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author | 2004-01-02 23:07:07 +0000 | |
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committer | 2004-01-02 23:07:07 +0000 | |
commit | fad08c508f1d7d2802dd1518b122fadeca3b724a (patch) | |
tree | b18e7184525e34e418dd41f6e3ca77bdf4162518 | |
parent | 3a3d052d8a1ebd3160f3fc24e8cc4126947ee78f (diff) |
DVD ripping section added courtesy of Samuli Kärkkäinen with some
improvements made by me.
git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@11733 b3059339-0415-0410-9bf9-f77b7e298cf2
-rw-r--r-- | DOCS/xml/en/mencoder.xml | 183 |
1 files changed, 181 insertions, 2 deletions
diff --git a/DOCS/xml/en/mencoder.xml b/DOCS/xml/en/mencoder.xml index 64367e9872..086465560f 100644 --- a/DOCS/xml/en/mencoder.xml +++ b/DOCS/xml/en/mencoder.xml @@ -62,7 +62,7 @@ once, unlike in 2-pass mode. The schematics: <emphasis>First pass:</emphasis> <screen>mencoder <replaceable>file/DVD</replaceable> -ovc frameno -oac mp3lame -lameopts vbr=3 -o frameno.avi</screen> - + An audio-only avi file will be created, containing <emphasis role="bold">only</emphasis> the requested audio stream. Don't forget <option>-lameopts</option>, if you need to set it. If you were encoding a @@ -515,7 +515,7 @@ are reported as working. </para> <para> -A typical usage of this feature is to set the matrices preferred by the +A typical usage of this feature is to set the matrices preferred by the <ulink url="http://www.kvcd.net/">KVCD</ulink> specifications. </para> @@ -569,4 +569,183 @@ vcodec=mpeg2video:intra_matrix=8,9,12,22,26,27,29,34,9,10,14,26,27,29,34,37, </para> </sect1> +<sect1 id="menc-feat-dvd-mpeg4"> +<title>Making a high quality MPEG4 ("DivX") rip of a DVD movie</title> + +<para> + Ripping a DVD title into a maximally high quality MPEG4 (DivX) file + involves many considerations. Below is an example of the process when + there is no file size goal (other than perhaps fitting the result into 2GB). + <systemitem class="library">libavcodec</systemitem> will be used for the video, + and the audio will be copied as is without any changes. +</para> + +<sect2 id="menc-feat-dvd-mpeg4-crop"> +<title>Cropping</title> +<para> + Play the DVD and run the crop detection filter + (<option>-vf cropdetect</option>) on it. This gives you a crop rectangle + to use for encoding. The reason for cropping is that many movies are + not shot in a standard DVD aspect ratio (16/9 or 4/3), or, for whatever + reason, the picture does not properly fill the frame. So you want to crop + out the pointless black bars when you rip. It also improves the quality + of the rip since the sharp edge of the black bars wastes a lot of bits. + A common aspect is 2.35, which is cinescope. Most big blockbuster + movies have this aspect ratio. +</para> +</sect2> + +<sect2 id="menc-feat-dvd-mpeg4-quality"> +<title>Quality level</title> +<para> + Next you need to choose the desired quality level. When there is no + need to fit the resulting file on CDs or the like, using constant + quantizing AKA constant quality is a good choice. That way each frame + is given as much bits as its needs to keep the quality at the desired + level, but multiple encoding passes are not needed. With + <systemitem class="library">libavcodec</systemitem>, you get constant + quality by using + <option>-lavcopts vqscale=<replaceable>N</replaceable></option>. + <option>vqscale=3</option> should give you a file below 2GB in size, + depending mainly on the movie length and video noisiness (the more + noise, the harder it is to compress.) +</para></sect2> + +<sect2 id="menc-feat-dvd-mpeg4-2gb"> +<title>Files over 2GB</title> +<para> + If the file resulting from constant quality encoding is over 2GB big, + you will have to create an index to be able to view it properly. + Either + +<itemizedlist> +<listitem><para> + play the file with <option>-forceidx</option> to create an index + on the fly or + </para></listitem> +<listitem><para> + use <option>-saveidx</option> to write an index to a file once and + <option>-loadidx</option> to use it when playing the file. + </para></listitem> +</itemizedlist> + + If this bothers you, you may want to keep the file size below 2GB. +</para> + +<para> + There are two ways to avoid this. You can try encoding again using + <option>vqscale=4</option> and see if both the resulting file size + and picture quality are acceptable. You can also use + <link linkend="menc-feat-divx4">2 pass encoding</link>. + As you will be copying the audio track as is and hence know its + bitrate, and you know the running time of the movie, you can + compute the required bitrate to give to the + <option>-lavcopts