@ </informaltable> <para> - As you can see, the pattern does not repeat until after 4 lines. - So for interlaced video, your y-offset and height for cropping must - be multiples of 4. +As you can see, the pattern does not repeat until after 4 lines. +So for interlaced video, your y-offset and height for cropping must +be multiples of 4. </para> <para> - Native DVD resolution is 720x480 for NTSC, and 720x576 for PAL, but - there is an aspect flag that specifies whether it is full-screen (4:3) or - wide-screen (16:9). Many (if not most) widescreen DVDs are not strictly - 16:9, and will be either 1.85:1 or 2.35:1 (cinescope). This means that - there will be black bands in the video that will need to be cropped out. +Native DVD resolution is 720x480 for NTSC, and 720x576 for PAL, but +there is an aspect flag that specifies whether it is full-screen (4:3) or +wide-screen (16:9). Many (if not most) widescreen DVDs are not strictly +16:9, and will be either 1.85:1 or 2.35:1 (cinescope). This means that +there will be black bands in the video that will need to be cropped out. </para> <para> - <application>MPlayer</application> provides a crop detection filter that - will determine the crop rectangle (<option>-vf cropdetect</option>). - Run <application>MPlayer</application> with - <option>-vf cropdetect</option> and it will print out the crop - settings to remove the borders. - You should let the movie run long enough that the whole picture - area is used, in order to get accurate crop values. +<application>MPlayer</application> provides a crop detection filter that +will determine the crop rectangle (<option>-vf cropdetect</option>). +Run <application>MPlayer</application> with +<option>-vf cropdetect</option> and it will print out the crop +settings to remove the borders. +You should let the movie run long enough that the whole picture +area is used, in order to get accurate crop values. </para> <para> - Then, test the values you get with <application>MPlayer</application>, - using the command line which was printed by - <option>cropdetect</option>, and adjust the rectangle as needed. - The <option>rectangle</option> filter can help by allowing you to - interactively position the crop rectangle over your movie. - Remember to follow the above divisibility guidelines so that you - do not misalign the chroma planes. +Then, test the values you get with <application>MPlayer</application>, +using the command line which was printed by +<option>cropdetect</option>, and adjust the rectangle as needed. +The <option>rectangle</option> filter can help by allowing you to +interactively position the crop rectangle over your movie. +Remember to follow the above divisibility guidelines so that you +do not misalign the chroma planes. </para> <para> - In certain cases, scaling may be undesirable. - Scaling in the vertical direction is difficult with interlaced - video, and if you wish to preserve the interlacing, you should - usually refrain from scaling. - If you will not be scaling but you still want to use multiple-of-16 - dimensions, you will have to overcrop. - Do not undercrop, since black borders are very bad for encoding! +In certain cases, scaling may be undesirable. +Scaling in the vertical direction is difficult with interlaced +video, and if you wish to preserve the interlacing, you should +usually refrain from scaling. +If you will not be scaling but you still want to use multiple-of-16 +dimensions, you will have to overcrop. +Do not undercrop, since black borders are very bad for encoding! </para> <para> - Because MPEG-4 uses 16x16 macroblocks, you will want to make sure that each - dimension of the video you are encoding is a multiple of 16 or else you - will be degrading quality, especially at lower bitrates. You can do this - by rounding the width and height of the crop rectangle down to the nearest - multiple of 16. - As stated earlier, when cropping, you will want to increase the Y offset by - half the difference of the old and the new height so that the resulting - video is taken from the center of the frame. And because of the way DVD - video is sampled, make sure the offset is an even number. (In fact, as a - rule, never use odd values for any parameter when you are cropping and - scaling video.) If you are not comfortable throwing a few extra pixels - away, you might prefer instead to scale the video instead. We will look - at this in our example below. - You can actually let the <option>cropdetect</option> filter do all of the - above for you, as it has an optional <option>round</option> parameter that - is equal to 16 by default. +Because MPEG-4 uses 16x16 macroblocks, you will want to make sure that each +dimension of the video you are encoding is a multiple of 16 or else you +will be degrading quality, especially at lower bitrates. You can do this +by rounding the width and height of the crop rectangle down to the nearest +multiple of 16. +As stated earlier, when cropping, you will want to increase the Y offset by +half the difference of the old and the new height so that the resulting +video is taken from the center of the frame. And because of the way DVD +video is sampled, make sure the offset is an even number. (In fact, as a +rule, never use odd values for any parameter when you are cropping and +scaling video.) If you are not comfortable throwing a few extra pixels +away, you might prefer instead to scale the video instead. We will look +at this in our example below. +You can actually let the <option>cropdetect</option> filter do all of the +above for you, as it has an optional <option>round</option> parameter that +is equal to 16 by default. </para> <para> - Also, be careful about "half black" pixels at the edges. Make sure you - crop these out too, or else you will be wasting bits there that - are better spent elsewhere. +Also, be careful about "half black" pixels at the edges. Make sure you +crop these out too, or else you will be wasting bits there that +are better spent elsewhere. </para> <para> - After all is said and done, you will probably end up with video whose pixels - are not quite 1.85:1 or 2.35:1, but rather something close to that. You - could calculate the new aspect ratio manually, but - <application>MEncoder</application> offers an option for <systemitem - class="library">libavcodec</systemitem> called <option>autoaspect</option> - that will do this for you. Absolutely do not scale this video up in order to - square the pixels unless you like to waste your hard disk space. Scaling - should be done on playback, and the player will use the aspect stored in - the AVI to determine the correct resolution. - Unfortunately, not all players enforce this auto-scaling information, - therefore you may still want to rescale. +After all is said and done, you will probably end up with video whose pixels +are not quite 1.85:1 or 2.35:1, but rather something close to that. You +could calculate the new aspect ratio manually, but +<application>MEncoder</application> offers an option for <systemitem +class="library">libavcodec</systemitem> called <option>autoaspect</option> +that will do this for you. Absolutely do not scale this video up in order to +square the pixels unless you like to waste your hard disk space. Scaling +should be done on playback, and the player will use the aspect stored in +the AVI to determine the correct resolution. +Unfortunately, not all players enforce this auto-scaling information, +therefore you may still want to rescale. </para> </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-resolution-bitrate"> <title>Choosing resolution and bitrate</title> <para> - If you will not be encoding in constant quantizer mode, you need to - select a bitrate. - The concept of bitrate is quite simple. - It is the (average) number of bits that will be consumed to store your - movie, per second. - Normally bitrate is measured in kilobits (1000 bits) per second. - The size of your movie on disk is the bitrate times the length of the - movie in time, plus a small amount of "overhead" (see the section on - <link linkend="menc-feat-dvd-mpeg4-muxing-avi-limitations">the AVI container</link> - for instance). - Other parameters such as scaling, cropping, etc. will - <emphasis role="bold">not</emphasis> alter the file size unless you - change the bitrate as well!. -</para> -<para> - Bitrate does <emphasis role="bold">not</emphasis> scale proportionally - to resolution. - That is to say, a 320x240 file at 200 kbit/sec will not be the same - quality as the same movie at 640x480 and 800 kbit/sec! - There are two reasons for this: +If you will not be encoding in constant quantizer mode, you need to +select a bitrate. +The concept of bitrate is quite simple. +It is the (average) number of bits that will be consumed to store your +movie, per second. +Normally bitrate is measured in kilobits (1000 bits) per second. +The size of your movie on disk is the bitrate times the length of the +movie in time, plus a small amount of "overhead" (see the section on +<link linkend="menc-feat-dvd-mpeg4-muxing-avi-limitations">the AVI container</link> +for instance). +Other parameters such as scaling, cropping, etc. will +<emphasis role="bold">not</emphasis> alter the file size unless you +change the bitrate as well!. +</para> + +<para> +Bitrate does <emphasis role="bold">not</emphasis> scale proportionally +to resolution. +That is to say, a 320x240 file at 200 kbit/sec will not be the same +quality as the same movie at 640x480 and 800 kbit/sec! +There are two reasons for this: <orderedlist> - <listitem><para> - <emphasis role="bold">Perceptual</emphasis>: You notice MPEG - artifacts more if they are scaled up bigger! - Artifacts appear on the scale of blocks (8x8). - Your eye will not see errors in 4800 small blocks as easily as it - sees errors in 1200 large blocks (assuming you will be scaling both - to fullscreen). - </para></listitem> - <listitem><para> - <emphasis role="bold">Theoretical</emphasis>: When you scale down - an image but still use the same size (8x8) blocks for the frequency - space transform, you move more data to the high frequency bands. - Roughly speaking, each pixel contains more of the detail than it - did before. - So even though your scaled-down picture contains 1/4 the information - in the spacial directions, it could still contain a large portion - of the information in the frequency domain (assuming that the high - frequencies were underutilized in the original 640x480 image). - </para></listitem> - </orderedlist> -</para> -<para> - Past guides have recommended choosing a bitrate and resolution based - on a "bits per pixel" approach, but this is usually not valid due to - the above reasons. - A better estimate seems to be that bitrates scale proportional to the - square root of resolution, so that 320x240 and 400 kbit/sec would be - comparable to 640x480 at 800 kbit/sec. - However this has not been verified with theoretical or empirical - rigor. - Further, given that movies vary greatly with regard to noise, detail, - degree of motion, etc., it is futile to make general recommendations - for bits per length-of-diagonal (the analog of bits per pixel, - using the square root). -</para> -<para> - So far we have discussed the difficulty of choosing a bitrate and - resolution. +<listitem><para> + <emphasis role="bold">Perceptual</emphasis>: You notice MPEG + artifacts more if they are scaled up bigger! + Artifacts appear on the scale of blocks (8x8). + Your eye will not see errors in 4800 small blocks as easily as it + sees errors in 1200 large blocks (assuming you will be scaling both + to fullscreen). +</para></listitem> +<listitem><para> + <emphasis role="bold">Theoretical</emphasis>: When you scale down + an image but still use the same size (8x8) blocks for the frequency + space transform, you move more data to the high frequency bands. + Roughly speaking, each pixel contains more of the detail than it + did before. + So even though your scaled-down picture contains 1/4 the information + in the spacial directions, it could still contain a large portion + of the information in the frequency domain (assuming that the high + frequencies were underutilized in the original 640x480 image). +</para></listitem> +</orderedlist> +</para> + +<para> +Past guides have recommended choosing a bitrate and resolution based +on a "bits per pixel" approach, but this is usually not valid due to +the above reasons. +A better estimate seems to be that bitrates scale proportional to the +square root of resolution, so that 320x240 and 400 kbit/sec would be +comparable to 640x480 at 800 kbit/sec. +However this has not been verified with theoretical or empirical +rigor. +Further, given that movies vary greatly with regard to noise, detail, +degree of motion, etc., it is futile to make general recommendations +for bits per length-of-diagonal (the analog of bits per pixel, +using the square root). +</para> +<para> +So far we have discussed the difficulty of choosing a bitrate and +resolution. </para> <sect3 id="menc-feat-dvd-mpeg4-resolution-bitrate-compute"> <title>Computing the resolution</title> + <para> - The following steps will guide you in computing the resolution of your - encode without distorting the video too much, by taking into account several - types of information about the source video. - First, you should compute the encoded aspect ratio: - <systemitem>ARc = (Wc x (ARa / PRdvd )) / Hc</systemitem> +The following steps will guide you in computing the resolution of your +encode without distorting the video too much, by taking into account several +types of information about the source video. +First, you should compute the encoded aspect ratio: +<systemitem>ARc = (Wc x (ARa / PRdvd )) / Hc</systemitem> + <itemizedlist> <title>where:</title> <listitem><para> @@ -1067,219 +1087,220 @@ </para> <para> - Then, you can compute the X and Y resolution, according to a certain - Compression Quality (CQ) factor: - <systemitem>ResY = INT(SQRT( 1000*Bitrate/25/ARc/CQ )/16) * 16</systemitem> - and - <systemitem>ResX = INT( ResY * ARc / 16) * 16</systemitem> +Then, you can compute the X and Y resolution, according to a certain +Compression Quality (CQ) factor: +<systemitem>ResY = INT(SQRT( 1000*Bitrate/25/ARc/CQ )/16) * 16</systemitem> +and +<systemitem>ResX = INT( ResY * ARc / 16) * 16</systemitem> </para> <para> - Okay, but what is the CQ? - The CQ represents the number of bits per pixel and per frame of the encode. - Roughly speaking, the greater the CQ, the less the likelihood to see - encoding artifacts. - However, if you have a target size for your movie (1 or 2 CDs for instance), - there is a limited total number of bits that you can spend; therefore it is - necessary to find a good tradeoff between compressibility and quality. +Okay, but what is the CQ? +The CQ represents the number of bits per pixel and per frame of the encode. +Roughly speaking, the greater the CQ, the less the likelihood to see +encoding artifacts. +However, if you have a target size for your movie (1 or 2 CDs for instance), +there is a limited total number of bits that you can spend; therefore it is +necessary to find a good tradeoff between compressibility and quality. </para> <para> - The CQ depends on the bitrate, the video codec efficiency and the - movie resolution. - In order to raise the CQ, typically you would downscale the movie given that the - bitrate is computed in function of the target size and the length of the - movie, which are constant. - With MPEG-4 ASP codecs such as <systemitem class="library">Xvid</systemitem> - and <systemitem class="library">libavcodec</systemitem>, a CQ below 0.18 - usually results in a pretty blocky picture, because there - are not enough bits to code the information of each macroblock. (MPEG4, like - many other codecs, groups pixels by blocks of several pixels to compress the - image; if there are not enough bits, the edges of those blocks are - visible.) - It is therefore wise to take a CQ ranging from 0.20 to 0.22 for a 1 CD rip, - and 0.26-0.28 for 2 CDs rip with standard encoding options. - More advanced encoding options such as those listed here for - <link linkend="menc-feat-mpeg4-lavc-example-settings"><systemitem class="library">libavcodec</systemitem></link> - and +The CQ depends on the bitrate, the video codec efficiency and the +movie resolution. +In order to raise the CQ, typically you would downscale the movie given that the +bitrate is computed in function of the target size and the length of the +movie, which are constant. +With MPEG-4 ASP codecs such as <systemitem class="library">Xvid</systemitem> +and <systemitem class="library">libavcodec</systemitem>, a CQ below 0.18 +usually results in a pretty blocky picture, because there +are not enough bits to code the information of each macroblock. (MPEG4, like +many other codecs, groups pixels by blocks of several pixels to compress the +image; if there are not enough bits, the edges of those blocks are +visible.) +It is therefore wise to take a CQ ranging from 0.20 to 0.22 for a 1 CD rip, +and 0.26-0.28 for 2 CDs rip with standard encoding options. +More advanced encoding options such as those listed here for +<link linkend="menc-feat-mpeg4-lavc-example-settings"><systemitem class="library">libavcodec</systemitem></link> +and <link linkend="menc-feat-xvid-example-settings"><systemitem class="library">Xvid</systemitem></link> - should make it possible to get the same quality with CQ ranging from - 0.18 to 0.20 for a 1 CD rip, and 0.24 to 0.26 for a 2 CD rip. - With MPEG-4 ASP codecs such as <systemitem class="library">x264</systemitem>, - you can use a CQ ranging from 0.14 to 0.16 with standard encoding options, - and should be able to go as low as 0.10 to 0.12 with - <link linkend="menc-feat-x264-example-settings"><systemitem class="library">x264</systemitem>'s advanced encoding settings</link>. +should make it possible to get the same quality with CQ ranging from +0.18 to 0.20 for a 1 CD rip, and 0.24 to 0.26 for a 2 CD rip. +With MPEG-4 ASP codecs such as <systemitem class="library">x264</systemitem>, +you can use a CQ ranging from 0.14 to 0.16 with standard encoding options, +and should be able to go as low as 0.10 to 0.12 with +<link linkend="menc-feat-x264-example-settings"><systemitem class="library">x264</systemitem>'s advanced encoding settings</link>. </para> <para> - Please take note that the CQ is just an indicative figure, as depending on - the encoded content, a CQ of 0.18 may look just fine for a Bergman, contrary - to a movie such as The Matrix, which contains many high-motion scenes. - On the other hand, it is worthless to raise CQ higher than 0.30 as you would - be wasting bits without any noticeable quality gain. - Also note that as mentioned earlier in this guide, low resolution videos - need a bigger CQ (compared to, for instance, DVD resolution) to look good. +Please take note that the CQ is just an indicative figure, as depending on +the encoded content, a CQ of 0.18 may look just fine for a Bergman, contrary +to a movie such as The Matrix, which contains many high-motion scenes. +On the other hand, it is worthless to raise CQ higher than 0.30 as you would +be wasting bits without any noticeable quality gain. +Also note that as mentioned earlier in this guide, low resolution videos +need a bigger CQ (compared to, for instance, DVD resolution) to look good. </para> </sect3> - </sect2> +<!-- ********** --> + <sect2 id="menc-feat-dvd-mpeg4-filtering"> <title>Filtering</title> <para> - Learning how to use <application>MEncoder</application>'s video filters - is essential to producing good encodes. - All video processing is performed through the filters -- cropping, - scaling, color adjustment, noise removal, sharpening, deinterlacing, - telecine, inverse telecine, and deblocking, just to name a few. - Along with the vast number of supported input formats, the variety of - filters available in <application>MEncoder</application> is one of its - main advantages over other similar programs. +Learning how to use <application>MEncoder</application>'s video filters +is essential to producing good encodes. +All video processing is performed through the filters -- cropping, +scaling, color adjustment, noise removal, sharpening, deinterlacing, +telecine, inverse telecine, and deblocking, just to name a few. +Along with the vast number of supported input formats, the variety of +filters available in <application>MEncoder</application> is one of its +main advantages over other similar programs. </para> <para> - Filters are loaded in a chain using the -vf option: +Filters are loaded in a chain using the -vf option: - <screen>-vf filter1=options,filter2=options,...</screen> +<screen>-vf filter1=options,filter2=options,...