[Ffmpeg-devel] ac3 -> no sound

Justin Ruggles jruggle
Tue Apr 4 03:40:33 CEST 2006


Hello,

Edmund Mergl wrote:
> I'm trying to recode a vob-file retaining the orignal ac3 sound.
> The result is an avi, whithout any sound :-(
> This is the command-line I've used:
> ffmpeg -i test.vob -f avi -vcodec mpeg4 -b 3000 -g 300 -acodec ac3 -bf 2 -s 720x528 test.avi
> 
> Playing the original vob file with xine or mplayer has sound.
> 
> Recoding the vob-file and converting the sound to mp3 is ok:
> ffmpeg -i test.vob -f avi -vcodec mpeg4 -b 3000 -g 300 -acodec mp3 -bf 2 -s 720x528 test.avi
> 
> Only ac3 does not work.
> Here is the output from ffmpeg (source from CVS today, same problem with older versions):
> 
> 
> FFmpeg version CVS, Copyright (c) 2000-2004 Fabrice Bellard
>    configuration:  --enable-shared --enable-gpl --enable-mp3lame --enable-a52 --enable-amr_wb --enable-amr_nb --enable-faad --enable-faac
>    libavutil version: 49.0.0
>    libavcodec version: 51.8.0
>    libavformat version: 50.4.0
>    built on Apr  3 2006 09:48:37, gcc: 4.0.2 20051125 (Red Hat 4.0.2-8)
> Input #0, mpeg, from 'test.vob':
>    Duration: 00:26:10.2, start: 0.280633, bitrate: 5469 kb/s
>    Stream #0.0[0x1e0], 29.97 fps(r): Video: mpeg2video, yuv420p, 720x480, 9800 kb/s
>    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, stereo, 192 kb/s
> Output #0, avi, to 'test.avi':
>    Stream #0.0, 29.97 fps(c): Video: mpeg4, yuv420p, 720x528, q=2-31, 3000 kb/s
>    Stream #0.1: Audio: ac3, 48000 Hz, stereo, 64 kb/s
> Stream mapping:
>    Stream #0.0 -> #0.0
>    Stream #0.1 -> #0.1
> Press [q] to stop encoding
> 
> 
> The first 200 MB of the original vob-file can be found here:  http://www.edmund-mergl.de/test-part.vob
> (in this movie the sounds starts after 2 minutes)
> 
> 
> Edmund

I can't reproduce the problem here. Using latest CVS, the result plays
just fine for me with both ffplay and mplayer.  There is some low-volume
sound right away, and dialog starts after about 3 minutes.  Maybe give a
link to a sample of your output file so the problem can be traced to
either the encoder or your decoder.

-Justin





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