vbitrate=<replaceable>bitrate</replaceable></option> + option without using + <link linkend="menc-feat-divx4">3 pass encoding</link>. +</para></sect2> + +<sect2 id="menc-feat-dvd-mpeg4-deinterlacing"> +<title>Deinterlacing</title> +<para> + If the movie is interlaced, you may want to deinterlace it as part of + the ripping. It is debatable whether deinterlacing should be done at + this stage. The benefit is that deinterlacing when converting to + MPEG4 makes compression better, and viewing easier and less CPU + intensive on computer monitors as no deinterlacing is required at + that stage. +</para> + +<para> + If deinterlacing at the ripping stage is a good idea depends on + the DVD. If the DVD is made from film, which was shot at 24 fps, you + can as well deinterlace while ripping. If, however, the original was + 50/60 fps video, converting into deinterlaced 23.976/25 fps video + will lose information. If you do decide to interlace, you can further + experiment with different deinterlacing filters. See + <ulink url="http://www.wieser-web.de/MPlayer/">http://www.wieser-web.de/MPlayer/</ulink> + for examples. A good starting point is <option>-vf pp=fd</option>. +</para> + +<para> + If you are both cropping and deinterlacing, deinterlace + <emphasis>before</emphasis> cropping. Actually, this is not necessary + if the crop offset is vertically a multiple of 2 pixels. However with + some other filters like dering you should always crop last, so it's a + good habit to put the crop filter last. +</para></sect2> + +<sect2 id="menc-feat-dvd-mpeg4-telecine"> +<title>Inverse telecine</title> +<para> + If you are ripping a PAL DVD, which is 25 fps, you do not need to + think about the fps. Just use 25 fps. NTSC DVDs on the other hand are + 29.97 fps (often rounded to 30 fps, but that is not what they are). + If the movie was shot for TV, you again do not need to touch the fps. + But if the movie was shot on film, and hence at (exactly) 24 fps, + it has been converted to 29.97 fps when making the DVD. That + conversion where 12 fields are added to each 24 frames of film is + called telecine. For more info about telecine, see a + <ulink url="http://www.google.com/search?q=telecine+field+23.976"> + Google search for "telecine field 23.976"</ulink>. +</para> + +<para> + In case you have such a telecined DVD, you will want to do inverse + telecine, that is convert the movie to 23.976 fps (29.97*4/5). + Otherwise camera panning will look jerky and awful. You can use + <option>-ofps 23.976</option> for this. Anything that is shown in + theatres is shot on film and needs inverse telecine, TV shows do not. +</para></sect2> + +<sect2 id="menc-feat-dvd-mpeg4-scaling"> +<title>Scaling and aspect ratio</title> +<para> + For best quality, do not scale the movie while ripping. Scaling + causes artifacts and makes the file larger. Pixels in DVD movies + are not square, so DVD movies include info about the correct aspect + ratio. It is possible to store the aspect ratio in the MPEG4 header + of the output file. Most video players ignore this info, but + <application>MPlayer</application> honors it. So if you are only + going to use <application>MPlayer</application> for viewing the + ripped file, you do not need to scale the movie, just pass + <option>-lavcopts autoaspect</option> to + <application>MEncoder</application> and things will + automagically work right. If you must scale the movie, be + careful about getting the size right especially if you do cropping. +</para> +</sect2> + +<sect2 id="menc-feat-dvd-mpeg4-summary"> +<title>Summing it up</title> +<para> + With all of the above mentioned in mind, a suitable encoding command + might be + + <screen> +mencoder dvd://1 -aid 128 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vqscale=3:vhq:v4mv:trell:autoaspect \ + -ofps 23.976 -vf crop=720:364:0:56 -o Harry_Potter_2.avi + </screen> + + Here <option>dvd://1</option> gives the DVD title to rip. Option + <option>-aid 128</option> says to use audio track 128, and + <option>-oac copy</option> to copy it as is. You'll have to use + <application>MPlayer</application> to find out the right values for + these options. +</para> + +<para> + Options <option>vhq:v4mv:trell</option> for + <option>-lavcopts</option> improve quality versus bitrate, but make + encoding take longer. Especially <option>trell</option> slows + encoding down but also increases quality visibly. If you want to + deinterlace, add a <option>pp</option> filter to + <option>-vf</option>, for example + <option>-vf pp=fd,crop=720:364:0:56</option> (in that order). If you don't need + inverse telecine, leave out the <option>-ofps 23.976</option>. +</para> +</sect2> + +</sect1> + </chapter> |