</screen> - Most filters take several numeric options separated by colons, but - the syntax for options varies from filter to filter, so read the man - page for details on the filters you wish to use. +Most filters take several numeric options separated by colons, but +the syntax for options varies from filter to filter, so read the man +page for details on the filters you wish to use. </para> <para> - Filters operate on the video in the order they are loaded. - For example, the following chain: +Filters operate on the video in the order they are loaded. +For example, the following chain: - <screen>-vf crop=688:464:12:4,scale=640:464</screen> +<screen>-vf crop=688:464:12:4,scale=640:464</screen> - will first crop the 688x464 region of the picture with upper-left - corner at (12,4), and then scale the result down to 640x464. +will first crop the 688x464 region of the picture with upper-left +corner at (12,4), and then scale the result down to 640x464. </para> <para> - Certain filters need to be loaded at or near the beginning of the - filter chain, in order to take advantage of information from the - video decoder that will be lost or invalidated by other filters. - The principal examples are <option>pp</option> (postprocessing, only - when it is performing deblock or dering operations), - <option>spp</option> (another postprocessor to remove MPEG artifacts), - <option>pullup</option> (inverse telecine), and - <option>softpulldown</option> (for converting soft telecine to hard - telecine). +Certain filters need to be loaded at or near the beginning of the +filter chain, in order to take advantage of information from the +video decoder that will be lost or invalidated by other filters. +The principal examples are <option>pp</option> (postprocessing, only +when it is performing deblock or dering operations), +<option>spp</option> (another postprocessor to remove MPEG artifacts), +<option>pullup</option> (inverse telecine), and +<option>softpulldown</option> (for converting soft telecine to hard telecine). </para> <para> - In general, you want to do as little filtering as possible to the movie - in order to remain close to the original DVD source. Cropping is often - necessary (as described above), but avoid to scale the video. Although - scaling down is sometimes preferred to using higher quantizers, we want - to avoid both these things: remember that we decided from the start to - trade bits for quality. +In general, you want to do as little filtering as possible to the movie +in order to remain close to the original DVD source. Cropping is often +necessary (as described above), but avoid to scale the video. Although +scaling down is sometimes preferred to using higher quantizers, we want +to avoid both these things: remember that we decided from the start to +trade bits for quality. </para> <para> - Also, do not adjust gamma, contrast, brightness, etc. What looks good - on your display may not look good on others. These adjustments should - be done on playback only. +Also, do not adjust gamma, contrast, brightness, etc. What looks good +on your display may not look good on others. These adjustments should +be done on playback only. </para> <para> - One thing you might want to do, however, is pass the video through a - very light denoise filter, such as <option>-vf hqdn3d=2:1:2</option>. - Again, it is a matter of putting those bits to better use: why waste them - encoding noise when you can just add that noise back in during playback? - Increasing the parameters for <option>hqdn3d</option> will further - improve compressibility, but if you increase the values too much, you - risk degrading the image visibily. The suggested values above - (<option>2:1:2</option>) are quite conservative; you should feel free to - experiment with higher values and observe the results for yourself. +One thing you might want to do, however, is pass the video through a +very light denoise filter, such as <option>-vf hqdn3d=2:1:2</option>. +Again, it is a matter of putting those bits to better use: why waste them +encoding noise when you can just add that noise back in during playback? +Increasing the parameters for <option>hqdn3d</option> will further +improve compressibility, but if you increase the values too much, you +risk degrading the image visibily. The suggested values above +(<option>2:1:2</option>) are quite conservative; you should feel free to +experiment with higher values and observe the results for yourself. </para> - </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-interlacing"> <title>Interlacing and Telecine</title> <para> - Almost all movies are shot at 24 fps. Because NTSC is 30000/1001 fps, some - processing must be done to this 24 fps video to make it run at the correct - NTSC framerate. The process is called 3:2 pulldown, commonly referred to - as telecine (because pulldown is often applied during the telecine - process), and, naively described, it works by slowing the film down to - 24000/1001 fps, and repeating every fourth frame. +Almost all movies are shot at 24 fps. Because NTSC is 30000/1001 fps, some +processing must be done to this 24 fps video to make it run at the correct +NTSC framerate. The process is called 3:2 pulldown, commonly referred to +as telecine (because pulldown is often applied during the telecine +process), and, naively described, it works by slowing the film down to +24000/1001 fps, and repeating every fourth frame. </para> <para> - No special processing, however, is done to the video for PAL DVDs, which - run at 25 fps. (Technically, PAL can be telecined, called 2:2 pulldown, - but this does not become an issue in practice.) The 24 fps film is simply - played back at 25 fps. The result is that the movie runs slightly faster, - but unless you are an alien, you probably will not notice the difference. - Most PAL DVDs have pitch-corrected audio, so when they are played back at - 25 fps things will sound right, even though the audio track (and hence the - whole movie) has a running time that is 4% less than NTSC DVDs. +No special processing, however, is done to the video for PAL DVDs, which +run at 25 fps. (Technically, PAL can be telecined, called 2:2 pulldown, +but this does not become an issue in practice.) The 24 fps film is simply +played back at 25 fps. The result is that the movie runs slightly faster, +but unless you are an alien, you probably will not notice the difference. +Most PAL DVDs have pitch-corrected audio, so when they are played back at +25 fps things will sound right, even though the audio track (and hence the +whole movie) has a running time that is 4% less than NTSC DVDs. </para> <para> - Because the video in a PAL DVD has not been altered, you need not worry - much about framerate. The source is 25 fps, and your rip will be 25 - fps. However, if you are ripping an NTSC DVD movie, you may need to - apply inverse telecine. +Because the video in a PAL DVD has not been altered, you need not worry +much about framerate. The source is 25 fps, and your rip will be 25 +fps. However, if you are ripping an NTSC DVD movie, you may need to +apply inverse telecine. </para> <para> - For movies shot at 24 fps, the video on the NTSC DVD is either telecined - 30000/1001, or else it is progressive 24000/1001 fps and intended to be telecined - on-the-fly by a DVD player. On the other hand, TV series are usually - only interlaced, not telecined. This is not a hard rule: some TV series - are interlaced (such as Buffy the Vampire Slayer) whereas some are a - mixture of progressive and interlaced (such as Angel, or 24). +For movies shot at 24 fps, the video on the NTSC DVD is either telecined +30000/1001, or else it is progressive 24000/1001 fps and intended to be +telecined on-the-fly by a DVD player. On the other hand, TV series are usually +only interlaced, not telecined. This is not a hard rule: some TV series +are interlaced (such as Buffy the Vampire Slayer) whereas some are a +mixture of progressive and interlaced (such as Angel, or 24). </para> <para> - It is highly recommended that you read the section on - <link linkend="menc-feat-telecine">How to deal with telecine and interlacing in NTSC DVDs</link> - to learn how to handle the different possibilities. +It is highly recommended that you read the section on +<link linkend="menc-feat-telecine">How to deal with telecine and interlacing in NTSC DVDs</link> +to learn how to handle the different possibilities. </para> <para> - However, if you are mostly just ripping movies, likely you are either - dealing with 24 fps progressive or telecined video, in which case you can - use the <option>pullup</option> filter <option>-vf - pullup,softskip</option>. +However, if you are mostly just ripping movies, likely you are either +dealing with 24 fps progressive or telecined video, in which case you can +use the <option>pullup</option> filter <option>-vf +pullup,softskip</option>. </para> - </sect2> +<!-- ********** --> + <sect2 id="menc-feat-dvd-mpeg4-encoding-interlaced"> <title>Encoding interlaced video</title> <para> - If the movie you want to encode is interlaced (NTSC video or - PAL video), you will need to choose whether you want to - deinterlace or not. - While deinterlacing will make your movie usable on progressive - scan displays such a computer monitors and projectors, it comes - at a cost: The fieldrate of 50 or 60000/1001 fields per second - is halved to 25 or 30000/1001 frames per second, and roughly half of - the information in your movie will be lost during scenes with - significant motion. +If the movie you want to encode is interlaced (NTSC video or +PAL video), you will need to choose whether you want to +deinterlace or not. +While deinterlacing will make your movie usable on progressive +scan displays such a computer monitors and projectors, it comes +at a cost: The fieldrate of 50 or 60000/1001 fields per second +is halved to 25 or 30000/1001 frames per second, and roughly half of +the information in your movie will be lost during scenes with +significant motion. </para> <para> - Therefore, if you are encoding for high quality archival purposes, - it is recommended not to deinterlace. - You can always deinterlace the movie at playback time when - displaying it on progressive scan devices. - The power of currently available computers forces players to use a - deinterlacing filter, which results in a slight degradation in - image quality. - But future players will be able to mimic the interlaced display of - a TV, deinterlacing to full fieldrate and interpolating 50 or - 60000/1001 entire frames per second from the interlaced video. +Therefore, if you are encoding for high quality archival purposes, +it is recommended not to deinterlace. +You can always deinterlace the movie at playback time when +displaying it on progressive scan devices. +The power of currently available computers forces players to use a +deinterlacing filter, which results in a slight degradation in +image quality. +But future players will be able to mimic the interlaced display of +a TV, deinterlacing to full fieldrate and interpolating 50 or +60000/1001 entire frames per second from the interlaced video. </para> <para> @@ -1302,19 +1323,19 @@ Special care must be taken when working with interlaced video: <para> With these things in mind, here is our first example: -</para> <screen> - mencoder <replaceable>capture.avi</replaceable> -mc 0 -oac lavc -ovc lavc -lavcopts \ - vcodec=mpeg2video:vbitrate=6000:ilme:ildct:acodec=mp2:abitrate=224 +mencoder <replaceable>capture.avi</replaceable> -mc 0 -oac lavc -ovc lavc -lavcopts \ + vcodec=mpeg2video:vbitrate=6000:ilme:ildct:acodec=mp2:abitrate=224 </screen> -<para> Note the <option>ilme</option> and <option>ildct</option> options. </para> </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-av-sync"> <title>Notes on Audio/Video synchronization</title> + <para> <application>MEncoder</application>'s audio/video synchronization algorithms were designed with the intention of recovering files with @@ -1329,6 +1350,7 @@ the <option>-mc 0</option> option, or put this in your you are only working with good sources (DVD, TV capture, high quality MPEG-4 rips, etc) and not broken ASF/RM/MOV files. </para> + <para> If you want to further guard against strange frame skips and duplication, you can use both <option>-mc 0</option> and @@ -1339,9 +1361,11 @@ unpredictably add or drop frames, or if your input file has variable framerate! Therefore, using <option>-noskip</option> is not in general recommended. </para> + <para> -The so-called "three-pass" audio encoding which <application>MEncoder</application> -supports has been reported to cause A/V desync. +The so-called "three-pass" audio encoding which +<application>MEncoder</application> supports has been reported to cause A/V +desync. This will definitely happen if it is used in conjunction with certain filters, therefore, it is now recommended <emphasis>not</emphasis> to use three-pass audio mode. @@ -1350,6 +1374,7 @@ users who understand when it is safe to use and when it is not. If you have never heard of three-pass mode before, forget that we even mentioned it! </para> + <para> There have also been reports of A/V desync when encoding from stdin with <application>MEncoder</application>. @@ -1357,23 +1382,26 @@ Do not do this! Always use a file or CD/DVD/etc device as input. </para> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-dvd-mpeg4-codec"> <title>Choosing the video codec</title> <para> - Which video codec is best to choose depends on several factors, - like size, quality, streamability, usability and popularity, some of - which widely depend on personal taste and technical constraints. +Which video codec is best to choose depends on several factors, +like size, quality, streamability, usability and popularity, some of +which widely depend on personal taste and technical constraints. </para> <itemizedlist> - <listitem><para> +<listitem> + <para> <emphasis role="bold">Compression efficiency</emphasis>: It is quite easy to understand that most newer-generation codecs are made to increase quality and compression. Therefore, the authors of this guide and many other people suggest that you cannot go wrong - <footnote id='fn-menc-feat-dvd-mpeg4-codec-cpu'> - <para>Be careful, however: Decoding DVD-resolution MPEG-4 AVC videos + <footnote id='fn-menc-feat-dvd-mpeg4-codec-cpu'><para> + Be careful, however: Decoding DVD-resolution MPEG-4 AVC videos requires a fast machine (i.e. a Pentium 4 over 1.5GHz or a Pentium M over 1GHz). </para></footnote> @@ -1387,18 +1415,21 @@ Do not do this! Always use a file or CD/DVD/etc device as input. Likewise, you should get better quality using MPEG-4 ASP than you would with MPEG-2 codecs. </para> + <para> However, newer codecs which are in heavy development can suffer from bugs which have not yet been noticed and which can ruin an encode. This is simply the tradeoff for using bleeding-edge technology. </para> + <para> What is more, beginning to use a new codec requires that you spend some time becoming familiar with its options, so that you know what to adjust to achieve a desired picture quality. - </para></listitem> + </para> +</listitem> - <listitem><para> +<listitem><para> <emphasis role="bold">Hardware compatibility</emphasis>: It usually takes a long time for standalone video players to begin to include support for the latest video codecs. @@ -1409,9 +1440,10 @@ Do not do this! Always use a file or CD/DVD/etc device as input. (Beware: Usually, not all MPEG-4 ASP features are supported). Please refer to the technical specs of your player (if they are available), or google around for more information. - </para></listitem> +</para></listitem> - <listitem><para> +<listitem> + <para> <emphasis role="bold">Best quality per encoding time</emphasis>: Codecs that have been around for some time (such as <systemitem class="library">libavcodec</systemitem> MPEG-4 and @@ -1421,11 +1453,13 @@ Do not do this! Always use a file or CD/DVD/etc device as input. However, they may have some very advanced options that, if enabled, will make the encode really slow for marginal gains. </para> + <para> If you are after blazing speed you should stick around the default settings of the video codec (although you should still try the other options which are mentioned in other sections of this guide). </para> + <para> You may also consider choosing a codec which can do multi-threaded processing, though this is only useful for users of machines with @@ -1440,9 +1474,11 @@ Do not do this! Always use a file or CD/DVD/etc device as input. <systemitem class="library">x264</systemitem> also allows multi-threaded encoding, which currently speeds up encoding by 15-30% (depending on the encoding settings) while lowering PSNR by about 0.05dB. - </para></listitem> + </para> +</listitem> - <listitem><para> +<listitem> + <para> <emphasis role="bold">Personal taste</emphasis>: This is where it gets almost irrational: For the same reason that some hung on to DivX 3 for years when newer codecs were already doing wonders, @@ -1457,224 +1493,238 @@ Do not do this! Always use a file or CD/DVD/etc device as input. encoding options and codecs to find one that suits you best. The best codec is the one you master, and the one that looks best to your eyes on your display - <footnote id='fn-menc-feat-dvd-mpeg4-codec-playback'> - <para>The same encode may not look the same on someone else's monitor or + <footnote id='fn-menc-feat-dvd-mpeg4-codec-playback'><para> + The same encode may not look the same on someone else's monitor or when played back by a different decoder, so future-proof your encodes by - playing them back on different setups.</para></footnote>! - </para></listitem> + playing them back on different setups. + </para></footnote>! + </para> +</listitem> </itemizedlist> + <para> - Please refer to the section - <link linkend="menc-feat-selecting-codec">selecting codecs and container formats</link> - to get a list of supported codecs. +Please refer to the section +<link linkend="menc-feat-selecting-codec">selecting codecs and container formats</link> +to get a list of supported codecs. </para> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-dvd-mpeg4-audio"> <title>Audio</title> <para> - Audio is a much simpler problem to solve: if you care about quality, just - leave it as is. - Even AC3 5.1 streams are at most 448Kbit/s, and they are worth every bit. - You might be tempted to transcode the audio to high quality Vorbis, but - just because you do not have an A/V receiver for AC3 pass-through today - does not mean you will not have one tomorrow. Future-proof your DVD rips by - preserving the AC3 stream. - You can keep the AC3 stream either by copying it directly into the video - stream <link linkend="menc-feat-mpeg4">during the encoding</link>. - You can also extract the AC3 stream in order to mux it into containers such - as NUT or Matroska. - <screen>mplayer <replaceable>source_file.vob</replaceable> -aid 129 -dumpaudio -dumpfile <replaceable>sound.ac3</replaceable></screen> - will dump into the file <replaceable>sound.ac3</replaceable> the - audio track number 129 from the file - <replaceable>source_file.vob</replaceable> (NB: DVD VOB files - usually use a different audio numbering, - which means that the VOB audio track 129 is the 2nd audio track of the file). -</para> - -<para> - But sometimes you truly have no choice but to further compress the - sound so that more bits can be spent on the video. - Most people choose to compress audio with either MP3 or Vorbis audio - codecs. - While the latter is a very space-efficient codec, MP3 is better supported - by hardware players, although this trend is changing. -</para> - -<para> - Do <emphasis>not</emphasis> use <option>-nosound</option> when encoding - a file with audio, even if you will be encoding and muxing audio - separately later. - Though it may work in ideal cases, using <option>-nosound</option> is - likely to hide some problems in your encoding command line setting. - In other words, having a soundtrack during your encode assures you that, - provided you do not see messages such as - <quote>Too many audio packets in the buffer</quote>, you will be able - to get proper sync. -</para> - -<para> - You need to have <application>MEncoder</application> process the sound. - You can for example copy the orignal soundtrack during the encode with - <option>-oac copy</option> or convert it to a "light" 4 kHz mono WAV - PCM with <option>-oac pcm -channels 1 -srate 4000</option>. - Otherwise, in some cases, it will generate a video file that will not sync - with the audio. - Such cases are when the number of video frames in the source file does - not match up to the total length of audio frames or whenever there - are discontinuities/splices where there are missing or extra audio frames. - The correct way to handle this kind of problem is to insert silence or - cut audio at these points. - However <application>MPlayer</application> cannot do that, so if you - demux the AC3 audio and encode it with a separate app (or dump it to PCM with - <application>MPlayer</application>), the splices will be left incorrect - and the only way to correct them is to drop/dup video frames at the - splice. - As long as <application>MEncoder</application> sees the audio when it is - encoding the video, it can do this dropping/duping (which is usually OK - since it takes place at full black/scenechange), but if - <application>MEncoder</application> cannot see the audio, it will just - process all frames as-is and they will not fit the final audio stream when - you for example merge your audio and video track into a Matroska file. -</para> - -<para> - First of all, you will have to convert the DVD sound into a WAV file that the - audio codec can use as input. - For example: - <screen>mplayer <replaceable>source_file.vob</replaceable> -ao pcm:file=<replaceable>destination_sound.wav</replaceable> -vc dummy -aid 1 -vo null</screen> - will dump the second audio track from the file - <replaceable>source_file.vob</replaceable> into the file - <replaceable>destination_sound.wav</replaceable>. - You may want to normalize the sound before encoding, as DVD audio tracks - are commonly recorded at low volumes. - You can use the tool <application>normalize</application> for instance, - which is available in most distributions. - If you are using Windows, a tool such as <application>BeSweet</application> - can do the same job. - You will compress in either Vorbis or MP3. - For example: - <screen>oggenc -q1 <replaceable>destination_sound.wav</replaceable></screen> - will encode <replaceable>destination_sound.wav</replaceable> with - the encoding quality 1, which is roughly equivalent to 80Kb/s, and - is the minimum quality at which you should encode if you care about - quality. - Please note that <application>MEncoder</application> currently cannot - mux Vorbis audio tracks - into the output file because it only supports AVI and MPEG - containers as an output, each of which may lead to audio/video - playback synchronization problems with some players when the AVI file - contain VBR audio streams such as Vorbis. - Do not worry, this document will show you how you can do that with third - party programs. +Audio is a much simpler problem to solve: if you care about quality, just +leave it as is. +Even AC3 5.1 streams are at most 448Kbit/s, and they are worth every bit. +You might be tempted to transcode the audio to high quality Vorbis, but +just because you do not have an A/V receiver for AC3 pass-through today +does not mean you will not have one tomorrow. Future-proof your DVD rips by +preserving the AC3 stream. +You can keep the AC3 stream either by copying it directly into the video +stream <link linkend="menc-feat-mpeg4">during the encoding</link>. +You can also extract the AC3 stream in order to mux it into containers such +as NUT or Matroska. +<screen> +mplayer <replaceable>source_file.vob</replaceable> -aid 129 -dumpaudio -dumpfile <replaceable>sound.ac3</replaceable> +</screen> +will dump into the file <replaceable>sound.ac3</replaceable> the +audio track number 129 from the file +<replaceable>source_file.vob</replaceable> (NB: DVD VOB files +usually use a different audio numbering, +which means that the VOB audio track 129 is the 2nd audio track of the file). +</para> + +<para> +But sometimes you truly have no choice but to further compress the +sound so that more bits can be spent on the video. +Most people choose to compress audio with either MP3 or Vorbis audio codecs. +While the latter is a very space-efficient codec, MP3 is better supported +by hardware players, although this trend is changing. +</para> + +<para> +Do <emphasis>not</emphasis> use <option>-nosound</option> when encoding +a file with audio, even if you will be encoding and muxing audio +separately later. +Though it may work in ideal cases, using <option>-nosound</option> is +likely to hide some problems in your encoding command line setting. +In other words, having a soundtrack during your encode assures you that, +provided you do not see messages such as +<quote>Too many audio packets in the buffer</quote>, you will be able +to get proper sync. +</para> + +<para> +You need to have <application>MEncoder</application> process the sound. +You can for example copy the orignal soundtrack during the encode with +<option>-oac copy</option> or convert it to a "light" 4 kHz mono WAV +PCM with <option>-oac pcm -channels 1 -srate 4000</option>. +Otherwise, in some cases, it will generate a video file that will not sync +with the audio. +Such cases are when the number of video frames in the source file does +not match up to the total length of audio frames or whenever there +are discontinuities/splices where there are missing or extra audio frames. +The correct way to handle this kind of problem is to insert silence or +cut audio at these points. +However <application>MPlayer</application> cannot do that, so if you +demux the AC3 audio and encode it with a separate app (or dump it to PCM with +<application>MPlayer</application>), the splices will be left incorrect +and the only way to correct them is to drop/dup video frames at the +splice. +As long as <application>MEncoder</application> sees the audio when it is +encoding the video, it can do this dropping/duping (which is usually OK +since it takes place at full black/scenechange), but if +<application>MEncoder</application> cannot see the audio, it will just +process all frames as-is and they will not fit the final audio stream when +you for example merge your audio and video track into a Matroska file. +</para> + +<para> +First of all, you will have to convert the DVD sound into a WAV file that the +audio codec can use as input. +For example: +<screen> +mplayer <replaceable>source_file.vob</replaceable> -ao pcm:file=<replaceable>destination_sound.wav</replaceable> \ + -vc dummy -aid 1 -vo null +</screen> +will dump the second audio track from the file +<replaceable>source_file.vob</replaceable> into the file +<replaceable>destination_sound.wav</replaceable>. +You may want to normalize the sound before encoding, as DVD audio tracks +are commonly recorded at low volumes. +You can use the tool <application>normalize</application> for instance, +which is available in most distributions. +If you are using Windows, a tool such as <application>BeSweet</application> +can do the same job. +You