path: root/DOCS/xml/en/mencoder.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision$ -->
<chapter id="mencoder">
<title>Encoding with <application>MEncoder</application></title>

<para>
For the complete list of available <application>MEncoder</application> options
and examples, please see the man page. For a series of hands-on examples and
detailed guides on using several encoding parameters, read the
<ulink url="../../tech/encoding-tips.txt">encoding-tips</ulink> that were
collected from several mailing list threads on mplayer-users. Search the
<ulink url="http://mplayerhq.hu/pipermail/mplayer-users/">archives</ulink>
for a wealth of discussions about all aspects of and problems related to
encoding with <application>MEncoder</application>.
</para>

<sect1 id="menc-feat-mpeg4">
<title>Encoding 2-pass MPEG4 (&quot;DivX&quot;)</title>

<para>
The name comes from the fact that this method encodes the file <emphasis>twice</emphasis>.
The first encoding (dubbed pass) creates some temporary files
(<filename>*.log</filename>) with a size of few megabytes, do not delete
them yet (you can delete the AVI). In the second pass, the 2-pass output
file is created, using the bitrate data from the temporary files. The
resulting file will have much better image quality. If this is the first
time you heard about this, you should consult some guides available on the
net.
</para>

<example>
<title>copy audio track</title>
<para>
2-pass encode of a DVD to an MPEG4 (&quot;DivX&quot;) AVI while copying
the audio track.
<screen>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac copy -o <replaceable>movie.avi</replaceable>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac copy -o <replaceable>movie.avi</replaceable>
</screen>
</para>
</example>

<example>
<title>encode audio track</title>
<para>
2-pass encode of a DVD to an MPEG4 (&quot;DivX&quot;) AVI while encoding
the audio track to MP3.
<screen>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=1 -oac mp3lame -lameopts vbr=3 -o <replaceable>movie.avi</replaceable>
mencoder dvd://2 -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -oac mp3lame -lameopts vbr=3 -o <replaceable>movie.avi</replaceable>
</screen>
</para>
</example>
</sect1>

<sect1 id="menc-feat-mpeg">
<title>Encoding to MPEG format</title>
<para>
<application>MEncoder</application> can create MPEG (MPEG-PS) format output
files. It's probably useful only with
<link linkend="ffmpeg"><systemitem class="library">libavcodec</systemitem></link>'s
<emphasis>mpeg1video</emphasis> codec, because players - except
<application>MPlayer</application> - expect MPEG1 video, and MPEG1 layer 2 (MP2)
audio streams in MPEG files.
</para>

<para>
This feature is not very useful right now, aside that it probably has many bugs,
but the more importantly because <application>MEncoder</application> currently
cannot encode MPEG1 layer 2 (MP2) audio, which all other players expect in MPEG files.
</para>

<para>
To change <application>MEncoder</application>'s output file format,
use the <option>-of mpeg</option> option.
</para>

<para>
Example:
<screen>
mencoder -of mpeg -ovc lavc -lavcopts vcodec=mpeg1video -oac copy <replaceable>other_options</replaceable> <replaceable>media.avi</replaceable> -o <replaceable>output.mpg</replaceable>
</screen>
</para>
</sect1>


<sect1 id="menc-feat-rescale">
<title>Rescaling movies</title>

<para>
Often the need to resize movie images' size emerges. Its reasons can be
many: decreasing file size, network bandwidth,etc. Most people even do
rescaling when converting DVDs or SVCDs to DivX AVI. If you wish to rescale,
read the <link linkend="aspect">Preserving aspect ratio</link> section.
</para>

<para>
The scaling process is handled by the <literal>scale</literal> video filter:
<option>-vf scale=<replaceable>width</replaceable>:<replaceable>height</replaceable></option>.
Its quality can be set with the <option>-sws</option> option.
If it's not specified, <application>MEncoder</application> will use 0: fast
bilinear.
</para>

<para>
Usage:
<screen>
mencoder <replaceable>input.mpg</replaceable> -ovc lavc -lavcopts vcodec=mpeg4 -vf scale=640:480 -o <replaceable>output.avi</replaceable>
</screen>
</para>
</sect1>


<sect1 id="menc-feat-streamcopy">
<title>Stream copying</title>

<para>
<application>MEncoder</application> can handle input streams in two ways:
<emphasis role="bold">encode</emphasis> or <emphasis role="bold">copy</emphasis>
them. This section is about <emphasis role="bold">copying</emphasis>.
</para>

