[FFmpeg-devel] ogg encode issues
Frank Barchard
fbarchard
Tue Jun 30 18:32:01 CEST 2009
While encoding Ogg videos I've run into a several issues or limitations with
ffmpeg's version (as of 19289)1. vorbis audio is limited to 48khz
2. size limitation - 1920x1080 does not work. 1920x800 does.
3. ffmpeg ogg mux produces files that don't play back at correct rate. 4.
ffmpeg ogg vorbis audio produces corrupt files
more details for each
1. vorbis audio is limited to 48 Khz.
ie this works
ffmpeg -y -i color48000_2.wav -acodec libvorbis color2.ogg
*This fails
ffmpeg -y -i color96000_2.wav -acodec libvorbis color2.ogg
Error while opening encoder for output stream #0.0 - maybe incorrect
parameters such as bit_rate, rate, width or height
oggenc can do 96k
oggenc2 -o color1.ogg color96000_1.wav
2. size limitation - 1920x1080 crashes ffmpeg encoder. 1920x800 works okay.
this fails
ffmpeg -y -s 1920x1080 -r 29.97 -i red.1920x1080_30Hz_P420.yuv -b
4000000 -vcodec libtheora -an red.ogv
this works
ffmpeg -y -s 1920x1080 -r 29.97 -i red.1920x1080_30Hz_P420.yuv -s
1280x720 -b 2000000 -vcodec libtheora -an red.ogv
3. ffmpeg mux produces files that don't play back at correct rate.
This fails
ffmpeg -y -i sync2.ogg -i sync.ogv -vcodec copy -acodec copy sync2.ogv
but this works
oggz-merge sync2.ogg sync.ogv -o sync2.ogv
both produce playable files, but the ffmpeg one is out of audio
sync... framerate goes fast for awhile, then slow.
ie use mplayer to test
mplayer sync2.ogv
4. ffmpeg for ogg audio produces corrupt files
This has improved recently... it used to say the files were produced
with a buggy encoder. But there is still an issue relating to audio.
It works on most files, so its data sensitive.
This fails:
ffmpeg -y -i sync2.wav -acodec libvorbis sync2.ogg
oggz-merge sync2.ogg sync.ogv -o sync2.ogv
oggz-info sync2.ogv
Content-Duration: 00:03:00.180
Theora: serialno 0000000000
6610 packets in 6610 pages, 1.0 packets/page, 0.993% Ogg overhead
This works:
oggenc2 -o sync2.ogg sync2.wav
oggz-merge sync2.ogg sync.ogv -o sync2.ogv
oggz-info sync2.ogv
Content-Duration: 00:03:00.180
Theora: serialno 0000000000
5403 packets in 5403 pages, 1.0 packets/page, 0.885% Ogg overhead
Video-Framerate: 29.970 fps
Video-Width: 720
Video-Height: 480
Vorbis: serialno 0000029728
10054 packets in 42 pages, 239.4 packets/page, 8.086% Ogg overhead
Audio-Samplerate: 44100 Hz
Audio-Channels: 2
*
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