will compress in either Vorbis or MP3. +For example: +<screen>oggenc -q1 <replaceable>destination_sound.wav</replaceable></screen> +will encode <replaceable>destination_sound.wav</replaceable> with +the encoding quality 1, which is roughly equivalent to 80Kb/s, and +is the minimum quality at which you should encode if you care about +quality. +Please note that <application>MEncoder</application> currently cannot +mux Vorbis audio tracks +into the output file because it only supports AVI and MPEG +containers as an output, each of which may lead to audio/video +playback synchronization problems with some players when the AVI file +contain VBR audio streams such as Vorbis. +Do not worry, this document will show you how you can do that with third +party programs. </para> - </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-muxing"> <title>Muxing</title> + <para> - Now that you have encoded your video, you will most likely want - to mux it with one or more audio tracks into a movie container, such - as AVI, MPEG, Matroska or NUT. - <application>MEncoder</application> is currently only able to natively output - audio and video into MPEG and AVI container formats. - for example: - <screen>mencoder -oac copy -ovc copy -o <replaceable>output_movie.avi</replaceable> -audiofile <replaceable>input_audio.mp2</replaceable> <replaceable>input_video.avi</replaceable></screen> - This would merge the video file <replaceable>input_video.avi</replaceable> - and the audio file <replaceable>input_audio.mp2</replaceable> - into the AVI file <replaceable>output_movie.avi</replaceable>. - This command works with MPEG-1 layer I, II and III (more commonly known - as MP3) audio, WAV and a few other audio formats too. -</para> - -<para> - <application>MEncoder</application> features experimental support for - <systemitem class="library">libavformat</systemitem>, which is a - library from the FFmpeg project that supports muxing and demuxing - a variety of containers. - For example: - <screen>mencoder -oac copy -ovc copy -o <replaceable>output_movie.asf</replaceable> -audiofile <replaceable>input_audio.mp2</replaceable> <replaceable>input_video.avi</replaceable> -of lavf -lavfopts format=asf</screen> - This will do the same thing as the previous example, except that - the output container will be ASF. - Please note that this support is highly experimental (but getting - better every day), and will only work if you compiled - <application>MPlayer</application> with the support for - <systemitem class="library">libavformat</systemitem> enabled (which - means that a pre-packaged binary version will not work in most cases). +Now that you have encoded your video, you will most likely want +to mux it with one or more audio tracks into a movie container, such +as AVI, MPEG, Matroska or NUT. +<application>MEncoder</application> is currently only able to natively output +audio and video into MPEG and AVI container formats. +for example: +<screen> +mencoder -oac copy -ovc copy -o <replaceable>output_movie.avi</replaceable> \ + -audiofile <replaceable>input_audio.mp2</replaceable> <replaceable>input_video.avi</replaceable> +</screen> +This would merge the video file <replaceable>input_video.avi</replaceable> +and the audio file <replaceable>input_audio.mp2</replaceable> +into the AVI file <replaceable>output_movie.avi</replaceable>. +This command works with MPEG-1 layer I, II and III (more commonly known +as MP3) audio, WAV and a few other audio formats too. +</para> + +<para> +<application>MEncoder</application> features experimental support for +<systemitem class="library">libavformat</systemitem>, which is a +library from the FFmpeg project that supports muxing and demuxing +a variety of containers. +For example: +<screen> +mencoder -oac copy -ovc copy -o <replaceable>output_movie.asf</replaceable> -audiofile <replaceable>input_audio.mp2</replaceable> \ + <replaceable>input_video.avi</replaceable> -of lavf -lavfopts format=asf +</screen> +This will do the same thing as the previous example, except that +the output container will be ASF. +Please note that this support is highly experimental (but getting +better every day), and will only work if you compiled +<application>MPlayer</application> with the support for +<systemitem class="library">libavformat</systemitem> enabled (which +means that a pre-packaged binary version will not work in most cases). </para> <sect3 id="menc-feat-dvd-mpeg4-muxing-filter-issues"> <title>Improving muxing and A/V sync reliability</title> + <para> - You may experience some serious A/V sync problems while trying to mux - your video and some audio tracks, where no matter how you adjust the - audio delay, you will never get proper sync. - That may happen when you use some video filters that will drop or - duplicate some frames, like the inverse telecine filters. - It is strongly encouraged to append the <option>harddup</option> video - filter at the end of the filter chain to avoid this kind of problem. +You may experience some serious A/V sync problems while trying to mux +your video and some audio tracks, where no matter how you adjust the +audio delay, you will never get proper sync. +That may happen when you use some video filters that will drop or +duplicate some frames, like the inverse telecine filters. +It is strongly encouraged to append the <option>harddup</option> video +filter at the end of the filter chain to avoid this kind of problem. </para> <para> - Without <option>harddup</option>, if <application>MEncoder</application> - wants to duplicate a frame, it relies on the muxer to put a mark on the - container so that the last frame will be displayed again to maintain - sync while writing no actual frame. - With <option>harddup</option>, <application>MEncoder</application> - will instead just push the last frame displayed again into the filter - chain. - This means that the encoder receives the <emphasis>exact</emphasis> - same frame twice, and compresses it. - This will result in a slightly bigger file, but will not cause problems - when demuxing or remuxing into other container formats. +Without <option>harddup</option>, if <application>MEncoder</application> +wants to duplicate a frame, it relies on the muxer to put a mark on the +container so that the last frame will be displayed again to maintain +sync while writing no actual frame. +With <option>harddup</option>, <application>MEncoder</application> +will instead just push the last frame displayed again into the filter +chain. +This means that the encoder receives the <emphasis>exact</emphasis> +same frame twice, and compresses it. +This will result in a slightly bigger file, but will not cause problems +when demuxing or remuxing into other container formats. </para> <para> - You may also have no choice but to use <option>harddup</option> with - container formats that are not too tightly linked with - <application>MEncoder</application> such as the ones supported through - <systemitem class="library">libavformat</systemitem>, which may not - support frame duplication at the container level. +You may also have no choice but to use <option>harddup</option> with +container formats that are not too tightly linked with +<application>MEncoder</application> such as the ones supported through +<systemitem class="library">libavformat</systemitem>, which may not +support frame duplication at the container level. </para> </sect3> <sect3 id="menc-feat-dvd-mpeg4-muxing-avi-limitations"> <title>Limitations of the AVI container</title> + <para> - Although it is the most widely-supported container format after MPEG-1, - AVI also has some major drawbacks. - Perhaps the most obvious is the overhead. - For each chunk of the AVI file, 24 bytes are wasted on headers and - index. - This translates into a little over 5 MB per hour, or 1-2.5% - overhead for a 700 MB movie. This may not seem like much, but it could - mean the difference between being able to use 700 kbit/sec video or - 714 kbit/sec, and every bit of quality counts. +Although it is the most widely-supported container format after MPEG-1, +AVI also has some major drawbacks. +Perhaps the most obvious is the overhead. +For each chunk of the AVI file, 24 bytes are wasted on headers and index. +This translates into a little over 5 MB per hour, or 1-2.5% +overhead for a 700 MB movie. This may not seem like much, but it could +mean the difference between being able to use 700 kbit/sec video or +714 kbit/sec, and every bit of quality counts. </para> <para> - In addition this gross inefficiency, AVI also has the following major - limitations: +In addition this gross inefficiency, AVI also has the following major +limitations: </para> <orderedlist> -<listitem> -<para> +<listitem><para> Only fixed-fps content can be stored. This is particularly limiting if the original material you want to encode is mixed content, for example a mix of NTSC video and film material. Actually there are hacks that can be used to store mixed-framerate content in AVI, but they increase the (already huge) overhead fivefold or more and so are not practical. -</para> -</listitem> -<listitem> -<para> +</para></listitem> +<listitem><para> Audio in AVI files must be either constant-bitrate (CBR) or constant-framesize (i.e. all frames decode to the same number of samples). @@ -1682,164 +1732,168 @@ Do not do this! Always use a file or CD/DVD/etc device as input. either of these requirements. Therefore, if you plan to store your movie in AVI, you will have to use a less efficient codec such as MP3 or AC3. -</para> -</listitem> +</para></listitem> </orderedlist> <para> - Having said all that, <application>MEncoder</application> does not - currently support variable-fps output or Vorbis encoding. - Therefore, you may not see these as limitations if - <application>MEncoder</application> is the - only tool you will be using to produce your encodes. - However, it is possible to use <application>MEncoder</application> - only for video encoding, and then use external tools to encode - audio and mux it into another container format. +Having said all that, <application>MEncoder</application> does not +currently support variable-fps output or Vorbis encoding. +Therefore, you may not see these as limitations if +<application>MEncoder</application> is the +only tool you will be using to produce your encodes. +However, it is possible to use <application>MEncoder</application> +only for video encoding, and then use external tools to encode +audio and mux it into another container format. </para> </sect3> + <sect3 id="menc-feat-dvd-mpeg4-muxing-matroska"> <title>Muxing into the Matroska container</title> + <para> - Matroska is a free, open standard container format, aiming - to offer a lot of advanced features, which older containers - like AVI cannot handle. - For example, Matroska supports variable bitrate audio content - (VBR), variable framerates (VFR), chapters, file attachments, - error detection code (EDC) and modern A/V Codecs like "Advanced Audio - Coding" (AAC), "Vorbis" or "MPEG-4 AVC" (H.264), next to nothing - handled by AVI. +Matroska is a free, open standard container format, aiming +to offer a lot of advanced features, which older containers +like AVI cannot handle. +For example, Matroska supports variable bitrate audio content +(VBR), variable framerates (VFR), chapters, file attachments, +error detection code (EDC) and modern A/V Codecs like "Advanced Audio +Coding" (AAC), "Vorbis" or "MPEG-4 AVC" (H.264), next to nothing +handled by AVI. </para> <para> - The tools required to create Matroska files are collectively called - <application>mkvtoolnix</application>, and are available for most - Unix platforms as well as <application>Windows</application>. - Because Matroska is an open standard you may find other - tools that suit you better, but since mkvtoolnix is the most - common, and is supported by the Matroska team itself, we will - only cover its usage. +The tools required to create Matroska files are collectively called +<application>mkvtoolnix</application>, and are available for most +Unix platforms as well as <application>Windows</application>. +Because Matroska is an open standard you may find other +tools that suit you better, but since mkvtoolnix is the most +common, and is supported by the Matroska team itself, we will +only cover its usage. </para> <para> - Probably the easiest way to get started with Matroska is to use - <application>MMG</application>, the graphical frontend shipped with - <application>mkvtoolnix</application>, and follow the - <ulink url="http://www.bunkus.org/videotools/mkvtoolnix/doc/mkvmerge-gui.html">guide to mkvmerge GUI (mmg)</ulink> +Probably the easiest way to get started with Matroska is to use +<application>MMG</application>, the graphical frontend shipped with +<application>mkvtoolnix</application>, and follow the +<ulink url="http://www.bunkus.org/videotools/mkvtoolnix/doc/mkvmerge-gui.html">guide to mkvmerge GUI (mmg)</ulink> </para> <para> - You may also mux audio and video files using the command line: - <screen>mkvmerge -o <replaceable>output.mkv</replaceable> <replaceable>input_video.avi</replaceable> <replaceable>input_audio1.mp3</replaceable> <replaceable>input_audio2.ac3</replaceable></screen> - This would merge the video file <replaceable>input_video.avi</replaceable> - and the two audio files <replaceable>input_audio1.mp3</replaceable> - and <replaceable>input_audio2.ac3</replaceable> into the Matroska - file <replaceable>output.mkv</replaceable>. - Matroska, as mentioned earlier, is able to do much more than that, like - multiple audio tracks (including fine-tuning of audio/video - synchronization), chapters, subtitles, splitting, etc... - Please refer to the documentation of those applications for - more details. +You may also mux audio and video files using the command line: +<screen> +mkvmerge -o <replaceable>output.mkv</replaceable> <replaceable>input_video.avi</replaceable> <replaceable>input_audio1.mp3</replaceable> <replaceable>input_audio2.ac3</replaceable> +</screen> +This would merge the video file <replaceable>input_video.avi</replaceable> +and the two audio files <replaceable>input_audio1.mp3</replaceable> +and <replaceable>input_audio2.ac3</replaceable> into the Matroska +file <replaceable>output.mkv</replaceable>. +Matroska, as mentioned earlier, is able to do much more than that, like +multiple audio tracks (including fine-tuning of audio/video +synchronization), chapters, subtitles, splitting, etc... +Please refer to the documentation of those applications for +more details. </para> - </sect3> - </sect2> - </sect1> + +<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --> + + <sect1 id="menc-feat-telecine"> <title>How to deal with telecine and interlacing within NTSC DVDs</title> <sect2 id="menc-feat-telecine-intro"> <title>Introduction</title> + <formalpara> <title>What is telecine?</title> <para> - If you do not understand much of what is written in this document, - read the - <ulink url="http://en.wikipedia.org/wiki/Telecine">Wikipedia entry on telecine</ulink>. - It is an understandable and reasonably comprehensive - description of what telecine is. +If you do not understand much of what is written in this document, read the +<ulink url="http://en.wikipedia.org/wiki/Telecine">Wikipedia entry on telecine</ulink>. +It is an understandable and reasonably comprehensive +description of what telecine is. </para></formalpara> <formalpara> <title>A note about the numbers.</title> <para> - Many documents, including the guide linked above, refer to the fields - per second value of NTSC video as 59.94 and the corresponding frames - per second values as 29.97 (for telecined and interlaced) and 23.976 - (for progressive). For simplicity, some documents even round these - numbers to 60, 30, and 24. +Many documents, including the guide linked above, refer to the fields +per second value of NTSC video as 59.94 and the corresponding frames +per second values as 29.97 (for telecined and interlaced) and 23.976 +(for progressive). For simplicity, some documents even round these +numbers to 60, 30, and 24. </para></formalpara> <para> - Strictly speaking, all those numbers are approximations. Black and - white NTSC video was exactly 60 fields per second, but 60000/1001 - was later chosen to accomodate color data while remaining compatible - with contemporary black and white televisions. Digital NTSC video - (such as on a DVD) is also 60000/1001 fields per second. From this, - interlaced and telecined video are derived to be 30000/1001 frames - per second; progressive video is 24000/1001 frames per second. +Strictly speaking, all those numbers are approximations. Black and +white NTSC video was exactly 60 fields per second, but 60000/1001 +was later chosen to accomodate color data while remaining compatible +with contemporary black and white televisions. Digital NTSC video +(such as on a DVD) is also 60000/1001 fields per second. From this, +interlaced and telecined video are derived to be 30000/1001 frames +per second; progressive video is 24000/1001 frames per second. </para> <para> - Older versions of the <application>MEncoder</application> documentation - and many archived mailing list posts refer to 59.94, 29.97, and 23.976. - All <application>MEncoder</application> documentation has been updated - to use the fractional values, and you should use them too. +Older versions of the <application>MEncoder</application> documentation +and many archived mailing list posts refer to 59.94, 29.97, and 23.976. +All <application>MEncoder</application> documentation has been updated +to use the fractional values, and you should use them too. </para> <para> - <option>-ofps 23.976</option> is incorrect. - <option>-ofps 24000/1001</option> should be used instead. +<option>-ofps 23.976</option> is incorrect. +<option>-ofps 24000/1001</option> should be used instead. </para> <formalpara> <title>How telecine is used.</title> <para> - All video intended to be displayed on an NTSC - television set must be 60000/1001 fields per second. Made-for-TV movies -4 and shows are often filmed directly at 60000/1001 fields per second, but - the majority of cinema is filmed at 24 or 24000/1001 frames per - second. When cinematic movie DVDs are mastered, the video is then - converted for television using a process called telecine. +All video intended to be displayed on an NTSC +television set must be 60000/1001 fields per second. Made-for-TV movies +and shows are often filmed directly at 60000/1001 fields per second, but +the majority of cinema is filmed at 24 or 24000/1001 frames per +second. When cinematic movie DVDs are mastered, the video is then +converted for television using a process called telecine. </para></formalpara> <para> - On a DVD, the video is never actually stored as 60000/1001 fields per - second. For video that was originally 60000/1001, each pair of fields is - combined to form a frame, resulting in 30000/1001 frames per - second. Hardware DVD players then read a flag embedded in the video - stream to determine whether the odd- or even-numbered lines should - form the first field. +On a DVD, the video is never actually stored as 60000/1001 fields per +second. For video that was originally 60000/1001, each pair of fields is +combined to form a frame, resulting in 30000/1001 frames per +second. Hardware DVD players then read a flag embedded in the video +stream to determine whether the odd- or even-numbered lines should +form the first field. </para> <para> - Usually, 24000/1001 frames per second content stays as it is when - encoded for a DVD, and the DVD player must perform telecining - on-the-fly. Sometimes, however, the video is telecined - <emphasis>before</emphasis> being stored on the DVD; even though it - was originally 24000/1001 frames per second, it becomes 60000/1001 fields per - second. When it is stored on the DVD, pairs of fields are combined to form - 30000/1001 frames per second. +Usually, 24000/1001 frames per second content stays as it is when +encoded for a DVD, and the DVD player must perform telecining +on-the-fly. Sometimes, however, the video is telecined +<emphasis>before</emphasis> being stored on the DVD; even though it +was originally 24000/1001 frames per second, it becomes 60000/1001 fields per +second. When it is stored on the DVD, pairs of fields are combined to form +30000/1001 frames per second. </para> <para> - When looking at individual frames formed from 60000/1001 fields per - second video, telecined or otherwise, interlacing is clearly visible - wherever there is any motion, because one field (say, the - even-numbered lines) represents a moment in time 1/(60000/1001) - seconds later than the other. Playing interlaced video on a computer - looks ugly both because the monitor is higher resolution and because - the video is shown frame-after-frame instead of field-after-field. +When looking at individual frames formed from 60000/1001 fields per +second video, telecined or otherwise, interlacing is clearly visible +wherever there is any motion, because one field (say, the +even-numbered lines) represents a moment in time 1/(60000/1001) +seconds later than the other. Playing interlaced video on a computer +looks ugly both because the monitor is higher resolution and because +the video is shown frame-after-frame instead of field-after-field. </para> <itemizedlist> <title>Notes:</title> <listitem><para> This section only applies to NTSC DVDs, and not PAL. - </para></listitem> +</para></listitem> <listitem><para> The example <application>MEncoder</application> lines throughout the document are <emphasis role="bold">not</emphasis> intended for @@ -1847,235 +1901,245 @@ Do not do this! Always use a file or CD/DVD/etc device as input. pertaining video category. How to make good DVD rips or fine-tune <systemitem class="library">libavcodec</systemitem> for maximal quality is not within the scope of this document. - </para></listitem> +</para></listitem> <listitem><para> There are a couple footnotes specific to this guide, linked like this: <link linkend="menc-feat-telecine-footnotes">[1]</link> - </para></listitem> +</para></listitem> </itemizedlist> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-telecine-ident"> <title>How to tell what type of video you have</title> <sect3 id="menc-feat-telecine-ident-progressive"> <title>Progressive</title> + <para> - Progressive video was originally filmed at 24000/1001 fps, and stored - on the DVD without alteration. +Progressive video was originally filmed at 24000/1001 fps, and stored +on the DVD without alteration. </para> <para> - When you play a progressive DVD in <application>MPlayer</application>, - <application>MPlayer</application> will print the following line as - soon as the movie begins to play: - - <screen> demux_mpg: 24000/1001 fps progressive NTSC content detected, switching framerate.