<itemizedlist>
<listitem><para>
  <emphasis role="bold">Video stream</emphasis> (option <option>-ovc copy</option>):
  nice stuff can be done :) Like, putting (not converting!) FLI or VIVO or
  MPEG1 video into an AVI file!  Of course only
  <application>MPlayer</application> can play such files :) And it probably
  has no real life value at all. Rationally: video stream copying can be
  useful for example when only the audio stream has to be encoded (like,
  uncompressed PCM to MP3).
  </para></listitem>
<listitem><para>
  <emphasis role="bold">Audio stream</emphasis> (option <option>-oac copy</option>):
  straightforward.  It is possible to take an external audio file (MP3,
  WAV) and mux it into the output stream. Use the
  <option>-audiofile <replaceable>filename</replaceable></option> option
  for this.
  </para></listitem>
</itemizedlist>
</sect1>


<sect1 id="menc-feat-fix-avi">
<title>Fixing AVIs with broken index or interleaving</title>

<para>
Easiest thing. We simply copy the video and audio streams, and
<application>MEncoder</application> generates the index. Of course this cannot fix possible bugs in
the video and/or audio streams. It also fixes files with broken interleaving,
thus the <option>-ni</option> option won't be needed for them anymore.
</para>

<para>
Command:
<screen>
mencoder -idx <replaceable>input.avi</replaceable> -ovc copy -oac copy -o <replaceable>output.avi</replaceable><!--
--></screen>
</para>


<sect2 id="menc-feat-appending">
<title>Appending multiple AVI files</title>

<para>
As a side-effect, the broken AVI fixer function enables <application>MEncoder</application>
to append 2 (or more) AVI files:
</para>

<para>
Command:
<screen>cat <replaceable>1.avi</replaceable> <replaceable>2.avi</replaceable> &gt; <replaceable>3.avi</replaceable>
mencoder -noidx -ovc copy -oac copy -o <replaceable>output.avi</replaceable> <replaceable>3.avi</replaceable></screen>
</para>

<note><para>
This expects <filename>1.avi</filename> and <filename>2.avi</filename> to use
the same codecs, resolution, stream rate etc, and at least <filename>1.avi</filename>
must not be broken. You may need to fix your input AVI files first, as described
<link linkend="menc-feat-fix-avi">above</link>.
</para></note>
</sect2>
</sect1>

<sect1 id="menc-feat-enc-libavcodec">
<title>Encoding with the <systemitem class="library">libavcodec</systemitem>
  codec family</title>

<para>
<link linkend="ffmpeg"><systemitem class="library">libavcodec</systemitem></link>
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):

<informaltable frame="all">
<tgroup cols="2">
<thead>
<row><entry>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>h263</entry><entry>
  H263
  </entry></row>
<row><entry>h263p</entry><entry>
  H263 Plus
  </entry></row>
<row><entry>mpeg4</entry><entry>
  ISO standard MPEG4 (DivX 5, XVID compatible)
  </entry></row>
<row><entry>msmpeg4</entry><entry>
  pre-standard MPEG4 variant by MS, v3 (aka DivX3)
  </entry></row>
<row><entry>msmpeg4v2</entry><entry>
  pre-standard MPEG4 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>
  an old RealVideo codec
  </entry></row>
<row><entry>mpeg1video</entry><entry>
  MPEG1 video
  </entry></row>
<row><entry>mpeg2video</entry><entry>
  MPEG2 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>
</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>
</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>
</sect1>


<sect1 id="menc-feat-enc-images">
<title>Encoding from multiple input image files (JPEG, PNG, TGA, SGI)</title>

<para>
<application>MEncoder</application> is capable of creating movies from one
or more JPEG, PNG or TGA files.  With simple framecopy it can create MJPEG
(Motion JPEG), MPNG (Motion PNG) or MTGA (Motion TGA) files.
</para>

<orderedlist>
<title>Explanation of the process:</title>
<listitem><para>
  <application>MEncoder</application> <emphasis>decodes</emphasis> the input image(s) with
  <systemitem class="library">libjpeg</systemitem> (when decoding PNGs, it
  will use <systemitem class="library">libpng</systemitem>).
  </para></listitem>
<listitem><para>
  <application>MEncoder</application> then feeds the decoded image to the
  chosen video compressor (DivX4, XviD, FFmpeg msmpeg4, etc.).
  </para></listitem>
</orderedlist>

<formalpara>
<title>Examples</title>
<para>
The explanation of the <option>-mf</option> option is in the man page.

