Documentation for VCD/SVCD/DVD encoding, patch by Brendan McCarthy < bmccarthy AH iinet POUM net POUM au>

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@15927 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
gpoirier 2005-07-06 08:39:57 +00:00
parent 3be0851da3
commit 75c4e84e21
1 changed files with 604 additions and 0 deletions

View File

@ -2767,6 +2767,610 @@ codec</title>
</sect2> </sect2>
</sect1> </sect1>
<sect1 id="menc-feat-vcd-dvd">
<title>Using MEncoder 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.
</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.
</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>
</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</entry>
<entry>23.976, 29.97</entry>
<entry>4:3, 16:9 (only for 720x480)</entry>
</row>
<row>
<entry>NTSC DVD</entry>
<entry>352x240*</entry>
<entry>MPEG-1</entry>
<entry>1856 kbps</entry>
<entry>48000 Hz</entry>
<entry>AC3,PCM</entry>
<entry>1536 kbps</entry>
<entry>23.976, 29.97</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</entry>
<entry>29.97</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>23.976, 29.97</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</entry>
<entry>25</entry>
<entry>4:3, 16:9 (only for 720x576)</entry>
</row>
<row>
<entry>PAL DVD</entry>
<entry>352x288*</entry>
<entry>MPEG-1</entry>
<entry>1856 kbps</entry>
<entry>48000 Hz</entry>
<entry>MP2,AC3,PCM</entry>
<entry>1536 kbps</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</entry>
<entry>25</entry>
<entry>4:3</entry>
</row>
<row>
<entry>PAL VCD</entry>
<entry>352x288</entry>
<entry>MPEG-1</entry>
<entry>1150 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>
* These resolutions are rarely used for DVDs because they are fairly low
quality.
</para>
<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.
</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 allows GOP size is 18.
For 25 or 25 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.
</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.
</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>.
</para>
<para>
VCD:
<screen>
-of mpeg -mpegopts format=xvcd
</screen>
</para>
<para>
SVCD:
<screen>
-of mpeg -mpegopts format=xsvcd
</screen>
</para>
<para>
DVD:
<screen>
-of mpeg -mpegopts format=dvd
</screen>
</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.
</para>
<para>
16:9 or "Widescreen"
<screen>
-lavcopts aspect=16/9
</screen>
</para>
<para>
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
</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
</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 acheived using the <option>-srate</option> and
<option>-af lavcresample</option> options together.
</para>
<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.
</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:
</para>
<itemizedlist>
<listitem><para>
<emphasis role="bold">acodec</emphasis>:
<option>mp2</option> for VCD, SVCD, or PAL DVD;
<option>ac3</option> is most commonly used for DVD.
PCM audio may also be used for DVD, but this is mostly a big waste of
space.
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;
<option>mpeg2video</option> for SVCD;
<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.
18 for 30fps material, or 15 for 25/24 fps material.
Commercial producers seem to prefer keyframe intervals of 12.
It is possible to make this much larger and still retain compatibility
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;
up to 2500 for SVCD;
up to 9800 for DVD.
For the latter two formats, vbitrate should be set based on personal
preference.
For instance, if you insist on fitting 20 or so hours on a DVD, you
could use vbitrate=400.
The resulting video quality would probably be quite bad.
If you are trying to squeeze out the maximum possible quality on a DVD,
use vbitrate=9800, but be warned that this could constrain you to less
than an hour of video on a single-layer DVD.
</para></listitem>
</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:
</para>
<para>
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>
</para>
<para>
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 in 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>
</para>
</sect3>
</sect2>
<sect2 id="menc-feat-vcd-dvd-audio">
<title>Encoding Audio</title>
<para>
VCD and SVCD supports 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.
</para>
<para>
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>
</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>
</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>
</para>
<para>
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>
</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.
</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 -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>
</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 -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>
</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 -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>
</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 @ 23.976 fps:
<screen>
mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd -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>
</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>
</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>
</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>
</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>
</para>
</sect3>
</sect2>
</sect1>
<sect1 id="menc-feat-telecine"> <sect1 id="menc-feat-telecine">
<title>How to deal with telecine and interlacing within NTSC DVDs</title> <title>How to deal with telecine and interlacing within NTSC DVDs</title>