</screen> - - From this point forward, demux_mpg should never say it finds - "30000/1001 fps NTSC content." +When you play a progressive DVD in <application>MPlayer</application>, +<application>MPlayer</application> will print the following line as +soon as the movie begins to play: +<screen> +demux_mpg: 24000/1001 fps progressive NTSC content detected, switching framerate. +</screen> +From this point forward, demux_mpg should never say it finds +"30000/1001 fps NTSC content." </para> <para> - When you watch progressive video, you should never see any - interlacing. Beware, however, because sometimes there is a tiny bit - of telecine mixed in where you would not expect. I have encountered TV - show DVDs that have one second of telecine at every scene change, or - at seemingly random places. I once watched a DVD that had a - progressive first half, and the second half was telecined. If you - want to be <emphasis>really</emphasis> thorough, you can scan the - entire movie: - - <screen>mplayer dvd://1 -nosound -vo null -benchmark</screen> - - Using <option>-benchmark</option> makes - <application>MPlayer</application> play the movie as quickly as it - possibly can; still, depending on your hardware, it can take a - while. Every time demux_mpg reports a framerate change, the line - immediately above will show you the time at which the change - occurred. +When you watch progressive video, you should never see any +interlacing. Beware, however, because sometimes there is a tiny bit +of telecine mixed in where you would not expect. I have encountered TV +show DVDs that have one second of telecine at every scene change, or +at seemingly random places. I once watched a DVD that had a +progressive first half, and the second half was telecined. If you +want to be <emphasis>really</emphasis> thorough, you can scan the +entire movie: +<screen>mplayer dvd://1 -nosound -vo null -benchmark</screen> +Using <option>-benchmark</option> makes +<application>MPlayer</application> play the movie as quickly as it +possibly can; still, depending on your hardware, it can take a +while. Every time demux_mpg reports a framerate change, the line +immediately above will show you the time at which the change +occurred. </para> <para> - Sometimes progressive video on DVDs is referred to as - "soft-telecine" because it is intended to - be telecined by the DVD player. +Sometimes progressive video on DVDs is referred to as +"soft-telecine" because it is intended to +be telecined by the DVD player. </para> </sect3> + <sect3 id="menc-feat-telecine-ident-telecined"> <title>Telecined</title> + <para> - Telecined video was originally filmed at 24000/1001, but was telecined - <emphasis>before</emphasis> it was written to the DVD. +Telecined video was originally filmed at 24000/1001, but was telecined +<emphasis>before</emphasis> it was written to the DVD. </para> <para> - <application>MPlayer</application> does not (ever) report any - framerate changes when it plays telecined video. +<application>MPlayer</application> does not (ever) report any +framerate changes when it plays telecined video. </para> <para> - Watching a telecined video, you will see interlacing artifacts that - seem to "blink": they repeatedly appear and disappear. - You can look closely at this by - <orderedlist> - <listitem> - <screen>mplayer dvd://1</screen> - </listitem> - <listitem><para> - Seek to a part with motion. - </para></listitem> - <listitem><para> - Use the <keycap>.</keycap> key to step forward one frame at a time. - </para></listitem> - <listitem><para> - Look at the pattern of interlaced-looking and progressive-looking - frames. If the pattern you see is PPPII,PPPII,PPPII,... then the - video is telecined. If you see some other pattern, then the video - may have been telecined using some non-standard method; - <application>MEncoder</application> cannot losslessly convert - non-standard telecine to progressive. If you do not see any - pattern at all, then it is most likely interlaced. - </para></listitem> - </orderedlist> +Watching a telecined video, you will see interlacing artifacts that +seem to "blink": they repeatedly appear and disappear. +You can look closely at this by +<orderedlist> +<listitem><screen>mplayer dvd://1</screen></listitem> +<listitem><para> + Seek to a part with motion. +</para></listitem> +<listitem><para> + Use the <keycap>.</keycap> key to step forward one frame at a time. +</para></listitem> +<listitem><para> + Look at the pattern of interlaced-looking and progressive-looking + frames. If the pattern you see is PPPII,PPPII,PPPII,... then the + video is telecined. If you see some other pattern, then the video + may have been telecined using some non-standard method; + <application>MEncoder</application> cannot losslessly convert + non-standard telecine to progressive. If you do not see any + pattern at all, then it is most likely interlaced. +</para></listitem> +</orderedlist> </para> <para> - Sometimes telecined video on DVDs is referred to as - "hard-telecine". Since hard-telecine is already 60000/1001 fields - per second, the DVD player plays the video without any manipulation. +Sometimes telecined video on DVDs is referred to as +"hard-telecine". Since hard-telecine is already 60000/1001 fields +per second, the DVD player plays the video without any manipulation. </para> <para> - Another way to tell if your source is telecined or not is to play - the source with the <option>-vf pullup</option> and <option>-v</option> - command line options to see how <option>pullup</option> matches frames. - If the source is telecined, you should see on the console a 3:2 pattern - with <systemitem>0+.1.+2</systemitem> and <systemitem>0++1</systemitem> - alternating. - This technique has the advantage that you do not need to watch the - source to identify it, which could be useful if you wish to automate - the encoding procedure, or to carry out said procedure remotely via - a slow connection. +Another way to tell if your source is telecined or not is to play +the source with the <option>-vf pullup</option> and <option>-v</option> +command line options to see how <option>pullup</option> matches frames. +If the source is telecined, you should see on the console a 3:2 pattern +with <systemitem>0+.1.+2</systemitem> and <systemitem>0++1</systemitem> +alternating. +This technique has the advantage that you do not need to watch the +source to identify it, which could be useful if you wish to automate +the encoding procedure, or to carry out said procedure remotely via +a slow connection. </para> - </sect3> + <sect3 id="menc-feat-telecine-ident-interlaced"> <title>Interlaced</title> + <para> - Interlaced video was originally filmed at 60000/1001 fields per second, - and stored on the DVD as 30000/1001 frames per second. The interlacing effect - (often called "combing") is a result of combining pairs of - fields into frames. Each field is supposed to be 1/(60000/1001) seconds apart, - and when they are displayed simultaneously the difference is apparent. +Interlaced video was originally filmed at 60000/1001 fields per second, +and stored on the DVD as 30000/1001 frames per second. The interlacing effect +(often called "combing") is a result of combining pairs of +fields into frames. Each field is supposed to be 1/(60000/1001) seconds apart, +and when they are displayed simultaneously the difference is apparent. </para> <para> - As with telecined video, <application>MPlayer</application> should - not ever report any framerate changes when playing interlaced content. +As with telecined video, <application>MPlayer</application> should +not ever report any framerate changes when playing interlaced content. </para> <para> - When you view an interlaced video closely by frame-stepping with the - <keycap>.</keycap> key, you will see that every single frame is interlaced. +When you view an interlaced video closely by frame-stepping with the +<keycap>.</keycap> key, you will see that every single frame is interlaced. </para> </sect3> + <sect3 id="menc-feat-telecine-ident-mixedpt"> <title>Mixed progressive and telecine</title> + <para> - All of a "mixed progressive and telecine" video was originally - 24000/1001 frames per second, but some parts of it ended up being telecined. +All of a "mixed progressive and telecine" video was originally +24000/1001 frames per second, but some parts of it ended up being telecined. </para> <para> - When <application>MPlayer</application> plays this category, it will - (often repeatedly) switch back and forth between "30000/1001 fps NTSC" - and "24000/1001 fps progressive NTSC". Watch the bottom of - <application>MPlayer</application>'s output to see these messages. +When <application>MPlayer</application> plays this category, it will +(often repeatedly) switch back and forth between "30000/1001 fps NTSC" +and "24000/1001 fps progressive NTSC". Watch the bottom of +<application>MPlayer</application>'s output to see these messages. </para> <para> - You should check the "30000/1001 fps NTSC" sections to make sure - they are actually telecine, and not just interlaced. +You should check the "30000/1001 fps NTSC" sections to make sure +they are actually telecine, and not just interlaced. </para> </sect3> + <sect3 id="menc-feat-telecine-ident-mixedpi"> <title>Mixed progressive and interlaced</title> + <para> - In "mixed progressive and interlaced" content, progressive - and interlaced video have been spliced together. +In "mixed progressive and interlaced" content, progressive +and interlaced video have been spliced together. </para> <para> - This category looks just like "mixed progressive and telecine", - until you examine the 30000/1001 fps sections and see that they do not have the - telecine pattern. +This category looks just like "mixed progressive and telecine", +until you examine the 30000/1001 fps sections and see that they do not have the +telecine pattern. </para> </sect3> - </sect2> +<!-- ********** --> + <sect2 id="menc-feat-telecine-encode"> <title>How to encode each category</title> <para> - As I mentioned in the beginning, example <application>MEncoder</application> - lines below are <emphasis role="bold">not</emphasis> meant to actually be used; - they only demonstrate the minimum parameters to properly encode each category. +As I mentioned in the beginning, example <application>MEncoder</application> +lines below are <emphasis role="bold">not</emphasis> meant to actually be used; +they only demonstrate the minimum parameters to properly encode each category. </para> + <sect3 id="menc-feat-telecine-encode-progressive"> <title>Progressive</title> <para> - Progressive video requires no special filtering to encode. The only - parameter you need to be sure to use is - <option>-ofps 24000/1001</option>. Otherwise, <application>MEncoder</application> - will try to encode at 30000/1001 fps and will duplicate frames. +Progressive video requires no special filtering to encode. The only +parameter you need to be sure to use is <option>-ofps 24000/1001</option>. +Otherwise, <application>MEncoder</application> +will try to encode at 30000/1001 fps and will duplicate frames. </para> <para> - <screen>mencoder dvd://1 -oac copy -ovc lavc -ofps 24000/1001</screen> +<screen>mencoder dvd://1 -oac copy -ovc lavc -ofps 24000/1001</screen> </para> <para> - It is often the case, however, that a video that looks progressive - actually has very short parts of telecine mixed in. Unless you are - sure, it is safest to treat the video as - <link linkend="menc-feat-telecine-encode-mixedpt">mixed progressive and telecine</link>. - The performance loss is small - <link linkend="menc-feat-telecine-footnotes">[3]</link>. +It is often the case, however, that a video that looks progressive +actually has very short parts of telecine mixed in. Unless you are +sure, it is safest to treat the video as +<link linkend="menc-feat-telecine-encode-mixedpt">mixed progressive and telecine</link>. +The performance loss is small +<link linkend="menc-feat-telecine-footnotes">[3]</link>. </para> </sect3> + <sect3 id="menc-feat-telecine-encode-telecined"> <title>Telecined</title> + <para> - Telecine can be reversed to retrieve the original 24000/1001 content, - using a process called inverse-telecine. - <application>MPlayer</application> contains several filters to - accomplish this; the best filter, <option>pullup</option>, is described - in the <link linkend="menc-feat-telecine-encode-mixedpt">mixed - progressive and telecine</link> section. +Telecine can be reversed to retrieve the original 24000/1001 content, +using a process called inverse-telecine. +<application>MPlayer</application> contains several filters to +accomplish this; the best filter, <option>pullup</option>, is described +in the <link linkend="menc-feat-telecine-encode-mixedpt">mixed +progressive and telecine</link> section. </para> </sect3> + <sect3 id="menc-feat-telecine-encode-interlaced"> <title>Interlaced</title> + <para> - For most practical cases it is not possible to retrieve a complete - progressive video from interlaced content. The only way to do so - without losing half of the vertical resolution is to double the - framerate and try to "guess" what ought to make up the - corresponding lines for each field (this has drawbacks - see method - 3). +For most practical cases it is not possible to retrieve a complete +progressive video from interlaced content. The only way to do so +without losing half of the vertical resolution is to double the +framerate and try to "guess" what ought to make up the +corresponding lines for each field (this has drawbacks - see method 3). </para> <orderedlist> <listitem><para> - Encode the video in interlaced form. Normally, interlacing wreaks havoc with the encoder's ability to compress well, but <systemitem class="library">libavcodec</systemitem> has two @@ -2085,9 +2149,8 @@ Do not do this! Always use a file or CD/DVD/etc device as input. <link linkend="menc-feat-telecine-footnotes">[2] </link> because it will encode macroblocks as non-interlaced in places where there is no motion. Note that <option>-ofps</option> is NOT needed here. - <screen>mencoder dvd://1 -oac copy -ovc lavc -lavcopts ildct:ilme:mbd=2</screen> - </para></listitem> +</para></listitem> <listitem><para> Use a deinterlacing filter before encoding. There are several of these filters available to choose from, each with its own advantages @@ -2103,9 +2166,8 @@ Do not do this! Always use a file or CD/DVD/etc device as input. <option>-ofps</option>. Also, deinterlacing should be done after cropping <link linkend="menc-feat-telecine-footnotes">[1]</link> and before scaling. - <screen>mencoder dvd://1 -oac copy -vf yadif -ovc lavc</screen> - </para></listitem> +</para></listitem> <listitem><para> Unfortunately, this option is buggy with <application>MEncoder</application>; it ought to work well with @@ -2128,9 +2190,11 @@ Do not do this! Always use a file or CD/DVD/etc device as input. <emphasis role="bold">have to</emphasis> specify both <option>-fps</option> and <option>-ofps</option> to be twice the framerate of your original source. - - <screen>mencoder dvd://1 -oac copy -vf tfields=2 -ovc lavc -fps 60000/1001 -ofps 60000/1001</screen> - </para></listitem> + <screen> +mencoder dvd://1 -oac copy -vf tfields=2 -ovc lavc \ + -fps 60000/1001 -ofps 60000/1001<!-- + --></screen> +</para></listitem> <listitem><para> If you plan on downscaling dramatically, you can extract and encode only one of the two fields. Of course, you will lose half the vertical @@ -2142,23 +2206,25 @@ Do not do this! Always use a file or CD/DVD/etc device as input. appropriately. Remember that you will have to adjust the scale to compensate for the vertical resolution being halved. <screen>mencoder dvd://1 -oac copy -vf field=0 -ovc lavc</screen> - </para></listitem> +</para></listitem> </orderedlist> </sect3> + <sect3 id="menc-feat-telecine-encode-mixedpt"> <title>Mixed progressive and telecine</title> + <para> - In order to turn mixed progressive and telecine video into entirely - progressive video, the telecined parts have to be - inverse-telecined. There are three ways to accomplish this, - described below. Note that you should - <emphasis role="bold">always</emphasis> inverse-telecine before any - rescaling; unless you really know what you are doing, - inverse-telecine before cropping, too - <link linkend="menc-feat-telecine-footnotes">[1]</link>. - <option>-ofps 24000/1001</option> is needed here because the output video - will be 24000/1001 frames per second. +In order to turn mixed progressive and telecine video into entirely +progressive video, the telecined parts have to be +inverse-telecined. There are three ways to accomplish this, +described below. Note that you should +<emphasis role="bold">always</emphasis> inverse-telecine before any +rescaling; unless you really know what you are doing, +inverse-telecine before cropping, too +<link linkend="menc-feat-telecine-footnotes">[1]</link>. +<option>-ofps 24000/1001</option> is needed here because the output video +will be 24000/1001 frames per second. </para> <itemizedlist> @@ -2171,13 +2237,12 @@ Do not do this! Always use a file or CD/DVD/etc device as input. <option>pullup</option> is, however, the cleanest and most accurate method available for encoding both telecine and "mixed progressive and telecine". - - <screen>mencoder dvd://1 -oac copy -vf pullup,softskip -ovc lavc -ofps 24000/1001</screen> - </para> - - - </listitem> - <listitem><para> + <screen> +mencoder dvd://1 -oac copy -vf pullup,softskip + -ovc lavc -ofps 24000/1001<!-- + --></screen> +</para></listitem> +<listitem><para> An older method is to, rather than inverse-telecine the telecined parts, telecine the non-telecined parts and then inverse-telecine the whole @@ -2186,35 +2251,39 @@ Do not do this! Always use a file or CD/DVD/etc device as input. softpulldown with either <option>detc</option> or <option>ivtc</option>, the final result will be entirely progressive. <option>-ofps 24000/1001</option> is needed. - - <screen>mencoder dvd://1 -oac copy -vf softpulldown,ivtc=1 -ovc lavc -ofps 24000/1001</screen> - </para> - </listitem> + <screen> +mencoder dvd://1 -oac copy -vf softpulldown,ivtc=1 -ovc lavc -ofps 24000/1001 + </screen> +</para></listitem> <listitem><para> I have not used <option>-vf filmdint</option> myself, but here is what D Richard Felker III has to say: <blockquote><para>It is OK, but IMO it tries to deinterlace rather - than doing inverse telecine too often (much like settop DVD - players & progressive TVs) which gives ugly flickering and - other artifacts. If you are going to use it, you at least need to - spend some time tuning the options and watching the output first - to make sure it is not messing up.</para></blockquote> - </para></listitem> + than doing inverse telecine too often (much like settop DVD + players & progressive TVs) which gives ugly flickering and + other artifacts. If you are going to use it, you at least need to + spend some time tuning the options and watching the output first + to make sure it is not messing up. + </para></blockquote> +</para></listitem> </itemizedlist> </sect3> + <sect3 id="menc-feat-telecine-encode-mixedpi"> <title>Mixed progressive and interlaced</title> + <para> - There are two options for dealing with this category, each of - which is a compromise. You should decide based on the - duration/location of each type. +There are two options for dealing with this category, each of +which is a compromise. You should decide based on the +duration/location of each type. </para> <itemizedlist> -<listitem><para> +<listitem> + <para> Treat it as progressive. The interlaced parts will look interlaced, and some of the interlaced fields will have to be dropped, resulting in a bit of uneven jumpiness. You can use a postprocessing filter if @@ -2251,23 +2320,25 @@ Do not do this! Always use a file or CD/DVD/etc device as input. only half progressive, you probably want to encode it as if it is all interlaced. </para> - </listitem> +</listitem> <listitem><para> Treat it as interlaced. Some frames of the progressive parts will need to be duplicated, resulting in uneven jumpiness. Again, deinterlacing filters may slightly degrade the progressive parts. - </para></listitem> - +</para></listitem> </itemizedlist> </sect3> - </sect2> +<!-- ********** --> + <sect2 id="menc-feat-telecine-footnotes"> <title>Footnotes</title> + <orderedlist> -<listitem><formalpara> +<listitem> + <formalpara> <title>About cropping:</title> <para> Video data on DVDs are stored in a format called YUV 4:2:0. In YUV @@ -2311,7 +2382,7 @@ Do not do this! Always use a file or CD/DVD/etc device as input. vertically by multiples of four unless you use <option>-vf field</option> before cropping. </para> - </listitem> +</listitem> <listitem><formalpara> <title>About encoding parameters and quality:</title> @@ -2327,8 +2398,7 @@ Do not do this! Always use a file or CD/DVD/etc device as input. encoding quality (and decrease encoding speed) but that is beyond the scope of this document. </para> - </formalpara> - </listitem> +</formalpara></listitem> <listitem><formalpara> <title>About the performance of pullup:</title> @@ -2342,16 +2412,15 @@ Do not do this! Always use a file or CD/DVD/etc device as input. </option> overshadows that difference, bringing the performance decrease of using <option>pullup</option> down to 2%. </para> - </formalpara> - </listitem> - +</formalpara></listitem> </orderedlist> - </sect2> - </sect1> +<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --> + + <sect1 id="menc-feat-enc-libavcodec"> <title>Encoding with the <systemitem class="library">libavcodec</systemitem> codec family</title> @@ -2362,99 +2431,130 @@ provides simple encoding to a lot of interesting video and audio formats. You can encode to the following codecs (more or less up to date): </para> +<!