<informalexample>
<para>
Creating an MPEG4 file from all the JPEG files in the current directory:
<screen>
mencoder mf://*.jpg -mf type=jpg:w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o <replaceable>output.avi</replaceable>
</screen>
</para>
</informalexample>

<informalexample>
<para>
Creating an MPEG4 file from some JPEG files in the current directory:
<screen>
mencoder mf://<replaceable>frame001.jpg,frame002.jpg</replaceable> -mf type=jpg:w=800:h=600:fps=25 -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o <replaceable>output.avi</replaceable>
</screen>
</para>
</informalexample>

<informalexample>
<para>
Creating a Motion JPEG (MJPEG) file from all the JPEG files in the current
directory:
<screen>
mencoder mf://*.jpg -mf type=jpg:w=800:h=600:fps=25 -ovc copy -oac copy -o <replaceable>output.avi</replaceable>
</screen>
</para>
</informalexample>

<informalexample>
<para>
Creating an uncompressed file from all the PNG files in the current directory:
<screen>
mencoder mf:// -mf w=800:h=600:fps=25:type=png -ovc raw -oac copy -o <replaceable>output.avi</replaceable>
</screen>
</para>
</informalexample>

<note><para>
Width must be integer multiple of 4, it's a limitation of the RAW RGB AVI format.
</para></note>

<informalexample>
<para>
Creating a Motion PNG (MPNG) file from all the PNG files in the current
directory:
<screen>
mencoder mf://*.jpg -mf w=800:h=600:fps=25:type=png -ovc copy -oac copy -o <replaceable>output.avi</replaceable> <!--
--></screen>
</para>
</informalexample>

<informalexample>
<para>
Creating a Motion TGA (MTGA) file from all the TGA files in the current
directory:
<screen>
mencoder mf://*.tga -mf w=800:h=600:fps=25:type=tga -ovc copy -oac copy -o <replaceable>output.avi</replaceable><!--
--></screen>
</para>
</informalexample>

</para>
</formalpara>
</sect1>


<sect1 id="menc-feat-extractsub">
<title>Extracting DVD subtitles to VOBsub file</title>

<para>
<application>MEncoder</application> is capable of extracting subtitles from
a DVD into VOBsub formatted files. They consist of a pair of files ending in
<filename>.idx</filename> and <filename>.sub</filename> and are usually
packaged in a single <filename>.rar</filename> archive.
<application>MPlayer</application> can play these with the
<option>-vobsub</option> and <option>-vobsubid</option> options.
</para>

<para>
You specify the basename (i.e without the <filename>.idx</filename> or
<filename>.sub</filename> extension) of the output files with
<option>-vobsubout</option> and the index for this subtitle in the
resulting files with <option>-vobsuboutindex</option>.
</para>

<para>
If the input is not from a DVD you should use <option>-ifo</option> to
indicate the <filename>.ifo</filename> file needed to construct the
resulting <filename>.idx</filename> file.
</para>

<para>
If the input is not from a DVD and you do not have the
<filename>.ifo</filename> file you will need to use the
<option>-vobsubid</option> option to let it know what language id to put in
the <filename>.idx</filename> file.
</para>

<para>
Each run will append the running subtitle if the <filename>.idx</filename>
and <filename>.sub</filename> files already exist. So you should remove any
before starting.
</para>

<example>
<title>Copying two subtitles from a DVD while doing 3-pass encoding</title>
<screen>
rm subtitles.idx subtitles.sub
mencoder dvd://1 -vobsubout subtitles -vobsuboutindex 0 -sid 2 -o frameno.avi -ovc frameno
mencoder dvd://1 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=1
mencoder dvd://1 -oac copy -ovc lavc -lavcopts vcodec=mpeg4:vpass=2 -vobsubout subtitles -vobsuboutindex 1 -sid 5<!--
--></screen>
</example>

<example>
<title>Copying a french subtitle from an MPEG file</title>
<screen>
rm subtitles.idx subtitles.sub
mencoder <replaceable>movie.mpg</replaceable> -ifo <replaceable>movie.ifo</replaceable> -vobsubout subtitles -vobsuboutindex 0 -vobsuboutid fr -sid 1<!--
--></screen>
</example>

