Quelle1)
MEncoder is capable of creating VCD, SCVD and DVD format MPEG files using the libavcodec library. These files can then be used in conjunction with vcdimager or dvdauthor to create discs that will play on a standard set-top player.
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.
Format Resolution V. Codec V. Bitrate Sample Rate A. Codec A. Bitrate FPS Aspect NTSC DVD 720×480, 704×480, 352×480, 352×240 MPEG-2 9800 kbps 48000 Hz AC-3,PCM 1536 kbps (max) 30000/1001, 24000/1001 4:3, 16:9 (only for 720×480) NTSC DVD 352×240[a] MPEG-1 1856 kbps 48000 Hz AC-3,PCM 1536 kbps (max) 30000/1001, 24000/1001 4:3, 16:9 NTSC SVCD 480×480 MPEG-2 2600 kbps 44100 Hz MP2 384 kbps (max) 30000/1001 4:3 NTSC VCD 352×240 MPEG-1 1150 kbps 44100 Hz MP2 224 kbps 24000/1001, 30000/1001 4:3 PAL DVD 720×576, 704×576, 352×576, 352×288 MPEG-2 9800 kbps 48000 Hz MP2,AC-3,PCM 1536 kbps (max) 25 4:3, 16:9 (only for 720×576) PAL DVD 352×288[a] MPEG-1 1856 kbps 48000 Hz MP2,AC-3,PCM 1536 kbps (max) 25 4:3, 16:9 PAL SVCD 480×576 MPEG-2 2600 kbps 44100 Hz MP2 384 kbps (max) 25 4:3 PAL VCD 352×288 MPEG-1 1152 kbps 44100 Hz MP2 224 kbps 25 4:3
[a] These resolutions are rarely used for DVDs because they are fairly low 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.
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 keyint option. 11.8.1.3. Bitrate Constraints
VCD video is required to be CBR at 1152 kbps. This highly limiting constraint also comes along with an extremely 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.
MEncoder has options to control the output format. Using these options we can instruct it to create the correct type of file.
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 vcdimager.
VCD:
-of mpeg -mpegopts format=xvcd
SVCD:
-of mpeg -mpegopts format=xsvcd
DVD (with timestamps on every frame, if possible):
-of mpeg -mpegopts format=dvd:tsaf
DVD with NTSC Pullup:
-of mpeg -mpegopts format=dvd:tsaf:telecine -ofps 24000/1001
This allows 24000/1001 fps progressive content to be encoded at 30000/1001 fps whilst maintaining DVD-compliance.
The aspect argument of -lavcopts 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.
16:9 or „Widescreen“
-lavcopts aspect=16/9
4:3 or „Fullscreen“
-lavcopts aspect=4/3
2.35:1 or „Cinemascope“ NTSC
-vf scale=720:368,expand=720:480 -lavcopts aspect=16/9
To calculate the correct scaling size, use the expanded NTSC width of 854/2.35 = 368
2.35:1 or „Cinemascope“ PAL
-vf scale=720:432,expand=720:576 -lavcopts aspect=16/9
To calculate the correct scaling size, use the expanded PAL width of 1024/2.35 = 432
In order to maintain audio/video synchronization throughout the encode, MEncoder 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 harddup video filter at the end of the filter chain to avoid this kind of problem. You can find more technical information about harddup in the section Improving muxing and A/V sync reliability or in the manual page.
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 -srate option and the -af lavcresample audio filter together.
DVD:
-srate 48000 -af lavcresample=48000
VCD and SVCD:
-srate 44100 -af lavcresample=44100
libavcodec can be used to create VCD/SVCD/DVD compliant video by using the appropriate options.
This is a list of fields in -lavcopts that you may be required to change in order to make a complaint movie for VCD, SVCD, or DVD:
This is a typical minimum set of -lavcopts for encoding video:
VCD:
-lavcopts vcodec=mpeg1video:vrc_buf_size=327:vrc_minrate=1152:\ vrc_maxrate=1152:vbitrate=1152:keyint=15:acodec=mp2
SVCD:
-lavcopts vcodec=mpeg2video:vrc_buf_size=917:vrc_maxrate=2500:vbitrate=1800:\ keyint=15:acodec=mp2
DVD:
-lavcopts vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=5000:\ keyint=15:vstrict=0:acodec=ac3
For higher quality encoding, you may also wish to add quality-enhancing options to lavcopts, such as trell, mbd=2, and others. Note that qpel and v4mv, 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 dc=10 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:
-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:vstrict=0
VCD and SVCD support MPEG-1 layer II audio, using one of toolame, twolame, or libavcodec'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.
For DVD audio, libavcodec's AC-3 codec is used.
For VCD and SVCD:
-oac toolame -toolameopts br=224
For VCD and SVCD:
-oac twolame -twolameopts br=224
For DVD with 2 channel sound:
-oac lavc -lavcopts acodec=ac3:abitrate=192
For DVD with 5.1 channel sound:
-channels 6 -oac lavc -lavcopts acodec=ac3:abitrate=384
For VCD and SVCD:
-oac lavc -lavcopts acodec=mp2:abitrate=224
This section shows some complete commands for creating VCD/SVCD/DVD compliant videos.
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:vstrict=0:acodec=ac3:abitrate=192:aspect=16/9 -ofps 25 \ -o movie.mpg movie.avi
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:vstrict=0:acodec=ac3:abitrate=192:aspect=16/9 -ofps 30000/1001 \ -o movie.mpg movie.avi
If the source already has AC-3 audio, use -oac copy instead of re-encoding it.
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:vstrict=0:aspect=16/9 -o movie.mpg movie.avi
If the source already has AC-3 audio, and is NTSC @ 24000/1001 fps:
mencoder -oac copy -ovc lavc -of mpeg -mpegopts format=dvd:tsaf:telecine \
vrc_maxrate=9800:vbitrate=5000:keyint=15:vstrict=0:aspect=16/9 -ofps 24000/1001 \
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:aspect=16/9 -ofps 25 \ -o movie.mpg movie.avi
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:aspect=16/9 -ofps 30000/1001 \ -o movie.mpg movie.avi
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:aspect=16/9 -ofps 25 \ -o movie.mpg movie.avi
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:aspect=16/9 -ofps 30000/1001 \ -o movie.mpg movie.avi