-- ********** --> + <sect2 id="menc-feat-enc-libavcodec-video-codecs"> -<title><systemitem class="library">libavcodec</systemitem>'s video codecs</title> +<title><systemitem class="library">libavcodec</systemitem>'s + video codecs</title> <para> <informaltable frame="all"> <tgroup cols="2"> <thead> -<row><entry>Video codec name</entry><entry>Description</entry></row> + <row><entry>Video codec name</entry><entry>Description</entry></row> </thead> <tbody> -<row><entry>mjpeg</entry><entry> - Motion JPEG - </entry></row> -<row><entry>ljpeg</entry><entry> - lossless JPEG - </entry></row> -<row><entry>h261</entry><entry> - H.261 - </entry></row> -<row><entry>h263</entry><entry> - H.263 - </entry></row> -<row><entry>h263p</entry><entry> - H.263+ - </entry></row> -<row><entry>mpeg4</entry><entry> - ISO standard MPEG-4 (DivX, Xvid compatible) - </entry></row> -<row><entry>msmpeg4</entry><entry> - pre-standard MPEG-4 variant by MS, v3 (AKA DivX3) - </entry></row> -<row><entry>msmpeg4v2</entry><entry> - pre-standard MPEG-4 by MS, v2 (used in old ASF files) - </entry></row> -<row><entry>wmv1</entry><entry> - Windows Media Video, version 1 (AKA WMV7) - </entry></row> -<row><entry>wmv2</entry><entry> - Windows Media Video, version 2 (AKA WMV8) - </entry></row> -<row><entry>rv10</entry><entry> - RealVideo 1.0 - </entry></row> -<row><entry>rv20</entry><entry> - RealVideo 2.0 - </entry></row> -<row><entry>mpeg1video</entry><entry> - MPEG-1 video - </entry></row> -<row><entry>mpeg2video</entry><entry> - MPEG-2 video - </entry></row> -<row><entry>huffyuv</entry><entry> - lossless compression - </entry></row> -<row><entry>asv1</entry><entry> - ASUS Video v1 - </entry></row> -<row><entry>asv2</entry><entry> - ASUS Video v2 - </entry></row> -<row><entry>ffv1</entry><entry> - FFmpeg's lossless video codec - </entry></row> -<row><entry>svq1</entry><entry> - Sorenson video 1 - </entry></row> -<row><entry>flv</entry><entry> - Sorenson H.263 used in Flash Video - </entry></row> -<row><entry>dvvideo</entry><entry> - Sony Digital Video - </entry></row> -<row><entry>snow</entry><entry> - FFmpeg's experimental wavelet-based codec - </entry></row> +<row> + <entry>mjpeg</entry> + <entry>Motion JPEG</entry> +</row> +<row> + <entry>ljpeg</entry> + <entry>lossless JPEG</entry> +</row> +<row> + <entry>h261</entry> + <entry>H.261</entry> +</row> +<row> + <entry>h263</entry> + <entry>H.263 </entry> +</row> +<row> + <entry>h263p</entry> + <entry>H.263+</entry> +</row> +<row> + <entry>mpeg4</entry> + <entry>ISO standard MPEG-4 (DivX, Xvid compatible)</entry> +</row> +<row> + <entry>msmpeg4</entry> + <entry>pre-standard MPEG-4 variant by MS, v3 (AKA DivX3)</entry> +</row> +<row> + <entry>msmpeg4v2</entry> + <entry>pre-standard MPEG-4 by MS, v2 (used in old ASF files)</entry> +</row> +<row> + <entry>wmv1</entry> + <entry>Windows Media Video, version 1 (AKA WMV7)</entry> +</row> +<row> + <entry>wmv2</entry> + <entry>Windows Media Video, version 2 (AKA WMV8)</entry> +</row> +<row> + <entry>rv10</entry> + <entry>RealVideo 1.0</entry> +</row> +<row> + <entry>rv20</entry> + <entry>RealVideo 2.0</entry> +</row> +<row> + <entry>mpeg1video</entry> + <entry>MPEG-1 video</entry> +</row> +<row> + <entry>mpeg2video</entry> + <entry>MPEG-2 video</entry> +</row> +<row> + <entry>huffyuv</entry> + <entry>lossless compression</entry> +</row> +<row> + <entry>asv1</entry> + <entry>ASUS Video v1</entry> +</row> +<row> + <entry>asv2</entry> + <entry>ASUS Video v2</entry> +</row> +<row> + <entry>ffv1</entry> + <entry>FFmpeg's lossless video codec</entry> +</row> +<row> + <entry>svq1</entry> + <entry>Sorenson video 1</entry> +</row> +<row> + <entry>flv</entry> + <entry>Sorenson H.263 used in Flash Video</entry> +</row> +<row> + <entry>dvvideo</entry> + <entry>Sony Digital Video</entry> +</row> +<row> + <entry>snow</entry> + <entry>FFmpeg's experimental wavelet-based codec</entry> +</row> </tbody> </tgroup> </informaltable> The first column contains the codec names that should be passed after the -<literal>vcodec</literal> config, like: <option>-lavcopts vcodec=msmpeg4</option> +<literal>vcodec</literal> config, +like: <option>-lavcopts vcodec=msmpeg4</option> </para> -<informalexample> -<para> + +<informalexample><para> An example with MJPEG compression: -<screen>mencoder dvd://2 -o title2.avi -ovc lavc -lavcopts vcodec=mjpeg -oac copy</screen> -</para> -</informalexample> +<screen> +mencoder dvd://2 -o <replaceable>title2.avi</replaceable> -ovc lavc -lavcopts vcodec=mjpeg -oac copy +</screen> +</para></informalexample> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-enc-libavcodec-audio-codecs"> -<title><systemitem class="library">libavcodec</systemitem>'s audio codecs</title> +<title><systemitem class="library">libavcodec</systemitem>'s + audio codecs</title> + <para> <informaltable frame="all"> <tgroup cols="2"> @@ -2462,22 +2562,22 @@ An example with MJPEG compression: <row><entry>Audio codec name</entry><entry>Description</entry></row> </thead> <tbody> - <row> - <entry>mp2</entry> - <entry>MPEG Layer 2</entry> - </row> - <row> - <entry>ac3</entry> - <entry>AC3, AKA Dolby Digital</entry> - </row> - <row> - <entry>adpcm_ima_wav</entry> - <entry>IMA adaptive PCM (4 bits per sample, 4:1 compression)</entry> - </row> - <row> - <entry>sonic</entry> - <entry>experimental lossy/lossless codec</entry> - </row> +<row> + <entry>mp2</entry> + <entry>MPEG Layer 2</entry> +</row> +<row> + <entry>ac3</entry> + <entry>AC3, AKA Dolby Digital</entry> +</row> +<row> + <entry>adpcm_ima_wav</entry> + <entry>IMA adaptive PCM (4 bits per sample, 4:1 compression)</entry> +</row> +<row> + <entry>sonic</entry> + <entry>experimental lossy/lossless codec</entry> +</row> </tbody> </tgroup> </informaltable> @@ -2486,44 +2586,44 @@ The first column contains the codec names that should be passed after the <literal>acodec</literal> option, like: <option>-lavcopts acodec=ac3</option> </para> -<informalexample> -<para> +<informalexample><para> An example with AC3 compression: -<screen>mencoder dvd://2 -o title2.avi -oac lavc -lavcopts acodec=ac3 -ovc copy</screen> -</para> -</informalexample> +<screen> +mencoder dvd://2 -o <replaceable>title2.avi</replaceable> -oac lavc -lavcopts acodec=ac3 -ovc copy +</screen> +</para></informalexample> <para> - Contrary to <systemitem class="library">libavcodec</systemitem>'s video - codecs, its audio codecs do not make a wise usage of the bits they are - given as they lack some minimal psychoacoustic model (if at all) - which most other codec implementations feature. - However, note that all these audio codecs are very fast and work - out-of-the-box everywhere <application>MEncoder</application> has been - compiled with <systemitem class="library">libavcodec</systemitem> (which - is the case most of time), and do not depend on external libraries. +Contrary to <systemitem class="library">libavcodec</systemitem>'s video +codecs, its audio codecs do not make a wise usage of the bits they are +given as they lack some minimal psychoacoustic model (if at all) +which most other codec implementations feature. +However, note that all these audio codecs are very fast and work +out-of-the-box everywhere <application>MEncoder</application> has been +compiled with <systemitem class="library">libavcodec</systemitem> (which +is the case most of time), and do not depend on external libraries. </para> </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-lavc-encoding-options"> <title>Encoding options of libavcodec</title> <para> - Ideally, you would probably want to be able to just tell the encoder to switch - into "high quality" mode and move on. - That would probably be nice, but unfortunately hard to implement as different - encoding options yield different quality results depending on the source material. - That is because compression depends on the visual properties of the video - in question. - For example, anime and live action have very different properties and - thus require different options to obtain optimum encoding. - The good news is that some options should never be left out, like - <option>mbd=2</option>, <option>trell</option>, and <option>v4mv</option>. - See below for a detailed description of common encoding options. +Ideally, you would probably want to be able to just tell the encoder to switch +into "high quality" mode and move on. +That would probably be nice, but unfortunately hard to implement as different +encoding options yield different quality results depending on the source +material. That is because compression depends on the visual properties of the +video in question. +For example, anime and live action have very different properties and +thus require different options to obtain optimum encoding. +The good news is that some options should never be left out, like +<option>mbd=2</option>, <option>trell</option>, and <option>v4mv</option>. +See below for a detailed description of common encoding options. </para> - <itemizedlist> <title>Options to adjust:</title> <listitem><para> @@ -2535,26 +2635,22 @@ An example with AC3 compression: option, but you need to deactivate scene detection, which is not a good idea as it will hurt encode efficiency a bit. </para></listitem> - <listitem><para> <emphasis role="bold">vb_strategy=1</emphasis>: helps in high-motion scenes. On some videos, vmax_b_frames may hurt quality, but vmax_b_frames=2 along with vb_strategy=1 helps. </para></listitem> - <listitem><para> <emphasis role="bold">dia</emphasis>: motion search range. Bigger is better and slower. Negative values are a completely different scale. Good values are -1 for a fast encode, or 2-4 for slower. </para></listitem> - <listitem><para> <emphasis role="bold">predia</emphasis>: motion search pre-pass. Not as important as dia. Good values are 1 (default) to 4. Requires preme=2 to really be useful. </para></listitem> - <listitem><para> <emphasis role="bold">cmp, subcmp, precmp</emphasis>: Comparison function for motion estimation. @@ -2564,19 +2660,16 @@ An example with AC3 compression: For cmp and subcmp, 2 is good for anime, and 3 is good for live action. 6 may or may not be slightly better, but is slow. </para></listitem> - <listitem><para> <emphasis role="bold">last_pred</emphasis>: Number of motion predictors to take from the previous frame. 1-3 or so help at little speed cost. Higher values are slow for no extra gain. </para></listitem> - <listitem><para> - <emphasis role="bold">cbp, mv0</emphasis>: Controls the selection of macroblocks. - Small speed cost for small quality gain. + <emphasis role="bold">cbp, mv0</emphasis>: Controls the selection of + macroblocks. Small speed cost for small quality gain. </para></listitem> - <listitem><para> <emphasis role="bold">qprd</emphasis>: adaptive quantization based on the macroblock's complexity. @@ -2584,7 +2677,6 @@ An example with AC3 compression: This can cause artifacts unless you set vqmax to some reasonably small value (6 is good, maybe as low as 4); vqmin=1 should also help. </para></listitem> - <listitem><para> <emphasis role="bold">qns</emphasis>: very slow, especially when combined with qprd. @@ -2593,7 +2685,6 @@ An example with AC3 compression: Do not use this unless you have already tweaked everything else as far as it will go and the results still are not good enough. </para></listitem> - <listitem><para> <emphasis role="bold">vqcomp</emphasis>: Tweak ratecontrol. What values are good depends on the movie. @@ -2602,7 +2693,6 @@ An example with AC3 compression: them on high-complexity scenes (default: 0.5, range: 0-1. recommended range: 0.5-0.7). </para></listitem> - <listitem><para> <emphasis role="bold">vlelim, vcelim</emphasis>: Sets the single coefficient elimination threshold for luminance and chroma planes. @@ -2614,7 +2704,6 @@ An example with AC3 compression: seem to be good for live movies, but seem not to help with anime; when encoding animation, you should probably leave them unchanged. </para></listitem> - <listitem><para> <emphasis role="bold">qpel</emphasis>: Quarter pixel motion estimation. MPEG-4 uses half pixel precision for its motion search by default, @@ -2625,13 +2714,11 @@ An example with AC3 compression: qpel always incurs a significant cost in CPU decode time (+25% in practice). </para></listitem> - <listitem><para> <emphasis role="bold">psnr</emphasis>: does not affect the actual encoding, but writes a log file giving the type/size/quality of each frame, and prints a summary of PSNR (Peak Signal to Noise Ratio) at the end. </para></listitem> - </itemizedlist> <itemizedlist> @@ -2639,7 +2726,6 @@ An example with AC3 compression: <listitem><para> <emphasis role="bold">vme</emphasis>: The default is best. </para></listitem> - <listitem><para> <emphasis role="bold">lumi_mask, dark_mask</emphasis>: Psychovisual adaptive quantization. @@ -2647,7 +2733,6 @@ An example with AC3 compression: Reasonable values may be effective in your case, but be warned this is very subjective. </para></listitem> - <listitem><para> <emphasis role="bold">scplx_mask</emphasis>: Tries to prevent blocky artifacts, but postprocessing is better. @@ -2655,31 +2740,38 @@ An example with AC3 compression: </itemizedlist> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-mpeg4-lavc-example-settings"> <title>Encoding setting examples</title> <para> - The following settings are examples of different encoding - option combinations that affect the speed vs quality tradeoff - at the same target bitrate. +The following settings are examples of different encoding +option combinations that affect the speed vs quality tradeoff +at the same target bitrate. </para> <para> - All the encoding settings were tested on a 720x448 @30000/1001 fps - video sample, the target bitrate was 900kbps, and the machine was an - AMD-64 3400+ at 2400 MHz in 64 bits mode. - Each encoding setting features the measured encoding speed (in - frames per second) and the PSNR loss (in dB) compared to the "very - high quality" setting. - Please understand that depending on your source, your machine type - and development advancements, you may get very different results. +All the encoding settings were tested on a 720x448 @30000/1001 fps +video sample, the target bitrate was 900kbps, and the machine was an +AMD-64 3400+ at 2400 MHz in 64 bits mode. +Each encoding setting features the measured encoding speed (in +frames per second) and the PSNR loss (in dB) compared to the "very +high quality" setting. +Please understand that depending on your source, your machine type +and development advancements, you may get very different results. </para> <para> <informaltable frame="all"> <tgroup cols="4"> <thead> -<row><entry>Description</entry><entry>Encoding options</entry><entry>speed (in fps)</entry><entry>Relative PSNR loss (in dB)</entry></row> +<row> + <entry>Description</entry> + <entry>Encoding options</entry> + <entry>speed (in fps)</entry> + <entry>Relative PSNR loss (in dB)</entry> +</row> </thead> <tbody> <row> @@ -2712,7 +2804,10 @@ An example with AC3 compression: </para> </sect2> -<sect2 id="custommatrices"><title>Custom inter/intra matrices</title> +<!-- ********** --> + +<sect2 id="custommatrices"> +<title>Custom inter/intra matrices</title> <para> With this feature of @@ -2761,202 +2856,204 @@ Inter: <para> Usage: <screen> -$ mencoder <replaceable>input.avi</replaceable> -o <replaceable>output.avi</replaceable> -oac copy -ovc lavc -lavcopts inter_matrix=...:intra_matrix=... +mencoder <replaceable>input.avi</replaceable> -o <replaceable>output.avi</replaceable> -oac copy -ovc lavc \ + -lavcopts inter_matrix=...:intra_matrix=... </screen> </para> <para> <screen> -$ mencoder <replaceable>input.avi</replaceable> -ovc lavc -lavcopts -vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37, -12,14,18,27,29,34,37,38,22,26,27,31,36,37,38,40,26,27,29,36,39,38,40,48,27, -29,34,37,38,40,48,58,29,34,37,38,40,48,58,69,34,37,38,40,48,58,69,79 -:inter_matrix=16,18,20,22,24,26,28,30,18,20,22,24,26,28,30,32,20,22,24,26, -28,30,32,34,22,24,26,30,32,32,34,36,24,26,28,32,34,34,36,38,26,28,30,32,34, +mencoder <replaceable>input.avi</replaceable> -ovc lavc -lavcopts \ +vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37,\ +12,14,18,27,29,34,37,38,22,26,27,31,36,37,38,40,26,27,29,36,39,38,40,48,27,\ +29,34,37,38,40,48,58,29,34,37,38,40,48,58,69,34,37,38,40,48,58,69,79\ +:inter_matrix=16,18,20,22,24,26,28,30,18,20,22,24,26,28,30,32,20,22,24,26,\ +28,30,32,34,22,24,26,30,32,32,34,36,24,26,28,32,34,34,36,38,26,28,30,32,34,\ 36,38,40,28,30,32,34,36,38,42,42,30,32,34,36,38,40,42,44 -oac copy -o svcd.mpg </screen> </para> </sect2> +<!-- ********** --> <sect2 id="menc-feat-dvd-mpeg4-example"> <title>Example</title> <para> - So, you have just bought your shiny new copy of Harry Potter and the Chamber - of Secrets (widescreen edition, of course), and you want to rip this DVD - so that you can add it to your Home Theatre PC. This is a region 1 DVD, - so it is NTSC. The example below will still apply to PAL, except you will - omit <option>-ofps 24000/1001</option> (because the output framerate is the - same as the input framerate), and of course the crop dimensions will be - different. +So, you have just bought your shiny new copy of Harry Potter and the Chamber +of Secrets (widescreen edition, of course), and you want to rip this DVD +so that you can add it to your Home Theatre PC. This is a region 1 DVD, +so it is NTSC. The example below will still apply to PAL, except you will +omit <option>-ofps 24000/1001</option> (because the output framerate is the +same as the input framerate), and of course the crop dimensions will be +different. </para> <para> - After running <option>mplayer dvd://1</option>, we follow the process - detailed in the section <link linkend="menc-feat-telecine">How to deal - with telecine and interlacing in NTSC DVDs</link> and discover that it is - 24000/1001 fps progressive video, which means that we need not use an inverse - telecine filter, such as <option>pullup</option> or - <option>filmdint</option>. +After running <option>mplayer dvd://1</option>, we follow the process +detailed in the section <link linkend="menc-feat-telecine">How to deal +with telecine and interlacing in NTSC DVDs</link> and discover that it is +24000/1001 fps progressive video, which means that we need not use an inverse +telecine filter, such as <option>pullup</option> or +<option>filmdint</option>. </para> <para> - Next, we want to determine the appropriate crop rectangle, so we use the - cropdetect filter: - - <screen>mplayer dvd://1 -vf cropdetect</screen> - - Make sure you seek to a fully filled frame (such as a bright scene), and - you will see in <application>MPlayer</application>'s console output: - - <screen>crop area: X: 0..719 Y: 57..419 (-vf crop=720:362:0:58)</screen> - - We then play the movie back with this filter to test its correctness: - - <screen>mplayer dvd://1 -vf crop=720:362:0:58</screen> - - And we see that it looks perfectly fine. Next, we ensure the width and - height are a multiple of 16. The width is fine, however the height is - not. Since we did not fail 7th grade math, we know that the nearest - multiple of 16 lower than 362 is 352. +Next, we want to determine the appropriate crop rectangle, so we use the +cropdetect filter: +<screen>mplayer dvd://1 -vf cropdetect</screen> +Make sure you seek to a fully filled frame (such as a bright scene), and +you will see in <application>MPlayer</application>'s console output: +<screen>crop area: X: 0..719 Y: 57..419 (-vf crop=720:362:0:58)</screen> +We then play the movie back with this filter to test its correctness: +<screen>mplayer dvd://1 -vf crop=720:362:0:58</screen> +And we see that it looks perfectly fine. Next, we ensure the width and +height are a multiple of 16. The width is fine, however the height is +not. Since we did not fail 7th grade math, we know that the nearest +multiple of 16 lower than 362 is 352. </para> <para> - We could just use <option>crop=720:352:0:58</option>, but it would be nice - to take a little off the top and a little off the bottom so that we - retain the center. We have shrunk the height by 10 pixels, but we do not - want to increase the y-offset by 5-pixels since that is an odd number and - will adversely affect quality. Instead, we will increase the y-offset by - 4 pixels: - - <screen>mplayer dvd://1 -vf crop=720:352:0:62</screen> - - Another reason to shave pixels from both the top and the bottom is that we - ensure we have eliminated any half-black pixels if they exist. Note that if - your video is telecined, make sure the <option>pullup</option> filter (or - whichever inverse telecine filter you decide to use) appears in the filter - chain before you crop. If it is interlaced, deinterlace before cropping. - (If you choose to preserve the interlaced video, then make sure your - vertical crop offset is a multiple of 4.) +We could just use <option>crop=720:352:0:58</option>, but it would be nice +to take a little off the top and a little off the bottom so that we +retain the center. We have shrunk the height by 10 pixels, but we do not +want to increase the y-offset by 5-pixels since that is an odd number and +will adversely affect quality. Instead, we will increase the y-offset by +4 pixels: +<screen>mplayer dvd://1 -vf crop=720:352:0:62</screen> +Another reason to shave pixels from both the top and the bottom is that we +ensure we have eliminated any half-black pixels if they exist. Note that if +your video is telecined, make sure the <option>pullup</option> filter (or +whichever inverse telecine filter you decide to use) appears in the filter +chain before you crop. If it is interlaced, deinterlace before cropping. +(If you choose to preserve the interlaced video, then make sure your +vertical crop offset is a multiple of 4.) </para> <para> - If you are really concerned about losing those 10 pixels, you might - prefer instead to scale the dimensions down to the nearest multiple of 16. - The filter chain would look like: - - <screen>-vf crop=720:362:0:58,scale=720:352</screen> - - Scaling the video down like this will mean that some small amount of - detail is lost, though it probably will not be perceptible. Scaling up will - result in lower quality (unless you increase the bitrate). Cropping - discards those pixels altogether. It is a tradeoff that you will want to - consider for each circumstance. For example, if the DVD video was made - for television, you might want to avoid vertical scaling, since the line - sampling corresponds to the way the content was originally recorded. +If you are really concerned about losing those 10 pixels, you might +prefer instead to scale the dimensions down to the nearest multiple of 16. +The filter chain would look like: +<screen>-vf crop=720:362:0:58,scale=720:352</screen> +Scaling the video down like this will mean that some small amount of +detail is lost, though it probably will not be perceptible. Scaling up will +result in lower quality (unless you increase the bitrate). Cropping +discards those pixels altogether. It is a tradeoff that you will want to +consider for each circumstance. For example, if the DVD video was made +for television, you might want to avoid vertical scaling, since the line +sampling corresponds to the way the content was originally recorded. </para> <para> - On inspection, we see that our movie has a fair bit of action and high - amounts of detail, so we pick 2400Kbit for our bitrate. +On inspection, we see that our movie has a fair bit of action and high +amounts of detail, so we pick 2400Kbit for our bitrate. </para> <para> - We are now ready to do the two pass encode. Pass one: - - <screen>mencoder dvd://1 -ofps 24000/1001 -oac copy -vf pullup,softskip,crop=720:352:0:62,hqdn3d=2:1:2 -ovc lavc \ --lavcopts vcodec=mpeg4:vbitrate=2400:v4mv:mbd=2:trell:cmp=3:subcmp=3:mbcmp=3:autoaspect:vpass=1 \ --o Harry_Potter_2.avi</screen> - - And pass two is the same, except that we specify <option>vpass=2</option>: - - <screen>mencoder dvd://1 -ofps 24000/1001 -oac copy -vf pullup,softskip,crop=720:352:0:62,hqdn3d=2:1:2 -ovc lavc \ --lavcopts vcodec=mpeg4:vbitrate=2400:v4mv:mbd=2:trell:cmp=3:subcmp=3:mbcmp=3:autoaspect:vpass=2 \ --o Harry_Potter_2.avi</screen> +We are now ready to do the two pass encode. Pass one: +<screen> +mencoder dvd://1 -ofps 24000/1001 -oac copy -o <replaceable>Harry_Potter_2.avi</replaceable> -ovc lavc \ + -lavcopts vcodec=mpeg4:vbitrate=2400:v4mv:mbd=2:trell:cmp=3:subcmp=3:mbcmp=3:autoaspect:vpass=1 \ + -vf pullup,softskip,crop=720:352:0:62,hqdn3d=2:1:2 +</screen> +And pass two is the same, except that we specify <option>vpass=2</option>: +<screen> +mencoder dvd://1 -ofps 24000/1001 -oac copy -o <replaceable>Harry_Potter_2.avi</replaceable> -ovc lavc \ + -lavcopts vcodec=mpeg4:vbitrate=2400:v4mv:mbd=2:trell:cmp=3:subcmp=3:mbcmp=3:autoaspect:vpass=2 \ + -vf pullup,softskip,crop=720:352:0:62,hqdn3d=2:1:2 +</screen> </para> <para> - The options <option>v4mv:mbd=2:trell</option> will greatly increase the - quality at the expense of encoding time. There is little reason to leave - these options out when the primary goal is quality. The options - <option>cmp=3:subcmp=3:mbcmp=3</option> select a comparison function that - yields higher quality than the defaults. You might try experimenting with - this parameter (refer to the man page for the possible values) as - different functions can have a large impact on quality depending on the - source material. For example, if you find - <systemitem class="library">libavcodec</systemitem> produces too much - blocky artifacting, you could try selecting the experimental NSSE as - comparison function via <option>*cmp=10</option>. +The options <option>v4mv:mbd=2:trell</option> will greatly increase the +quality at the expense of encoding time. There is little reason to leave +these options out when the primary goal is quality. The options +<option>cmp=3:subcmp=3:mbcmp=3</option> select a comparison function that +yields higher quality than the defaults. You might try experimenting with +this parameter (refer to the man page for the possible values) as +different functions can have a large impact on quality depending on the +source material. For example, if you find +<systemitem class="library">libavcodec</systemitem> produces too much +blocky artifacting, you could try selecting the experimental NSSE as +comparison function via <option>*cmp=10</option>. </para> <para> - For this movie, the resulting AVI will be 138 minutes long and nearly - 3GB. And because you said that file size does not matter, this is a - perfectly acceptable size. However, if you had wanted it smaller, you - could try a lower bitrate. Increasing bitrates have diminishing - returns, so while we might clearly see an improvement from 1800Kbit to - 2000Kbit, it might not be so noticeable above 2000Kbit. Feel - free to experiment until you are happy. +For this movie, the resulting AVI will be 138 minutes long and nearly +3GB. And because you said that file size does not matter, this is a +perfectly acceptable size. However, if you had wanted it smaller, you +could try a lower bitrate. Increasing bitrates have diminishing +returns, so while we might clearly see an improvement from 1800Kbit to +2000Kbit, it might not be so noticeable above 2000Kbit. Feel +free to experiment until you are happy. </para> <para> - Because we passed the source video through a denoise filter, you may want - to add some of it back during playback. This, along with the - <option>spp</option> post-processing filter, drastically improves the - perception of quality and helps eliminate blocky artifacts in the video. - With <application>MPlayer</application>'s <option>autoq</option> option, - you can vary the amount of post-processing done by the spp filter - depending on available CPU. Also, at this point, you may want to apply - gamma and/or color correction to best suit your display. For example: - - <screen>mplayer Harry_Potter_2.avi -vf spp,noise=9ah:5ah,eq2=1.2 -autoq 3</screen> - +Because we passed the source video through a denoise filter, you may want +to add some of it back during playback. This, along with the +<option>spp</option> post-processing filter, drastically improves the +perception of quality and helps eliminate blocky artifacts in the video. +With <application>MPlayer</application>'s <option>autoq</option> option, +you can vary the amount of post-processing done by the spp filter +depending on available CPU. Also, at this point, you may want to apply +gamma and/or color correction to best suit your display. For example: +<screen> +mplayer <replaceable>Harry_Potter_2.avi</replaceable> -vf spp,noise=9ah:5ah,eq2=1.2 -autoq 3 +</screen> </para> </sect2> </sect1> +<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --> + + <sect1 id="menc-feat-xvid"> <title>Encoding with the <systemitem class="library">Xvid</systemitem> -codec</title> + codec</title> + <para> - <systemitem class="library">Xvid</systemitem> is a free library for - encoding MPEG-4 ASP video streams. - Before starting to encode, you need to <link linkend="xvid"> - set up <application>MEncoder</application> to support it</link>. +<systemitem class="library">Xvid</systemitem> is a free library for +encoding MPEG-4 ASP video streams. +Before starting to encode, you need to <link linkend="xvid"> +set up <application>MEncoder</application> to support it</link>. </para> + <para> - This guide mainly aims at featuring the same kind of information - as x264's encoding guide. - Therefore, please begin by reading - <link linkend="menc-feat-x264-encoding-options-intro">the first part</link> - of that guide. +This guide mainly aims at featuring the same kind of information +as x264's encoding guide. +Therefore, please begin by reading +<link linkend="menc-feat-x264-encoding-options-intro">the first part</link> +of that guide. </para> +<!