</sect1>

<sect1 id="aspect">
<title>Preserving aspect ratio</title>
<para>
DVDs and SVCDs (i.e. MPEG1/2) files contain an aspect ratio value, which
describes how the player should scale the video stream, so humans won't
have egg heads (ex.: 480x480 + 4:3 = 640x480). However when encoding to AVI
(DivX) files, you have be aware that AVI headers don't store this value.
Rescaling the movie is disgusting and time consuming, there has to be a better
way!
</para>

<para>There is</para>

<para>
MPEG4 has an unique feature: the video stream can contain its needed aspect
ratio. Yes, just like MPEG1/2 (DVD, SVCD) and H263 files. Regretfully, there are
<emphasis role="bold">no</emphasis> video players outside which support this
attribute of MPEG4, except <application>MPlayer</application>.
</para>

<para>
This feature can be used only with
<link linkend="ffmpeg"><systemitem class="library">libavcodec</systemitem></link>'s
<systemitem>mpeg4</systemitem> codec. Keep in mind: although
<application>MPlayer</application> will correctly play the created file,
other players will use the wrong aspect ratio.
</para>

<para>
You seriously should crop the black bands over and below the movie image.
See the man page for the usage of the <systemitem>cropdetect</systemitem> and
<systemitem>crop</systemitem> filters.
</para>

<para>
Usage
<screen>mencoder <replaceable>sample-svcd.mpg</replaceable> -ovc lavc -lavcopts vcodec=mpeg4:autoaspect -vf crop=714:548:0:14 -oac copy -o <replaceable>output.avi</replaceable></screen>
</para>
</sect1>

<sect1 id="custommatrices"><title>Custom inter/intra matrices</title>

<para>
With this feature of
<link linkend="ffmpeg"><systemitem class="library">libavcodec</systemitem></link>
you are able to set custom inter (I-frames/key frames) and intra
(P-frames/predicted frames) matrices. It is supported by many of the codecs:
<systemitem>mpeg1video</systemitem> and <systemitem>mpeg2video</systemitem>
are reported as working.
</para>

<para>
A typical usage of this feature is to set the matrices preferred by the
<ulink url="http://www.kvcd.net/">KVCD</ulink> specifications.
</para>

<para>
The <emphasis role="bold">KVCD &quot;Notch&quot; Quantization Matrix:</emphasis>
</para>

<para>
Intra:
<screen>
 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
</screen>

Inter:
<screen>
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
</screen>
</para>

<para>
Usage:
<screen>
$ 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,
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>
</sect1>

<sect1 id="menc-feat-dvd-mpeg4">
<title>Making a high quality MPEG4 (&quot;DivX&quot;) 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 three 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-mpeg4">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 video bitrate to give to the
  <option>-lavcopts vbitrate=<replaceable>bitrate</replaceable></option>
  option without using
  <link linkend="menc-feat-mpeg4">3 pass encoding</link>.
</para>

<para>
  The third and possibly the best option may be to slightly scale down
  the resolution. The uniform slight softening and loss of detail is
  visually more appealing than the blockiness and other artifacts
  caused by MPEG compression. Scaling down also effectively reduces the
  noise of the picture, which is good, as noise is hard to compress.
</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 deinterlace, 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 &quot;telecine field 23.976&quot;</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 down
  obviously loses detail, and scaling up causes artifacts and obviously
  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>

<sect1 id="menc-feat-telecine">
<title>How to deal with telecine and interlacing within NTSC DVDs</title>

<formalpara>
<title>Introduction</title>
<para>
  I suggest you visit this page if you don't understand much of what
  is written in this document:
  <ulink url="http://www.divx.com/support/guides/guide.php?gid=10">http://www.divx.com/support/guides/guide.php?gid=10</ulink>
  This URL links to an understandable and reasonably comprehensive
  description of what telecine is.
</para></formalpara>

<para>
  For technical reasons pertaining to the limitations of early
  television hardware, all video intended to be displayed on an NTSC
  television set must be 59.94 fields per second. Made-for-TV movies
  and shows are often filmed directly at 59.94 fields per second, but
  the majority of cinema is filmed at 24 or 23.976 frames per
  second. When cinematic movie DVDs are mastered, the video is then
  converted for television using a process called telecine.
</para>

<para>
  On a DVD, the video is never actually stored as 59.94 fields per
  second. For video that was originally 59.94, each pair of fields is
  combined to form a frame, resulting in 29.97 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, 23.976 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 23.976 frames per second, it becomes 59.94 fields per
  second, and is stored on the disk as 29.97 frames per second.
</para>

<para>
  When looking at individual frames formed from 59.94 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 1/59.94th of a
  second 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>

<para>
Notes:
</para>
<itemizedlist>
<listitem><para>
  This section only applies to NTSC DVDs, and not PAL.
  </para></listitem>
<listitem><para>
  The example <application>MEncoder</application> lines throughout the
  document are <emphasis role="bold">not</emphasis> intended for
  actual use. They are simply the bare minimum required to encode the
  pertaining video category. How to make good DVD rips or fine-tune
  <systemitem class="library">libavcodec</systemitem> for maximum
  quality is not within the scope of this document.
  </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>
</itemizedlist>

<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 23.976 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: 24fps progressive NTSC content detected, switching framerate.</screen>

  From this point forward, demux_mpg should never say it finds
  &quot;30fps NTSC content.&quot;
</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 wouldn't expect. I've 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 is referred to as &quot;soft-telecine&quot;
  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 23.976, 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.
</para>

<para>
  Watching a telecined video, you will see interlacing artifacts that
  seem to &quot;blink&quot;: they repeatedly appear and disappear.
  You can look closely at this by
  <orderedlist>
  <listitem>
    <screen>mplayer dvd://1 -speed 0.1</screen>
    </listitem>
  <listitem><para>
    Seek to a part with motion.
    </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 and
    <application>MEncoder</application> cannot losslessly convert it
    to progressive. If you don't see any pattern at all, then it is
    most likely interlaced.
    </para></listitem>
  </orderedlist>
</para>

<para>
  Sometimes telecined video is referred to as &quot;hard-telecine&quot;.
</para>
</sect3>

<sect3 id="menc-feat-telecine-ident-interlaced">
<title>Interlaced</title>
<para>

  Interlaced video was originally filmed at 59.94 fields per second,
  and stored on the DVD as 29.97 frames per second. The interlacing is
  a result of combining pairs of fields into frames, because within
  each frame, each field is 1/59.94 seconds apart.
</para>

<para>
  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 with <option>-speed 0.1</option>,
  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 &quot;mixed progressive and telecine&quot; video was originally
  23.976 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 &quot;30fps
  NTSC&quot; and &quot;24fps progressive NTSC&quot;. Watch the bottom of
  <application>MPlayer</application>'s output to see these messages.
</para>

<para>
  You should check the &quot;30fps NTSC&quot; 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 &quot;mixed progressive and interlaced&quot; content, progressive
  and interlaced video have been spliced together.
</para>

<para>
  This category looks just like &quot;mixed progressive and telecine&quot;,
  until you examine the 30fps sections and see that they don't 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.
</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 23.976</option>. Otherwise, <application>MEncoder</application>
  will try to encode at 29.97 fps and duplicate frames.
</para>

<para>
  <screen>mencoder dvd://1 -nosound -ovc lavc -ofps 23.976</screen>
</para>
</sect3>

<sect3 id="menc-feat-telecine-encode-telecined">
<title>Telecined</title>
<para>
  Telecine can be reversed to retrieve the original 23.976 content,
  using a process called inverse-telecine.
  <application>MPlayer</application> contains two filters to
  accomplish this: <option>detc</option> and
  <option>ivtc</option>. You can read the manual page to see their
  differences, but for DVDs I've never had a problem with
  <option>ivtc</option>. Note that you should
  <emphasis role="bold">always</emphasis> inverse-telecine before any
  rescaling; unless you really know what you're doing,
  inverse-telecine before cropping, too
  <link linkend="menc-feat-telecine-footnotes">[1]</link>. Again,
  <option>-ofps 23.976</option> is needed, too.
</para>