-- ********** --> <sect2 id="menc-feat-xvid-intro"> <title>What options should I use to get the best results?</title> <para> - Please begin by reviewing the - <systemitem class="library">Xvid</systemitem> section of - <application>MPlayer</application>'s man page. - This section is intended to be a supplement to the man page. +Please begin by reviewing the +<systemitem class="library">Xvid</systemitem> section of +<application>MPlayer</application>'s man page. +This section is intended to be a supplement to the man page. </para> + <para> - The Xvid default settings are already a good tradeoff between - speed and quality, therefore you can safely stick to them if - the following section puzzles you. +The Xvid default settings are already a good tradeoff between +speed and quality, therefore you can safely stick to them if +the following section puzzles you. </para> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-xvid-encoding-options"> <title>Encoding options of <systemitem class="library">Xvid</systemitem></title> <itemizedlist> <listitem><para> - <emphasis role="bold">vhq</emphasis> + <emphasis role="bold">vhq</emphasis> This setting affects the macroblock decision algorithm, where the higher the setting, the wiser the decision. The default setting may be safely used for every encode, while @@ -2967,16 +3064,14 @@ codec</title> Turning it off will noticeably speed up encoding; if speed is critical for you, the tradeoff may be worth it. </para></listitem> - <listitem><para> - <emphasis role="bold">bvhq</emphasis> + <emphasis role="bold">bvhq</emphasis> This does the same job as vhq, but does it on B-frames. It has a negligible impact on speed, and slightly improves quality (around +0.1dB PSNR). </para></listitem> - <listitem><para> - <emphasis role="bold">max_bframes</emphasis> + <emphasis role="bold">max_bframes</emphasis> A higher number of consecutive allowed B-frames usually improves compressibility, although it may also lead to more blocking artifacts. The default setting is a good tradeoff between compressibility and @@ -2986,9 +3081,8 @@ codec</title> target bitrate is high enough to ensure that the encoder does not have to increase quantizers to reach it. </para></listitem> - <listitem><para> - <emphasis role="bold">bf_threshold</emphasis> + <emphasis role="bold">bf_threshold</emphasis> This controls the B-frame sensitivity of the encoder, where a higher value leads to more B-frames being used (and vice versa). This setting is to be used together with <option>max_bframes</option>; @@ -3007,9 +3101,8 @@ codec</title> consecutive B-frame), this would be your only way to increase compressibility through using B-frames. </para></listitem> - <listitem><para> - <emphasis role="bold">trellis</emphasis> + <emphasis role="bold">trellis</emphasis> Optimizes the quantization process to get an optimal tradeoff between PSNR and bitrate, which allows significant bit saving. These bits will in return be spent elsewhere on the video, @@ -3019,7 +3112,6 @@ codec</title> have turned down <option>vhq</option> and all other more CPU-hungry options to the minimum. </para></listitem> - <listitem><para> <emphasis role="bold">hq_ac</emphasis> Activates a better coefficient cost estimation method, which slightly @@ -3027,32 +3119,31 @@ codec</title> than 0.01dB PSNR increase), while having a negligible impact on speed. It is therefore recommended to always leave it on. </para></listitem> - <listitem><para> <emphasis role="bold">cartoon</emphasis> Designed to better encode cartoon content, and has no impact on speed as it just tunes the mode decision heuristics for this type of content. </para></listitem> - -<listitem><para> - <emphasis role="bold">me_quality</emphasis> +<listitem> + <para> + <emphasis role="bold">me_quality</emphasis> This setting is to control the precision of the motion estimation. The higher <option>me_quality</option>, the more precise the estimation of the original motion will be, and the better the resulting clip will capture the original motion. - </para> - <para> + </para> + <para> The default setting is best in all cases; thus it is not recommended to turn it down unless you are really looking for speed, as all the bits saved by a good motion estimation would be spent elsewhere, raising overall quality. Therefore, do not go any lower than 5, and even that only as a last resort. -</para></listitem> - + </para> +</listitem> <listitem><para> - <emphasis role="bold">chroma_me</emphasis> + <emphasis role="bold">chroma_me</emphasis> Improves motion estimation by also taking the chroma (color) information into account, whereas <option>me_quality</option> alone only uses luma (grayscale). @@ -3062,73 +3153,75 @@ codec</title> If you are looking for speed, you should disable this option before starting to consider reducing <option>me_quality</option>. </para></listitem> - <listitem><para> <emphasis role="bold">chroma_opt</emphasis> - Is intended to increase chroma image quality around pure - white/black edges, rather than improving compression. - This can help to reduce the "red stairs" effect. + Is intended to increase chroma image quality around pure + white/black edges, rather than improving compression. + This can help to reduce the "red stairs" effect. </para></listitem> - <listitem><para> <emphasis role="bold">lumi_mask</emphasis> - Tries to give less bitrate to part of the picture that the - human eye cannot see very well, which should allow the encoder - to spend the saved bits on more important parts of the picture. - The quality of the encode yielded by this option highly depends - on personal preferences and on the type and monitor settings - used to watch it (typically, it will not look as good if it is - bright or if it is a TFT monitor). + Tries to give less bitrate to part of the picture that the + human eye cannot see very well, which should allow the encoder + to spend the saved bits on more important parts of the picture. + The quality of the encode yielded by this option highly depends + on personal preferences and on the type and monitor settings + used to watch it (typically, it will not look as good if it is + bright or if it is a TFT monitor). </para></listitem> - -<listitem><para> +<listitem> + <para> <emphasis role="bold">qpel</emphasis> - Raise the number of candidate motion vectors by increasing - the precision of the motion estimation from halfpel to - quarterpel. - The idea is to find better motion vectors which will in return - reduce bitrate (hence increasing quality). - However, motion vectors with quarterpel precision require a - few extra bits to code, but the candidate vectors do not always - give (much) better results. - Quite often, the codec still spends bits on the extra precision, - but little or no extra quality is gained in return. - Unfortunately, there is no way to foresee the possible gains of - <option>qpel</option>, so you need to actually encode with and - without it to know for sure. - </para><para> - <option>qpel</option> can be almost double encoding time, and - requires as much as 25% more processing power to decode. - It is not supported by all standalone players. -</para></listitem> - + Raise the number of candidate motion vectors by increasing + the precision of the motion estimation from halfpel to + quarterpel. + The idea is to find better motion vectors which will in return + reduce bitrate (hence increasing quality). + However, motion vectors with quarterpel precision require a + few extra bits to code, but the candidate vectors do not always + give (much) better results. + Quite often, the codec still spends bits on the extra precision, + but little or no extra quality is gained in return. + Unfortunately, there is no way to foresee the possible gains of + <option>qpel</option>, so you need to actually encode with and + without it to know for sure. + </para> + <para> + <option>qpel</option> can be almost double encoding time, and + requires as much as 25% more processing power to decode. + It is not supported by all standalone players. + </para> +</listitem> <listitem><para> <emphasis role="bold">gmc</emphasis> - Tries to save bits on panning scenes by using a single motion - vector for the whole frame. - This almost always raises PSNR, but significantly slows down - encoding (as well as decoding). - Therefore, you should only use it when you have turned - <option>vhq</option> to the maximum. - <systemitem class="library">Xvid</systemitem>'s GMC is more - sophisticated than DivX's, but is only supported by few - standalone players. + Tries to save bits on panning scenes by using a single motion + vector for the whole frame. + This almost always raises PSNR, but significantly slows down + encoding (as well as decoding). + Therefore, you should only use it when you have turned + <option>vhq</option> to the maximum. + <systemitem class="library">Xvid</systemitem>'s GMC is more + sophisticated than DivX's, but is only supported by few + standalone players. </para></listitem> - </itemizedlist> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-xvid-encoding-profiles"> <title>Encoding profiles</title> + <para> - Xvid supports encoding profiles through the <option>profile</option> option, - which are used to impose restrictions on the properties of the Xvid video - stream such that it will be playable on anything which supports the - chosen profile. - The restrictions relate to resolutions, bitrates and certain MPEG-4 - features. - The following table shows what each profile supports. +Xvid supports encoding profiles through the <option>profile</option> option, +which are used to impose restrictions on the properties of the Xvid video +stream such that it will be playable on anything which supports the +chosen profile. +The restrictions relate to resolutions, bitrates and certain MPEG-4 +features. +The following table shows what each profile supports. </para> + <informaltable> <tgroup cols="16" align="center"> <colspec colnum="1" colname="col1"/> @@ -3151,267 +3244,268 @@ codec</title> <spanspec spanname="spa2-5" namest="col2" nameend="col5"/> <spanspec spanname="spa6-11" namest="col6" nameend="col11"/> <spanspec spanname="spa12-17" namest="col12" nameend="col17"/> - <tbody> - <row> - <entry></entry> - <entry spanname="spa2-5">Simple</entry> - <entry spanname="spa6-11">Advanced Simple</entry> - <entry spanname="spa12-17">DivX</entry> - </row> - <row> - <entry>Profile name</entry> - <entry>0</entry> - <entry>1</entry> - <entry>2</entry> - <entry>3</entry> - <entry>0</entry> - <entry>1</entry> - <entry>2</entry> - <entry>3</entry> - <entry>4</entry> - <entry>5</entry> - <entry>Handheld</entry> - <entry>Portable NTSC</entry> - <entry>Portable PAL</entry> - <entry>Home Theater NTSC</entry> - <entry>Home Theater PAL</entry> - <entry>HDTV</entry> - </row> - <row> - <entry>Width [pixels]</entry> - <entry>176</entry> - <entry>176</entry> - <entry>352</entry> - <entry>352</entry> - <entry>176</entry> - <entry>176</entry> - <entry>352</entry> - <entry>352</entry> - <entry>352</entry> - <entry>720</entry> - <entry>176</entry> - <entry>352</entry> - <entry>352</entry> - <entry>720</entry> - <entry>720</entry> - <entry>1280</entry> - </row> - <row> - <entry>Height [pixels]</entry> - <entry>144</entry> - <entry>144</entry> - <entry>288</entry> - <entry>288</entry> - <entry>144</entry> - <entry>144</entry> - <entry>288</entry> - <entry>288</entry> - <entry>576</entry> - <entry>576</entry> - <entry>144</entry> - <entry>240</entry> - <entry>288</entry> - <entry>480</entry> - <entry>576</entry> - <entry>720</entry> - </row> - <row> - <entry>Frame rate [fps]</entry> - <entry>15</entry> - <entry>15</entry> - <entry>15</entry> - <entry>15</entry> - <entry>30</entry> - <entry>30</entry> - <entry>15</entry> - <entry>30</entry> - <entry>30</entry> - <entry>30</entry> - <entry>15</entry> - <entry>30</entry> - <entry>25</entry> - <entry>30</entry> - <entry>25</entry> - <entry>30</entry> - </row> - <row> - <entry>Max average bitrate [kbps]</entry> - <entry>64</entry> - <entry>64</entry> - <entry>128</entry> - <entry>384</entry> - <entry>128</entry> - <entry>128</entry> - <entry>384</entry> - <entry>768</entry> - <entry>3000</entry> - <entry>8000</entry> - <entry>537.6</entry> - <entry>4854</entry> - <entry>4854</entry> - <entry>4854</entry> - <entry>4854</entry> - <entry>9708.4</entry> - </row> - <row> - <entry>Peak average bitrate over 3 secs [kbps]</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>800</entry> - <entry>8000</entry> - <entry>8000</entry> - <entry>8000</entry> - <entry>8000</entry> - <entry>16000</entry> - </row> - <row> - <entry>Max. B-frames</entry> - <entry>0</entry> - <entry>0</entry> - <entry>0</entry> - <entry>0</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>0</entry> - <entry>1</entry> - <entry>1</entry> - <entry>1</entry> - <entry>1</entry> - <entry>2</entry> - </row> - <row> - <entry>MPEG quantization</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - </row> - <row> - <entry>Adaptive quantization</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - </row> - <row> - <entry>Interlaced encoding</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - </row> - <row> - <entry>Quaterpixel</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - </row> - <row> - <entry>Global motion compensation</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry>X</entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - <entry></entry> - </row> - </tbody> +<tbody> +<row> + <entry></entry> + <entry spanname="spa2-5">Simple</entry> + <entry spanname="spa6-11">Advanced Simple</entry> + <entry spanname="spa12-17">DivX</entry> +</row> +<row> + <entry>Profile name</entry> + <entry>0</entry> + <entry>1</entry> + <entry>2</entry> + <entry>3</entry> + <entry>0</entry> + <entry>1</entry> + <entry>2</entry> + <entry>3</entry> + <entry>4</entry> + <entry>5</entry> + <entry>Handheld</entry> + <entry>Portable NTSC</entry> + <entry>Portable PAL</entry> + <entry>Home Theater NTSC</entry> + <entry>Home Theater PAL</entry> + <entry>HDTV</entry> +</row> +<row> + <entry>Width [pixels]</entry> + <entry>176</entry> + <entry>176</entry> + <entry>352</entry> + <entry>352</entry> + <entry>176</entry> + <entry>176</entry> + <entry>352</entry> + <entry>352</entry> + <entry>352</entry> + <entry>720</entry> + <entry>176</entry> + <entry>352</entry> + <entry>352</entry> + <entry>720</entry> + <entry>720</entry> + <entry>1280</entry> +</row> +<row> + <entry>Height [pixels]</entry> + <entry>144</entry> + <entry>144</entry> + <entry>288</entry> + <entry>288</entry> + <entry>144</entry> + <entry>144</entry> + <entry>288</entry> + <entry>288</entry> + <entry>576</entry> + <entry>576</entry> + <entry>144</entry> + <entry>240</entry> + <entry>288</entry> + <entry>480</entry> + <entry>576</entry> + <entry>720</entry> +</row> +<row> + <entry>Frame rate [fps]</entry> + <entry>15</entry> + <entry>15</entry> + <entry>15</entry> + <entry>15</entry> + <entry>30</entry> + <entry>30</entry> + <entry>15</entry> + <entry>30</entry> + <entry>30</entry> + <entry>30</entry> + <entry>15</entry> + <entry>30</entry> + <entry>25</entry> + <entry>30</entry> + <entry>25</entry> + <entry>30</entry> +</row> +<row> + <entry>Max average bitrate [kbps]</entry> + <entry>64</entry> + <entry>64</entry> + <entry>128</entry> + <entry>384</entry> + <entry>128</entry> + <entry>128</entry> + <entry>384</entry> + <entry>768</entry> + <entry>3000</entry> + <entry>8000</entry> + <entry>537.6</entry> + <entry>4854</entry> + <entry>4854</entry> + <entry>4854</entry> + <entry>4854</entry> + <entry>9708.4</entry> +</row> +<row> + <entry>Peak average bitrate over 3 secs [kbps]</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>800</entry> + <entry>8000</entry> + <entry>8000</entry> + <entry>8000</entry> + <entry>8000</entry> + <entry>16000</entry> +</row> +<row> + <entry>Max. B-frames</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry>0</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>0</entry> + <entry>1</entry> + <entry>1</entry> + <entry>1</entry> + <entry>1</entry> + <entry>2</entry> +</row> +<row> + <entry>MPEG quantization</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> +</row> +<row> + <entry>Adaptive quantization</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> +</row> +<row> + <entry>Interlaced encoding</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> +</row> +<row> + <entry>Quaterpixel</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> +</row> +<row> + <entry>Global motion compensation</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry>X</entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> + <entry></entry> +</row> +</tbody> </tgroup> </informaltable> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-xvid-example-settings"> <title>Encoding setting examples</title> <para> - The following settings are examples of different encoding - option combinations that affect the speed vs quality tradeoff - at the same target bitrate. +The following settings are examples of different encoding +option combinations that affect the speed vs quality tradeoff +at the same target bitrate. </para> <para> - All the encoding settings were tested on a 720x448 @30000/1001 fps - video sample, the target bitrate was 900kbps, and the machine was an - AMD-64 3400+ at 2400 MHz in 64 bits mode. - Each encoding setting features the measured encoding speed (in - frames per second) and the PSNR loss (in dB) compared to the "very - high quality" setting. - Please understand that depending on your source, your machine type - and development advancements, you may get very different results. +All the encoding settings were tested on a 720x448 @30000/1001 fps +video sample, the target bitrate was 900kbps, and the machine was an +AMD-64 3400+ at 2400 MHz in 64 bits mode. +Each encoding setting features the measured encoding speed (in +frames per second) and the PSNR loss (in dB) compared to the "very +high quality" setting. +Please understand that depending on your source, your machine type +and development advancements, you may get very different results. </para> -<para> <informaltable frame="all"> <tgroup cols="4"> <thead> @@ -3445,91 +3539,104 @@ codec</title> </tbody> </tgroup> </informaltable> -</para> </sect2> - </sect1> + +<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --> + + <sect1 id="menc-feat-x264"> -<title>Encoding with the <systemitem class="library">x264</systemitem> codec</title> +<title>Encoding with the + <systemitem class="library">x264</systemitem> codec</title> + <para> - <systemitem class="library">x264</systemitem> is a free library for - encoding H.264/AVC video streams. - Before starting to encode, you need to <link linkend="codec-x264-encode"> - set up <application>MEncoder</application> to support it</link>. +<systemitem class="library">x264</systemitem> is a free library for +encoding H.264/AVC video streams. +Before starting to encode, you need to +<link linkend="codec-x264-encode">set up <application>MEncoder</application> to support it</link>. </para> +<!-- ********** --> + <sect2 id="menc-feat-x264-encoding-options"> <title>Encoding options of x264</title> <para> - Please begin by reviewing the - <systemitem class="library">x264</systemitem> section of - <application>MPlayer</application>'s man page. - This section is intended to be a supplement to the man page. - Here you will find quick hints about which options are most - likely to interest most people. The man page is more terse, - but also more exhaustive, and it sometimes offers much better - technical detail. +Please begin by reviewing the +<systemitem class="library">x264</systemitem> section of +<application>MPlayer</application>'s man page. +This section is intended to be a supplement to the man page. +Here you will find quick hints about which options are most +likely to interest most people. The man page is more terse, +but also more exhaustive, and it sometimes offers much better +technical detail. </para> + <sect3 id="menc-feat-x264-encoding-options-intro"> <title>Introduction</title> -<para>This guide considers two major categories of encoding options:</para> + +<para> +This guide considers two major categories of encoding options: +</para> <orderedlist> - <listitem><para>Options which mainly trade off encoding time vs. quality - </para></listitem> - <listitem><para>Options which may be useful for fulfilling various personal - preferences and special requirements</para></listitem> +<listitem><para> + Options which mainly trade off encoding time vs. quality +</para></listitem> +<listitem><para> + Options which may be useful for fulfilling various personal + preferences and special requirements +</para></listitem> </orderedlist> <para> - Ultimately, only you can decide which options are best for your - purposes. The decision for the first class of options is the simplest: - you only have to decide whether you think the quality differences - justify the speed differences. For the second class of options, - preferences may be far more subjective, and more factors may be - involved. Note that some of the "personal preferences and special - requirements" options can still have large impacts on speed or quality, - but that is not what they are primarily useful for. A couple of the - "personal preference" options may even cause changes that look better - to some people, but look worse to others. +Ultimately, only you can decide which options are best for your +purposes. The decision for the first class of options is the simplest: +you only have to decide whether you think the quality differences +justify the speed differences. For the second class of options, +preferences may be far more subjective, and more factors may be +involved. Note that some of the "personal preferences and special +requirements" options can still have large impacts on speed or quality, +but that is not what they are primarily useful for. A couple of the +"personal preference" options may even cause changes that look better +to some people, but look worse to others. </para> <para> - Before continuing, you need to understand that this guide uses only one - quality metric: global PSNR. - For a brief explanation of what PSNR is, see - <ulink url="http://en.wikipedia.org/wiki/PSNR">the Wikipedia article on PSNR</ulink>. - Global PSNR is the last PSNR number reported when you include - the <option>psnr</option> option in <option>x264encopts</option>. - Any time you read a claim about PSNR, one of the assumptions - behind the claim is that equal bitrates are used. +Before continuing, you need to understand that this guide uses only one +quality metric: global PSNR. +For a brief explanation of what PSNR is, see +<ulink url="http://en.wikipedia.org/wiki/PSNR">the Wikipedia article on PSNR</ulink>. +Global PSNR is the last PSNR number reported when you include +the <option>psnr</option> option in <option>x264encopts</option>. +Any time you read a claim about PSNR, one of the assumptions +behind the claim is that equal bitrates are used. </para> <para> - Nearly all of this guide's comments assume you are using - two pass. - When comparing options, there are two major reasons for using - two pass encoding. - First, using two pass often gains around 1dB PSNR, which is a - very big difference. - Secondly, testing options by doing direct quality comparisons - with one pass encodes introduces a major confounding - factor: bitrate often varies significantly with each encode. - It is not always easy to tell whether quality changes are due - mainly to changed options, or if they mostly reflect essentially - random differences in the achieved bitrate. +Nearly all of this guide's comments assume you are using two pass. +When comparing options, there are two major reasons for using +two pass encoding. +First, using two pass often gains around 1dB PSNR, which is a +very big difference. +Secondly, testing options by doing direct quality comparisons +with one pass encodes introduces a major confounding +factor: bitrate often varies significantly with each encode. +It is not always easy to tell whether quality changes are due +mainly to changed options, or if they mostly reflect essentially +random differences in the achieved bitrate. </para> - </sect3> + <sect3 id="menc-feat-x264-encoding-options-speedvquality"> <title>Options which primarily affect speed and quality</title> <itemizedlist> -<listitem><para> +<listitem> + <para> <emphasis role="bold">subq</emphasis>: Of the options which allow you to trade off speed for quality, <option>subq</option> and <option>frameref</option> (see below) are usually @@ -3548,8 +3655,8 @@ codec</title> Typically, <option>subq=5</option> achieves 0.2-0.5 dB higher global PSNR in comparison <option>subq=1</option>. This is usually enough to be visible. -</para> -<para> + </para> + <para> <option>subq=6</option> is the slowest, highest quality mode. In comparison to <option>subq=5</option>, it usually gains 0.1-0.4 dB global PSNR with speed costs varying from 25%-100%. @@ -3561,18 +3668,17 @@ codec</title> and quality in complex, high motion scenes, but it may not have much effect in low-motion scenes. Note that it is still recommended to always set <option>bframes</option> to something other than zero (see below). -</para></listitem> -<listitem><para> + </para> +</listitem> +<listitem> + <para> <emphasis role="bold">frameref</emphasis>: <option>frameref</option> is set to 1 by default, but this - should not be taken to imply that it is reasonable to set it - to 1. + should not be taken to imply that it is reasonable to set it to 1. Merely raising <option>frameref</option> to 2 gains around - 0.15dB PSNR with a 5-10% speed penalty; this seems like a - good tradeoff. + 0.15dB PSNR with a 5-10% speed penalty; this seems like a good tradeoff. <option>frameref=3</option> gains around 0.25dB PSNR over - <option>frameref=1</option>, which should be a visible - difference. + <option>frameref=1</option>, which should be a visible difference. <option>frameref=3</option> is around 15% slower than <option>frameref=1</option>. Unfortunately, diminishing returns set in rapidly. @@ -3581,8 +3687,7 @@ codec</title> 15% speed penalty. Above <option>frameref=6</option>, the quality gains are usually very small (although you should keep in mind throughout - this whole discussion that it can vary quite a lot depending on - your source). + this whole discussion that it can vary quite a lot depending on your source). In a fairly typical case, <option>frameref=12</option> will improve global PSNR by a tiny 0.02dB over <option>frameref=6</option>, at a speed cost of 15%-20%. @@ -3591,9 +3696,9 @@ codec</title> almost certainly never <emphasis role="bold">harm</emphasis> PSNR, but the additional quality benefits are barely even measurable, let alone perceptible. -</para> -<note><title>Note:</title> -<para> + </para> + <note><title>Note:</title> + <para> Raising <option>frameref</option> to unnecessarily high values <emphasis role="bold">can</emphasis> and <emphasis role="bold">usually does</emphasis> @@ -3602,9 +3707,8 @@ codec</title> <option>frameref</option> "too high" currently seems too remote to even worry about, and in the future, optimizations may remove the possibility altogether. -</para> -</note> -<para> + </para></note> + <para> If you care about speed, a reasonable compromise is to use low <option>subq</option> and <option>frameref</option> values on the first pass, and then raise them on the second pass. @@ -3624,9 +3728,10 @@ codec</title> <option>frameref</option> to 3 or higher. This issue is probably extremely rare in live action video material, but it does sometimes come up in video game captures. -</para></listitem> - -<listitem><para> + </para> +</listitem> +<listitem> + <para> <emphasis role="bold">me</emphasis>: This option is for choosing the motion estimation search method. Altering this option provides a straightforward quality-vs-speed @@ -3640,13 +3745,12 @@ codec</title> is about 40% slower than the default <option> me=hex</option>. With <option>frameref=3</option>, the speed penalty incurred drops to 25%-30%. -</para> -<para> + </para> + <para> <option>me=esa</option> uses an exhaustive search that is too slow for practical use. -</para> + </para> </listitem> - <listitem><para> <emphasis role="bold">partitions=all</emphasis>: This option enables the use of 8x4, 4x8 and 4x4 subpartitions in @@ -3656,10 +3760,9 @@ codec</title> containing only low motion, however in some high-motion source, particularly source with lots of small moving objects, gains of about 0.1dB can be expected. -</para> -</listitem> - -<listitem><para> +</para></listitem> +<listitem> + <para> <emphasis role="bold">bframes</emphasis>: If you are used to encoding with other codecs, you may have found that B-frames are not always useful. @@ -3670,8 +3773,8 @@ codec</title> It is interesting to note that using B-frames usually speeds up the second pass somewhat, and may also speed up a single pass encode if adaptive B-frame decision is turned off. -</para> -<para> + </para> + <para> With adaptive B-frame decision turned off (<option>x264encopts</option>'s <option>nob_adapt</option>), the optimal value for this setting is usually no more than @@ -3681,13 +3784,14 @@ codec</title> B-frames in scenes where they would hurt compression. The encoder rarely chooses to use more than 3 or 4 B-frames; setting this option any higher will have little effect. -</para></listitem> - -<listitem><para> + </para> +</listitem> +<listitem> + <para> <emphasis role="bold">b_adapt</emphasis>: Note: This is on by default. -</para> -<para> + </para> + <para> With this option enabled, the encoder will use a reasonably fast decision process to reduce the number of B-frames used in scenes that might not benefit from them as much. @@ -3700,8 +3804,8 @@ codec</title> first pass. <option>b_adapt</option> and <option>b_bias</option> have no effect on subsequent passes. -</para></listitem> - + </para> +</listitem> <listitem><para> <emphasis role="bold">b_pyramid</emphasis>: You might as well enable this option if you are using >=2 B-frames; @@ -3710,8 +3814,8 @@ codec</title> Note that these videos cannot be read by libavcodec-based decoders older than about March 5, 2005. </para></listitem> - -<listitem><para> +<listitem> + <para> <emphasis role="bold">weight_b</emphasis>: In typical cases, there is not much gain with this option. However, in crossfades or fade-to-black scenes, weighted @@ -3724,22 +3828,26 @@ codec</title> Also, contrary to what some people seem to guess, the decoder CPU requirements are not much affected by weighted prediction, all else being equal. -</para> -<para> + </para> + <para> Unfortunately, the current adaptive B-frame decision algorithm has a strong tendency to avoid B-frames during fades. Until this changes, it may be a good idea to add <option>nob_adapt</option> to your x264encopts, if you expect fades to have a large effect in your particular video clip. -</para></listitem> + </para> +</listitem> </itemizedlist> </sect3> + <sect3 id="menc-feat-x264-encoding-options-misc-preferences"> <title>Options pertaining to miscellaneous preferences</title> + <itemizedlist> -<listitem><para> +<listitem> + <para> <emphasis role="bold">Two pass encoding</emphasis>: Above, it was suggested to always use two pass encoding, but there are still reasons for not using it. For instance, if you are capturing @@ -3747,8 +3855,8 @@ codec</title> Also, one pass is obviously faster than two passes; if you use the exact same set of options on both passes, two pass encoding is almost twice as slow. -</para> -<para> + </para> + <para> Still, there are very good reasons for using two pass encoding. For one thing, single pass ratecontrol is not psychic, and it often makes unreasonable choices because it cannot see the big picture. For example, @@ -3772,8 +3880,8 @@ codec</title> it would have taken to make it look decent. There are ways to mitigate the pitfalls of single-pass encoding, but they may tend to increase bitrate misprediction. -</para> -<para> + </para> + <para> Multipass ratecontrol can offer huge advantages over a single pass. Using the statistics gathered from the first pass encode, the encoder can estimate, with reasonable accuracy, the "cost" (in bits) of @@ -3782,8 +3890,8 @@ codec</title> expensive (high-motion) and cheap (low-motion) scenes. See <option>qcomp</option> below for some ideas on how to tweak this allocation to your liking. -</para> -<para> + </para> + <para> Moreover, two passes need not take twice as long as one pass. You can tweak the options in the first pass for higher speed and lower quality. If you choose your options well, you can get a very fast first pass. @@ -3794,10 +3902,10 @@ codec</title> <option>x264encopts</option>. Then, on the second pass, use slower, higher-quality options: <option>subq=6:frameref=15:partitions=all:me=umh</option> -</para></listitem> + </para> +</listitem> <listitem><para> <emphasis role="bold">Three pass encoding</emphasis>? - x264 offers the ability to make an arbitrary number of consecutive passes. If you specify <option>pass=1</option> on the first pass, then use <option>pass=3</option> on a subsequent pass, the subsequent @@ -3813,7 +3921,6 @@ codec</title> also a few special cases in which three (or more) passes are handy for advanced users, but for brevity, this guide omits discussing those special cases. - </para></listitem> <listitem><para> <emphasis role="bold">qcomp</emphasis>: @@ -3845,11 +3952,12 @@ codec</title> vanishingly low, or even zero). The video stream will still have seekable points as long as there are some scene changes. </para></listitem> -<listitem><para> +<listitem> + <para> <emphasis role="bold">deblock</emphasis>: This topic is going to be a bit controversial. -</para> -<para> + </para> + <para> H.264 defines a simple deblocking procedure on I-blocks that uses pre-set strengths and thresholds depending on the QP of the block in question. @@ -3858,17 +3966,17 @@ codec</title> The pre-set strengths defined by the standard are well-chosen and the odds are very good that they are PSNR-optimal for whatever video you are trying to encode. - The <option>deblock</option> allow you to specify offsets to the preset deblocking - thresholds. -</para> -<para> + The <option>deblock</option> allow you to specify offsets to the preset + deblocking thresholds. + </para> + <para> Many people seem to think it is a good idea to lower the deblocking filter strength by large amounts (say, -3). This is however almost never a good idea, and in most cases, people who are doing this do not understand very well how deblocking works by default. -</para> -<para> + </para> + <para> The first and most important thing to know about the in-loop deblocking filter is that the default thresholds are almost always PSNR-optimal. @@ -3878,8 +3986,8 @@ codec</title> guaranteed to hurt PSNR. Strengthening the filter will smear more details; weakening the filter will increase the appearance of blockiness. -</para> -<para> + </para> + <para> It is definitely a bad idea to lower the deblocking thresholds if your source is mainly low in spacial complexity (i.e., not a lot of detail or noise). @@ -3896,9 +4004,8 @@ codec</title> By lowering the deblocking filter strength, you are most likely increasing error by adding ringing artifacts, but the eye does not notice because it confuses the artifacts with detail. -</para> - -<para> + </para> + <para> This <emphasis role="bold">still</emphasis> does not justify lowering the deblocking filter strength, however. You can generally get better quality noise from postprocessing. @@ -3908,36 +4015,43 @@ codec</title> artifacting. It will almost certainly look better than the results you would have gotten just by fiddling with the deblocking filter. -</para></listitem> + </para> +</listitem> </itemizedlist> </sect3> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-x264-example-settings"> <title>Encoding setting examples</title> <para> - The following settings are examples of different encoding - option combinations that affect the speed vs quality tradeoff - at the same target bitrate. +The following settings are examples of different encoding +option combinations that affect the speed vs quality tradeoff +at the same target bitrate. </para> <para> - All the encoding settings were tested on a 720x448 @30000/1001 fps - video sample, the target bitrate was 900kbps, and the machine was an - AMD-64 3400+ at 2400 MHz in 64 bits mode. - Each encoding setting features the measured encoding speed (in - frames per second) and the PSNR loss (in dB) compared to the "very - high quality" setting. - Please understand that depending on your source, your machine type - and development advancements, you may get very different results. +All the encoding settings were tested on a 720x448 @30000/1001 fps +video sample, the target bitrate was 900kbps, and the machine was an +AMD-64 3400+ at 2400 MHz in 64 bits mode. +Each encoding setting features the measured encoding speed (in +frames per second) and the PSNR loss (in dB) compared to the "very +high quality" setting. +Please understand that depending on your source, your machine type +and development advancements, you may get very different results. </para> -<para> <informaltable frame="all"> <tgroup cols="4"> <thead> -<row><entry>Description</entry><entry>Encoding options</entry><entry>speed (in fps)</entry><entry>Relative PSNR loss (in dB)</entry></row> +<row> + <entry>Description</entry> + <entry>Encoding options</entry> + <entry>speed (in fps)</entry> + <entry>Relative PSNR loss (in dB)</entry> +</row> </thead> <tbody> <row> @@ -3961,18 +4075,24 @@ codec</title> </tbody> </tgroup> </informaltable> -</para> </sect2> - </sect1> + +<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --> + + <sect1 id="menc-feat-video-for-windows"> -<title>Encoding with the <systemitem class="library">Video For Windows</systemitem> codec family</title> +<title> + Encoding with the <systemitem class="library">Video For Windows</systemitem> + codec family +</title> <para> Video for Windows provides simple encoding by means of binary video codecs. You can encode with the following codecs (if you have more, please tell us!) </para> + <para> Note that support for this is very experimental and some codecs may not work correctly. Some codecs will only work in certain colorspaces, try @@ -3980,6 +4100,8 @@ correctly. Some codecs will only work in certain colorspaces, try if a codec fails or gives wrong output. </para> +<!-- ********** --> + <sect2 id="menc-feat-enc-vfw-video-codecs"> <title>Video for Windows supported codecs</title> @@ -3988,10 +4110,10 @@ if a codec fails or gives wrong output. <tgroup cols="4"> <thead> <row> -<entry>Video codec file name</entry> -<entry>Description (FourCC)</entry> -<entry>md5sum</entry> -<entry>Comment</entry> + <entry>Video codec file name</entry> + <entry>Description (FourCC)</entry> + <entry>md5sum</entry> + <entry>Comment</entry> </row> </thead> <tbody> @@ -4102,8 +4224,8 @@ if a codec fails or gives wrong output. <entry>MSU Lossless codec (MSUD)</entry> <entry>294bf9288f2f127bb86f00bfcc9ccdda</entry> <entry> - Decodable by <application>Window Media Player</application>, - not <application>MPlayer</application> (yet). + Decodable by <application>Window Media Player</application>, + not <application>MPlayer</application> (yet). </entry> </row> <row> @@ -4117,343 +4239,350 @@ if a codec fails or gives wrong output. </informaltable> The first column contains the codec names that should be passed after the -<literal>codec</literal> parameter, like: <option>-xvfwopts codec=divx.dll</option> +<literal>codec</literal> parameter, +like: <option>-xvfwopts codec=divx.dll</option> The FourCC code used by each codec is given in the parentheses. </para> + <informalexample> <para> An example with VP3 compression: -<screen>mencoder dvd://2 -o title2.avi -ovc vfw -xvfwopts codec=vp31vfw.dll -oac copy</screen> +<screen> +mencoder dvd://2 -o <replaceable>title2.avi</replaceable> -ovc vfw -xvfwopts codec=vp31vfw.dll -oac copy +</screen> </para> </informalexample> </sect2> </sect1> +<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --> + + <sect1 id="menc-feat-vcd-dvd"> -<title>Using <application>MEncoder</application> to create VCD/SVCD/DVD-compliant files.</title> +<title>Using <application>MEncoder</application> + to create VCD/SVCD/DVD-compliant files</title> <sect2 id="menc-feat-vcd-dvd-constraints"> <title>Format Constraints</title> + <para> - <application>MEncoder</application> is capable of creating VCD, SCVD - and DVD format MPEG files using the - <systemitem class="library">libavcodec</systemitem> library. - These files can then be used in conjunction with - <ulink url="http://www.gnu.org/software/vcdimager/vcdimager.html">vcdimager</ulink> - or - <ulink url="http://dvdauthor.sourceforge.net/">dvdauthor</ulink> - to create discs that will play on a standard set-top player. +<application>MEncoder</application> is capable of creating VCD, SCVD +and DVD format MPEG files using the +<systemitem class="library">libavcodec</systemitem> library. +These files can then be used in conjunction with +<ulink url="http://www.gnu.org/software/vcdimager/vcdimager.html">vcdimager</ulink> +or +<ulink url="http://dvdauthor.sourceforge.net/">dvdauthor</ulink> +to create discs that will play on a standard set-top player. </para> <para> - The DVD, SVCD, and VCD formats are subject to heavy constraints. - Only a small selection of encoded picture sizes and aspect ratios are - available. - If your movie does not already meet these requirements, you may have - to scale,crop or add black borders to the picture to make it - compliant. +The DVD, SVCD, and VCD formats are subject to heavy constraints. +Only a small selection of encoded picture sizes and aspect ratios are +available. +If your movie does not already meet these requirements, you may have +to scale,crop or add black borders to the picture to make it +compliant. </para> + <sect3 id="menc-feat-vcd-dvd-constraints-resolution"> <title>Format Constraints</title> <informaltable frame="all"> <tgroup cols="9"> <thead> - <row> - <entry>Format</entry> - <entry>Resolution</entry> - <entry>V. Codec</entry> - <entry>V. Bitrate</entry> - <entry>Sample Rate</entry> - <entry>A. Codec</entry> - <entry>A. Bitrate</entry> - <entry>FPS</entry> - <entry>Aspect</entry> - </row> +<row> + <entry>Format</entry> + <entry>Resolution</entry> + <entry>V. Codec</entry> + <entry>V. Bitrate</entry> + <entry>Sample Rate</entry> + <entry>A. Codec</entry> + <entry>A. Bitrate</entry> + <entry>FPS</entry> + <entry>Aspect</entry> +</row> </thead> <tbody> - <row> - <entry>NTSC DVD</entry> - <entry>720x480, 704x480, 352x480, 352x240</entry> - <entry>MPEG-2</entry> - <entry>9800 kbps</entry> - <entry>48000 Hz</entry> - <entry>AC3,PCM</entry> - <entry>1536 kbps (max)</entry> - <entry>30000/1001, 24000/1001</entry> - <entry>4:3, 16:9 (only for 720x480)</entry> - </row> - <row> - <entry>NTSC DVD</entry> - <entry>352x240<footnote id='fn-rare-resolutions'><para> - These resolutions are rarely used for DVDs because - they are fairly low quality.</para></footnote></entry> - <entry>MPEG-1</entry> - <entry>1856 kbps</entry> - <entry>48000 Hz</entry> - <entry>AC3,PCM</entry> - <entry>1536 kbps (max)</entry> - <entry>30000/1001, 24000/1001</entry> - <entry>4:3, 16:9</entry> - </row> - <row> - <entry>NTSC SVCD</entry> - <entry>480x480</entry> - <entry>MPEG-2</entry> - <entry>2600 kbps</entry> - <entry>44100 Hz</entry> - <entry>MP2</entry> - <entry>384 kbps (max)</entry> - <entry>30000/1001</entry> - <entry>4:3</entry> - </row> - <row> - <entry>NTSC VCD</entry> - <entry>352x240</entry> - <entry>MPEG-1</entry> - <entry>1150 kbps</entry> - <entry>44100 Hz</entry> - <entry>MP2</entry> - <entry>224 kbps</entry> - <entry>24000/1001, 30000/1001</entry> - <entry>4:3</entry> - </row> - <row> - <entry>PAL DVD</entry> - <entry>720x576, 704x576, 352x576, 352x288</entry> - <entry>MPEG-2</entry> - <entry>9800 kbps</entry> - <entry>48000 Hz</entry> - <entry>MP2,AC3,PCM</entry> - <entry>1536 kbps (max)</entry> - <entry>25</entry> - <entry>4:3, 16:9 (only for 720x576)</entry> - </row> - <row> - <entry>PAL DVD</entry> - <entry>352x288<footnoteref linkend='fn-rare-resolutions'/></entry> - <entry>MPEG-1</entry> - <entry>1856 kbps</entry> - <entry>48000 Hz</entry> - <entry>MP2,AC3,PCM</entry> - <entry>1536 kbps (max)</entry> - <entry>25</entry> - <entry>4:3, 16:9</entry> - </row> - <row> - <entry>PAL SVCD</entry> - <entry>480x576</entry> - <entry>MPEG-2</entry> - <entry>2600 kbps</entry> - <entry>44100 Hz</entry> - <entry>MP2</entry> - <entry>384 kbps (max)</entry> - <entry>25</entry> - <entry>4:3</entry> - </row> - <row> - <entry>PAL VCD</entry> - <entry>352x288</entry> - <entry>MPEG-1</entry> - <entry>1152 kbps</entry> - <entry>44100 Hz</entry> - <entry>MP2</entry> - <entry>224 kbps</entry> - <entry>25</entry> - <entry>4:3</entry> - </row> +<row> + <entry>NTSC DVD</entry> + <entry>720x480, 704x480, 352x480, 352x240</entry> + <entry>MPEG-2</entry> + <entry>9800 kbps</entry> + <entry>48000 Hz</entry> + <entry>AC3,PCM</entry> + <entry>1536 kbps (max)</entry> + <entry>30000/1001, 24000/1001</entry> + <entry>4:3, 16:9 (only for 720x480)</entry> +</row> +<row> + <entry>NTSC DVD</entry> + <entry>352x240<footnote id='fn-rare-resolutions'><para> + These resolutions are rarely used for DVDs because + they are fairly low quality.