<para>
  <screen>mencoder dvd://1 -nosound -vf ivtc=1 -ovc lavc -ofps 23.976</screen>
</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 &quot;guess&quot; 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
  parameters specifically for dealing with storing interlaced video a
  bit better: <option> ildct</option> and <option>ilme</option>. Also,
  using <option>mbd=2</option> is strongly recommended
  <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 -nosound -ovc lavc -lavcopts ildct:ilme:mbd=2</screen>
  </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
  and disadvantages. Consult <option>mplayer -pphelp</option> to see
  what's available (grep for &quot;deint&quot;), and search the
  <ulink url="http://www.mplayerhq.hu/homepage/design6/info.html#mailing_lists">
  MPlayer mailing lists</ulink> to find many discussions about the
  various filters. Again, the framerate is not changing, so no
  <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 -nosound -vf pp=lb -ovc lavc</screen>
  </para></listitem>
<listitem><para>
  Unfortunately, this option is buggy with
  <application>MEncoder</application>; it ought to work well with
  <application>MEncoder G2</application>, but that isn't here yet. You
  might experience crahes. Anyway, the purpose of <option> -vf
  tfields</option> is to create a full frame out of each field, which
  makes the framerate 59.94. The advantage of this approach is that no
  data is ever lost; however, since each frame comes from only one
  field, the missing lines have to be interpolated somehow. There are
  no very good methods of generating the missing data, and so the
  result will look a bit similar to when using some deinterlacing
  filters. Generating the missing lines creates other issues, as well,
  simply because the amount of data doubles. So, higher encoding
  bitrates are required to maintain quality, and more CPU power is
  used for both encoding and decoding. tfields has several different
  options for how to create the missing lines of each frame. If you
  use this method, then Reference the manual, and chose whichever
  option looks best for your material. Note that when using
  <option>tfields</option> you
   <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 -nosound -vf tfields=2 -ovc lavc -fps 59.94 -ofps 59.94</screen>
  </para></listitem>
<listitem><para>   
  If you plan on downscaling dramatically, you can excise and encode
  only one of the two fields. Of course, you'll lose half the vertical
  resolution, but if you plan on downscaling to at most 1/2 of the
  original, the loss won't matter much. The result will be a
  progressive 29.97 frames per second file. The procedure is to use
  <option>-vf field</option>, then crop
  <link linkend="menc-feat-telecine-footnotes">[1]</link> and scale
  appropriately. Remember that you'll have to adjust the scale to
  compensate for the vertical resolution being halved.
  <screen>mencoder dvd://1 -nosound -vf field=0 -ovc lavc</screen>
  </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 two filters that accomplish this
  natively, but a better solution most of the time is to use two
  filters in conjunction (read onward for more detail).
</para>

<itemizedlist>
<listitem><para>
  Currently the most reliable method to deal with this type of video
  is to, rather than inverse-telecine the telecined parts, telecine
  the non-telecined parts and then inverse-telecine the whole
  video. Sound confusing? softpulldown is a filter that goes through
  a video and makes the entire file telecined. If we follow
  softpulldown with either <option>detc</option> or
  <option>ivtc</option>, the final result will be entirely
  progressive. Cropping and scaling should be done after the
  inverse-telecine operations, and <option> -ofps 23.976</option> is
  needed.

  <screen>mencoder dvd://1 -nosound -vf softpulldown,ivtc=1 -ovc lavc -ofps 23.976</screen>
  </para>
  </listitem>
<listitem><para>
  <option>-vf pullup</option> is designed to inverse-telecine
  telecined material while leaving progressive data alone. Pullup
  doesn't really work well with the current
  <application>MEncoder</application>, though, and is really intended
  for use with <application>MEncoder G2</application> (whenever it's
  ready). It works fine without <option>-ofps</option>, but
  <option>-ofps</option> is needed to prevent choppy output. With
  <option>-ofps</option>, it sometimes fails. The problems arise from
  <application>MEncoder</application>'s behavior of dropping frames to
  maintain synchronization between the audio and video: it drops
  frames before sending them through the filter chain, rather than
  after. As a result, <option>pullup</option> is sometimes deprived
  of the data it needs.
  </para>

  <para>
  If <application>MEncoder</application> drops too many frames in a
  row, it starves <option>pullup</option>'s buffers and causes it to
  crash.
  </para>

  <para>
  Even if <application>MEncoder</application> only drops one frame,
  <option> pullup</option> still doesn't get to see it, and will end
  up operating on an incorrect sequence of frames. Even though this
  doesn't cause a crash, <option> pullup</option> won't be able to
  make correct decisions on how to reassemble progressive frames, and
  will either match fields together incorrectly or drop several fields
  to compensate.
  </para>
  </listitem>

<listitem><para>
  I haven't used <option>-vf filmdint</option> myself, but here's what
  D Richard Felker III has to say:

  <blockquote><para>It's OK, but IMO it tries to deinterlace rather
    than doing inverse telecine too often (much like settop DVD
    players &amp; progressive TVs) which gives ugly flickering and
    other artefacts. If you're going to use it, you at least need to
    spend some time tuning the options and watching the output first
    to make sure it's 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.
</para>

<itemizedlist>
<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
  you want to, but it may slightly degrade the progressive parts.
  </para>

  <para>
  This option should definitely not be used if you want to eventually
  display the video on an interlaced device (with a TV card, for
  example). If you have interlaced frames in a 23.976 frames per
  second video, they will be telecined along with the progressive
  frames. Half of the interlaced "frames" will be displayed for three
  fields' duration (3/59.94 seconds), resulting in a flicking
  &quot;jump back in time&quot; effect that looks quite bad. If you
  even attempt this, you <emphasis role="bold">must</emphasis> use a
  deinterlacing filter like <option>lb</option> or
  <option>l5</option>.
  </para>

  <para>
  It may also be a bad idea for progressive display, too. It will drop
  pairs of consecutive interlaced fields, resulting in a discontinuity
  that can be more visible than with the second method, which shows
  some progressive frames twice. 29.97 frames per second interlaced
  video is already a bit choppy because it really should be shown at
  59.94 fields per second, so the duplicate frames don't stand out as
  much.
  </para>
  
  <para>
  Either way, it's best to consider your content and how you intend to
  display it. If your video is 90% progressive and you never intend to
  show it on a TV, you should favor a progressive approach. If it's
  only half progressive, you probably want to encode it as if it's all
  interlaced.
  </para>
  </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>

</itemizedlist>
</sect3>

</sect2>

<sect2 id="menc-feat-telecine-footnotes">
<title>Footnotes</title>
<orderedlist>
<listitem><formalpara>
  <title>About cropping:</title>
  <para>
  Video data on DVDs are stored in a format called YUV 4:2:0. In YUV
  video, luma (&quot;brightness&quot;) and chroma (&quot;color&quot;)
  are stored separately. Because the human eye is somewhat less
  sensitive to color than it is to brightness, in a YUV 4:2:0 picture
  there is only one chroma pixel for every four luma pixels. In a
  progressive picture, each square of four luma pixels (two on each
  side) has one common chroma pixel. You must crop progressive YUV
  4:2:0 to even resolutions, and use even offsets. For example,
  <option>crop=716:380:2:26</option> is OK but
  <option>crop=716:380:3:26 </option> is not.
  </para>
  </formalpara>

  <para>
  When you are dealing with interlaced YUV 4:2:0, the situation is a
  bit more complicated. Instead of every four luma pixels in the
  <emphasis>frame</emphasis> sharing a chroma pixel, every four luma
  pixels in each <emphasis> field</emphasis> share a chroma
  pixel. When fields are interlaced to form a frame, each scanline is
  one pixel high. Now, instead of all four luma pixels being in a
  square, there are two pixels side-by-side, and the other two pixels
  are side-by-side two scanlines down. The two luma pixels in the
  intermediate scanline are from the other field, and so share a
  different chroma pixel with two luma pixels two scanlines away. All
  this confusion makes it necessary to have vertical crop dimensions
  and offsets be multiples of four. Horizontal can stay even.
  </para>

  <para>
  For telecined video, I recommend that cropping take place after
  inverse telecining. Once the video is progressive you only need to
  crop by even numbers. If you really want to gain the slight speedup
  that cropping first may offer, you must crop vertically by multiples
  of four or else the inverse-telecine filter won't have proper data.
  </para>

  <para>
  For interlaced (not telecined) video, you must always crop
  vertically by multiples of four unless you use <option>-vf
  field</option> before cropping.
  </para>
  </listitem>

<listitem><formalpara>
  <title>About encoding parameters and quality:</title>
  <para>
  Just because I recommend <option>mbd=2</option> here doesn't mean it
  shouldn't be used elsewhere. Along with <option>trell</option>,
  <option>mbd=2</option> is one of the two
   <systemitem class="library">libavcodec</systemitem> options that
  increases quality the most, and you should always use at least those
  two unless the drop in encoding speed is prohibitive (e.g. realtime
  encoding). There are many other options to
  <systemitem class="library">libavcodec</systemitem> that increase
  encoding quality (and decrease encoding speed) but that is beyond
  the scope of this document.
  </para>
  </formalpara>
  </listitem>

</orderedlist>

</sect2>

</sect1>

</chapter>