</para></footnote></entry> + <entry>MPEG-1</entry> + <entry>1856 kbps</entry> + <entry>48000 Hz</entry> + <entry>AC3,PCM</entry> + <entry>1536 kbps (max)</entry> + <entry>30000/1001, 24000/1001</entry> + <entry>4:3, 16:9</entry> +</row> +<row> + <entry>NTSC SVCD</entry> + <entry>480x480</entry> + <entry>MPEG-2</entry> + <entry>2600 kbps</entry> + <entry>44100 Hz</entry> + <entry>MP2</entry> + <entry>384 kbps (max)</entry> + <entry>30000/1001</entry> + <entry>4:3</entry> +</row> +<row> + <entry>NTSC VCD</entry> + <entry>352x240</entry> + <entry>MPEG-1</entry> + <entry>1150 kbps</entry> + <entry>44100 Hz</entry> + <entry>MP2</entry> + <entry>224 kbps</entry> + <entry>24000/1001, 30000/1001</entry> + <entry>4:3</entry> +</row> +<row> + <entry>PAL DVD</entry> + <entry>720x576, 704x576, 352x576, 352x288</entry> + <entry>MPEG-2</entry> + <entry>9800 kbps</entry> + <entry>48000 Hz</entry> + <entry>MP2,AC3,PCM</entry> + <entry>1536 kbps (max)</entry> + <entry>25</entry> + <entry>4:3, 16:9 (only for 720x576)</entry> +</row> +<row> + <entry>PAL DVD</entry> + <entry>352x288<footnoteref linkend='fn-rare-resolutions'/></entry> + <entry>MPEG-1</entry> + <entry>1856 kbps</entry> + <entry>48000 Hz</entry> + <entry>MP2,AC3,PCM</entry> + <entry>1536 kbps (max)</entry> + <entry>25</entry> + <entry>4:3, 16:9</entry> +</row> +<row> + <entry>PAL SVCD</entry> + <entry>480x576</entry> + <entry>MPEG-2</entry> + <entry>2600 kbps</entry> + <entry>44100 Hz</entry> + <entry>MP2</entry> + <entry>384 kbps (max)</entry> + <entry>25</entry> + <entry>4:3</entry> +</row> +<row> + <entry>PAL VCD</entry> + <entry>352x288</entry> + <entry>MPEG-1</entry> + <entry>1152 kbps</entry> + <entry>44100 Hz</entry> + <entry>MP2</entry> + <entry>224 kbps</entry> + <entry>25</entry> + <entry>4:3</entry> +</row> </tbody> </tgroup> </informaltable> <para> - If your movie has 2.35:1 aspect (most recent action movies), you will - have to add black borders or crop the movie down to 16:9 to make a DVD - or VCD. - If you add black borders, try to align them at 16-pixel boundaries in - order to minimize the impact on encoding performance. - Thankfully DVD has sufficiently excessive bitrate that you do not have - to worry too much about encoding efficiency, but SVCD and VCD are - highly bitrate-starved and require effort to obtain acceptable quality. +If your movie has 2.35:1 aspect (most recent action movies), you will +have to add black borders or crop the movie down to 16:9 to make a DVD or VCD. +If you add black borders, try to align them at 16-pixel boundaries in +order to minimize the impact on encoding performance. +Thankfully DVD has sufficiently excessive bitrate that you do not have +to worry too much about encoding efficiency, but SVCD and VCD are +highly bitrate-starved and require effort to obtain acceptable quality. </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-constraints-gop"> <title>GOP Size Constraints</title> + <para> - DVD, VCD, and SVCD also constrain you to relatively low - GOP (Group of Pictures) sizes. - For 30 fps material the largest allowed GOP size is 18. - For 25 or 24 fps, the maximum is 15. - The GOP size is set using the <option>keyint</option> option. +DVD, VCD, and SVCD also constrain you to relatively low +GOP (Group of Pictures) sizes. +For 30 fps material the largest allowed GOP size is 18. +For 25 or 24 fps, the maximum is 15. +The GOP size is set using the <option>keyint</option> option. </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-constraints-bitrate"> <title>Bitrate Constraints</title> + <para> - VCD video is required to be CBR at 1152 kbps. - This highly limiting constraint also comes along with an extremly low vbv - buffer size of 327 kilobits. - SVCD allows varying video bitrates up to 2500 kbps, and a somewhat less - restrictive vbv buffer size of 917 kilobits is allowed. - DVD video bitrates may range anywhere up to 9800 kbps (though typical - bitrates are about half that), and the vbv buffer size is 1835 kilobits. +VCD video is required to be CBR at 1152 kbps. +This highly limiting constraint also comes along with an extremly low vbv +buffer size of 327 kilobits. +SVCD allows varying video bitrates up to 2500 kbps, and a somewhat less +restrictive vbv buffer size of 917 kilobits is allowed. +DVD video bitrates may range anywhere up to 9800 kbps (though typical +bitrates are about half that), and the vbv buffer size is 1835 kilobits. </para> </sect3> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-vcd-dvd-output"> <title>Output Options</title> + <para> - <application>MEncoder</application> has options to control the output - format. - Using these options we can instruct it to create the correct type of - file. +<application>MEncoder</application> has options to control the output +format. +Using these options we can instruct it to create the correct type of +file. </para> <para> - The options for VCD and SVCD are called xvcd and xsvcd, because they - are extended formats. - They are not strictly compliant, mainly because the output does not - contain scan offsets. - If you need to generate an SVCD image, you should pass the output file - to - <ulink url="http://www.gnu.org/software/vcdimager/vcdimager.html">vcdimager</ulink>. +The options for VCD and SVCD are called xvcd and xsvcd, because they +are extended formats. +They are not strictly compliant, mainly because the output does not +contain scan offsets. +If you need to generate an SVCD image, you should pass the output file to +<ulink url="http://www.gnu.org/software/vcdimager/vcdimager.html">vcdimager</ulink>. </para> <para> - VCD: - <screen> - -of mpeg -mpegopts format=xvcd - </screen> +VCD: +<screen>-of mpeg -mpegopts format=xvcd</screen> </para> <para> - SVCD: - <screen> - -of mpeg -mpegopts format=xsvcd - </screen> +SVCD: +<screen>-of mpeg -mpegopts format=xsvcd</screen> </para> <para> - DVD (with timestamps on every frame, if possible): - <screen> - -of mpeg -mpegopts format=dvd:tsaf - </screen> +DVD (with timestamps on every frame, if possible): +<screen>-of mpeg -mpegopts format=dvd:tsaf</screen> </para> <para> - DVD with NTSC Pullup: - <screen> - -of mpeg -mpegopts format=dvd:tsaf:telecine -ofps 24000/1001 - </screen> - This allows 24000/1001 fps progressive content to be encoded at 30000/1001 - fps whilst maintaing DVD-compliance. +DVD with NTSC Pullup: +<screen>-of mpeg -mpegopts format=dvd:tsaf:telecine -ofps 24000/1001</screen> +This allows 24000/1001 fps progressive content to be encoded at 30000/1001 +fps whilst maintaing DVD-compliance. </para> + <sect3 id="menc-feat-vcd-dvd-output-aspect"> <title>Aspect Ratio</title> + <para> - The aspect argument of <option>-lavcopts</option> is used to encode - the aspect ratio of the file. - During playback the aspect ratio is used to restore the video to the - correct size. +The aspect argument of <option>-lavcopts</option> is used to encode +the aspect ratio of the file. +During playback the aspect ratio is used to restore the video to the +correct size. </para> <para> - 16:9 or "Widescreen" - <screen> - -lavcopts aspect=16/9 - </screen> +16:9 or "Widescreen" +<screen>-lavcopts aspect=16/9</screen> </para> <para> - 4:3 or "Fullscreen" - <screen> - -lavcopts aspect=4/3 - </screen> +4:3 or "Fullscreen" +<screen>-lavcopts aspect=4/3</screen> </para> <para> - 2.35:1 or "Cinemascope" NTSC - <screen> - -vf scale=720:368,expand=720:480 -lavcopts aspect=16/9 - </screen> - To calculate the correct scaling size, use the expanded NTSC width of - 854/2.35 = 368 +2.35:1 or "Cinemascope" NTSC +<screen>-vf scale=720:368,expand=720:480 -lavcopts aspect=16/9</screen> +To calculate the correct scaling size, use the expanded NTSC width of +854/2.35 = 368 </para> <para> - 2.35:1 or "Cinemascope" PAL - <screen> - -vf scale="720:432,expand=720:576 -lavcopts aspect=16/9 - </screen> - To calculate the correct scaling size, use the expanded PAL width of - 1024/2.35 = 432 +2.35:1 or "Cinemascope" PAL +<screen>-vf scale="720:432,expand=720:576 -lavcopts aspect=16/9</screen> +To calculate the correct scaling size, use the expanded PAL width of +1024/2.35 = 432 </para> - </sect3> + <sect3 id="menc-feat-vcd-dvd-a-v-sync"> <title>Maintaining A/V sync</title> + <para> - In order to maintain audio/video synchronization throughout the encode, - <application>MEncoder</application> has to drop or duplicate frames. - This works rather well when muxing into an AVI file, but is almost - guaranteed to fail to maintain A/V sync with other muxers such as MPEG. - This is why it is necessary to append the - <option>harddup</option> video filter at the end of the filter chain - to avoid this kind of problem. - You can find more technical information about <option>harddup</option> - in the section - <link linkend="menc-feat-dvd-mpeg4-muxing-filter-issues">Improving muxing and A/V sync reliability</link> - or in the manual page. +In order to maintain audio/video synchronization throughout the encode, +<application>MEncoder</application> has to drop or duplicate frames. +This works rather well when muxing into an AVI file, but is almost +guaranteed to fail to maintain A/V sync with other muxers such as MPEG. +This is why it is necessary to append the +<option>harddup</option> video filter at the end of the filter chain +to avoid this kind of problem. +You can find more technical information about <option>harddup</option> +in the section +<link linkend="menc-feat-dvd-mpeg4-muxing-filter-issues">Improving muxing and A/V sync reliability</link> +or in the manual page. </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-output-srate"> <title>Sample Rate Conversion</title> + <para> - If the audio sample rate in the original file is not the same as - required by the target format, sample rate conversion is required. - This is achieved using the <option>-srate</option> option and - the <option>-af lavcresample</option> audio filter together. - </para> - <para> - DVD: - <screen> - -srate 48000 -af lavcresample=48000 - </screen> +If the audio sample rate in the original file is not the same as +required by the target format, sample rate conversion is required. +This is achieved using the <option>-srate</option> option and +the <option>-af lavcresample</option> audio filter together. </para> + <para> - VCD and SVCD: - <screen> - -srate 44100 -af lavcresample=44100 - </screen> - </para> +DVD: +<screen>-srate 48000 -af lavcresample=48000</screen> +</para> + +<para> +VCD and SVCD: +<screen>-srate 44100 -af lavcresample=44100</screen> +</para> </sect3> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-vcd-dvd-lavc"> <title>Using libavcodec for VCD/SVCD/DVD Encoding</title> <sect3 id="menc-feat-vcd-dvd-lavc-intro"> <title>Introduction</title> + <para> - <systemitem class="library">libavcodec</systemitem> can be used to - create VCD/SVCD/DVD compliant video by using the appropriate options. +<systemitem class="library">libavcodec</systemitem> can be used to +create VCD/SVCD/DVD compliant video by using the appropriate options. </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-lavc-options"> <title>lavcopts</title> + <para> - This is a list of fields in <option>-lavcopts</option> that you may - be required to change in order to make a complaint movie for VCD, SVCD, - or DVD: +This is a list of fields in <option>-lavcopts</option> that you may +be required to change in order to make a complaint movie for VCD, SVCD, +or DVD: </para> <itemizedlist> @@ -4466,14 +4595,12 @@ An example with VP3 compression: Note that MP3 audio is not compliant for any of these formats, but players often have no problem playing it anyway. </para></listitem> - <listitem><para> <emphasis role="bold">abitrate</emphasis>: 224 for VCD; up to 384 for SVCD; up to 1536 for DVD, but commonly used values range from 192 kbps for stereo to 384 kbps for 5.1 channel sound. </para></listitem> - <listitem><para> <emphasis role="bold">vcodec</emphasis>: <option>mpeg1video</option> for VCD; @@ -4481,7 +4608,6 @@ An example with VP3 compression: <option>mpeg2video</option> is usually used for DVD but you may also use <option>mpeg1video</option> for CIF resolutions. </para></listitem> - <listitem><para> <emphasis role="bold">keyint</emphasis>: Used to set the GOP size. @@ -4491,24 +4617,20 @@ An example with VP3 compression: with most players. A <option>keyint</option> of 25 should never cause any problems. </para></listitem> - <listitem><para> <emphasis role="bold">vrc_buf_size</emphasis>: 327 for VCD, 917 for SVCD, and 1835 for DVD. </para></listitem> - <listitem><para> <emphasis role="bold">vrc_minrate</emphasis>: 1152, for VCD. May be left alone for SVCD and DVD. </para></listitem> - <listitem><para> <emphasis role="bold">vrc_maxrate</emphasis>: 1152 for VCD; 2500 for SVCD; 9800 for DVD. For SVCD and DVD, you might wish to use lower values depending on your own personal preferences and requirements. </para></listitem> - <listitem><para> <emphasis role="bold">vbitrate</emphasis>: 1152 for VCD; @@ -4526,241 +4648,259 @@ An example with VP3 compression: </itemizedlist> </sect3> + <sect3 id="menc-feat-vcd-dvd-lavc-examples"> <title>Examples</title> + <para> - This is a typical minimum set of <option>-lavcopts</option> for - encoding video: +This is a typical minimum set of <option>-lavcopts</option> for +encoding video: </para> <para> - VCD: - <screen> - -lavcopts vcodec=mpeg1video:vrc_buf_size=327:vrc_minrate=1152:\ - vrc_maxrate=1152:vbitrate=1152:keyint=15:acodec=mp2 - </screen> +VCD: +<screen> +-lavcopts vcodec=mpeg1video:vrc_buf_size=327:vrc_minrate=1152:\ +vrc_maxrate=1152:vbitrate=1152:keyint=15:acodec=mp2 +</screen> </para> <para> - SVCD: - <screen> - -lavcopts vcodec=mpeg2video:vrc_buf_size=917:vrc_maxrate=2500:vbitrate=1800:\ - keyint=15:acodec=mp2 - </screen> +SVCD: +<screen> +-lavcopts vcodec=mpeg2video:vrc_buf_size=917:vrc_maxrate=2500:vbitrate=1800:\ +keyint=15:acodec=mp2 +</screen> </para> <para> - DVD: - <screen> - -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ - keyint=15:acodec=ac3 - </screen> +DVD: +<screen> +-lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ +keyint=15:acodec=ac3 +</screen> </para> - </sect3> + <sect3 id="menc-feat-vcd-dvd-lavc-advanced"> <title>Advanced Options</title> + <para> - For higher quality encoding, you may also wish to add quality-enhancing - options to lavcopts, such as <option>trell</option>, - <option>mbd=2</option>, and others. - Note that <option>qpel</option> and <option>v4mv</option>, while often - useful with MPEG-4, are not usable with MPEG-1 or MPEG-2. - Also, if you are trying to make a very high quality DVD encode, it may - be useful to add <option>dc=10</option> to lavcopts. - Doing so may help reduce the appearance of blocks in flat-colored areas. - Putting it all together, this is an example of a set of lavcopts for a - higher quality DVD: +For higher quality encoding, you may also wish to add quality-enhancing +options to lavcopts, such as <option>trell</option>, +<option>mbd=2</option>, and others. +Note that <option>qpel</option> and <option>v4mv</option>, while often +useful with MPEG-4, are not usable with MPEG-1 or MPEG-2. +Also, if you are trying to make a very high quality DVD encode, it may +be useful to add <option>dc=10</option> to lavcopts. +Doing so may help reduce the appearance of blocks in flat-colored areas. +Putting it all together, this is an example of a set of lavcopts for a +higher quality DVD: </para> <para> - <screen> - -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=8000:\ - keyint=15:trell:mbd=2:precmp=2:subcmp=2:cmp=2:dia=-10:predia=-10:cbp:mv0:\ - vqmin=1:lmin=1:dc=10 - </screen> +<screen> +-lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=8000:\ +keyint=15:trell:mbd=2:precmp=2:subcmp=2:cmp=2:dia=-10:predia=-10:cbp:mv0:\ +vqmin=1:lmin=1:dc=10 +</screen> </para> - </sect3> </sect2> +<!-- ********** --> + <sect2 id="menc-feat-vcd-dvd-audio"> <title>Encoding Audio</title> + <para> - VCD and SVCD support MPEG-1 layer II audio, using one of - <systemitem class="library">toolame</systemitem>, - <systemitem class="library">twolame</systemitem>, - or <systemitem class="library">libavcodec</systemitem>'s MP2 encoder. - The libavcodec MP2 is far from being as good as the other two libraries, - however it should always be available to use. - VCD only supports constant bitrate audio (CBR) whereas SVCD supports - variable bitrate (VBR), too. - Be careful when using VBR because some bad standalone players might not - support it too well. +VCD and SVCD support MPEG-1 layer II audio, using one of +<systemitem class="library">toolame</systemitem>, +<systemitem class="library">twolame</systemitem>, +or <systemitem class="library">libavcodec</systemitem>'s MP2 encoder. +The libavcodec MP2 is far from being as good as the other two libraries, +however it should always be available to use. +VCD only supports constant bitrate audio (CBR) whereas SVCD supports +variable bitrate (VBR), too. +Be careful when using VBR because some bad standalone players might not +support it too well. </para> <para> - For DVD audio, <systemitem class="library">libavcodec</systemitem>'s - AC3 codec is used. +For DVD audio, <systemitem class="library">libavcodec</systemitem>'s +AC3 codec is used. </para> + <sect3 id="menc-feat-vcd-dvd-audio-toolame"> <title>toolame</title> + <para> - For VCD and SVCD: - <screen> - -oac toolame -toolameopts br=224 - </screen> +For VCD and SVCD: +<screen>-oac toolame -toolameopts br=224</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-audio-twolame"> <title>twolame</title> + <para> - For VCD and SVCD: - <screen> - -oac twolame -twolameopts br=224 - </screen> +For VCD and SVCD: +<screen>-oac twolame -twolameopts br=224</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-audio-lavc"> <title>libavcodec</title> + <para> - For DVD with 2 channel sound: - <screen> - -oac lavc -lavcopts acodec=ac3:abitrate=192 - </screen> +For DVD with 2 channel sound: +<screen>-oac lavc -lavcopts acodec=ac3:abitrate=192</screen> </para> + <para> - For DVD with 5.1 channel sound: - <screen> - -channels 6 -oac lavc -lavcopts acodec=ac3:abitrate=384 - </screen> +For DVD with 5.1 channel sound: +<screen>-channels 6 -oac lavc -lavcopts acodec=ac3:abitrate=384</screen> </para> + <para> - For VCD and SVCD: - <screen> - -oac lavc -lavcopts acodec=mp2:abitrate=224 - </screen> +For VCD and SVCD: +<screen>-oac lavc -lavcopts acodec=mp2:abitrate=224</screen> </para> </sect3> - </sect2> +<!-- ********** --> + <sect2 id="menc-feat-vcd-dvd-all"> <title>Putting it all Together</title> + <para> - This section shows some complete commands for creating VCD/SVCD/DVD - compliant videos. +This section shows some complete commands for creating VCD/SVCD/DVD +compliant videos. </para> + <sect3 id="menc-feat-vcd-dvd-all-pal-dvd"> <title>PAL DVD</title> + <para> - <screen> - mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf -vf scale=720:576,\ - harddup -srate 48000 -af lavcresample=48000 -lavcopts vcodec=mpeg2video:\ - vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:keyint=15:acodec=ac3:\ - abitrate=192:aspect=16/9 -ofps 25 \ +<screen> +mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf \ + -vf scale=720:576,harddup -srate 48000 -af lavcresample=48000 \ + -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ +keyint=15:acodec=ac3:abitrate=192:aspect=16/9 -ofps 25 \ -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-ntsc-dvd"> <title>NTSC DVD</title> + <para> - <screen> - mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf -vf scale=720:480,\ - harddup -srate 48000 -af lavcresample=48000 -lavcopts vcodec=mpeg2video:\ - vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:keyint=18:acodec=ac3:\ - abitrate=192:aspect=16/9 -ofps 30000/1001 \ +<screen> +mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=dvd:tsaf \ + -vf scale=720:480,harddup -srate 48000 -af lavcresample=48000 \ + -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ +keyint=18:acodec=ac3:abitrate=192:aspect=16/9 -ofps 30000/1001 \ -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-pal-ac3-copy"> <title>PAL AVI Containing AC3 Audio to DVD</title> + <para> - If the source already has AC3 audio, use -oac copy instead of re-encoding it. - <screen> - mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd:tsaf -vf scale=720:576,\ - harddup -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:\ - vbitrate=5000:keyint=15:aspect=16/9 -ofps 25 \ - -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +If the source already has AC3 audio, use -oac copy instead of re-encoding it. +<screen> +mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd:tsaf \ + -vf scale=720:576,harddup -ofps 25 \ + -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ +keyint=15:aspect=16/9 -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> +</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-ntsc-ac3-copy"> <title>NTSC AVI Containing AC3 Audio to DVD</title> + <para> - If the source already has AC3 audio, and is NTSC @ 24000/1001 fps: - <screen> - mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd:tsaf:telecine \ +If the source already has AC3 audio, and is NTSC @ 24000/1001 fps: +<screen> +mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd:tsaf:telecine \ -vf scale=720:480,harddup -lavcopts vcodec=mpeg2video:vrc_buf_size=1835:\ vrc_maxrate=9800:vbitrate=5000:keyint=15:aspect=16/9 -ofps 24000/1001 \ -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-pal-svcd"> <title>PAL SVCD</title> + <para> - <screen> - mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xsvcd -vf \ - scale=480:576,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ - vcodec=mpeg2video:mbd=2:keyint=15:vrc_buf_size=917:vrc_minrate=600:\ - vbitrate=2500:vrc_maxrate=2500:acodec=mp2:abitrate=224 -ofps 25 \ - -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> +<screen> +mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xsvcd -vf \ + scale=480:576,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ + vcodec=mpeg2video:mbd=2:keyint=15:vrc_buf_size=917:vrc_minrate=600:\ +vbitrate=2500:vrc_maxrate=2500:acodec=mp2:abitrate=224 -ofps 25 \ + -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> </screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-ntsc-svcd"> <title>NTSC SVCD</title> + <para> - <screen> - mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xsvcd -vf \ - scale=480:480,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ - vcodec=mpeg2video:mbd=2:keyint=18:vrc_buf_size=917:vrc_minrate=600:\ - vbitrate=2500:vrc_maxrate=2500:acodec=mp2:abitrate=224 -ofps 30000/1001 \ - -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +<screen> +mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xsvcd -vf \ + scale=480:480,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ + vcodec=mpeg2video:mbd=2:keyint=18:vrc_buf_size=917:vrc_minrate=600:\ +vbitrate=2500:vrc_maxrate=2500:acodec=mp2:abitrate=224 -ofps 30000/1001 \ + -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> +</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-pal-vcd"> <title>PAL VCD</title> + <para> - <screen> - mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xvcd -vf \ - scale=352:288,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ - vcodec=mpeg1video:keyint=15:vrc_buf_size=327:vrc_minrate=1152:vbitrate=1152:\ - vrc_maxrate=1152:acodec=mp2:abitrate=224 -ofps 25 \ - -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +<screen> +mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xvcd -vf \ + scale=352:288,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ + vcodec=mpeg1video:keyint=15:vrc_buf_size=327:vrc_minrate=1152:\ +vbitrate=1152:vrc_maxrate=1152:acodec=mp2:abitrate=224 -ofps 25 \ + -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> +</screen> </para> </sect3> + <sect3 id="menc-feat-vcd-dvd-all-ntsc-vcd"> <title>NTSC VCD</title> + <para> - <screen> - mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xvcd -vf \ - scale=352:240,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ - vcodec=mpeg1video:keyint=18:vrc_buf_size=327:vrc_minrate=1152:vbitrate=1152:\ - vrc_maxrate=1152:acodec=mp2:abitrate=224 -ofps 30000/1001 \ - -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> - </screen> +<screen> +mencoder -oac lavc -ovc lavc -of mpeg -mpegopts format=xvcd -vf \ + scale=352:240,harddup -srate 44100 -af lavcresample=44100 -lavcopts \ + vcodec=mpeg1video:keyint=18:vrc_buf_size=327:vrc_minrate=1152:\ +vbitrate=1152:vrc_maxrate=1152:acodec=mp2:abitrate=224 -ofps 30000/1001 \ + -o <replaceable>movie.mpg</replaceable> <replaceable>movie.avi</replaceable> +</screen> </para> </sect3> - </sect2> - </sect1> - </chapter> |