[Ffmpeg-devel] [Ffmpeg-devel-old] Re: avi out is buggy

[Michael Niedermayer]

Hi

On Monday 09 May 2005 13:24, Thomas Herrmann wrote:
> Michael Niedermayer <michaelni <at> gmx.at> writes:
> > Hi
> >
> > On Monday 09 May 2005 12:08, Thomas Herrmann wrote:
> > > Hi,
> > >
> > > it seems the avi output of ffmpeg is buggy in the way that AC3 sound
> > > gets out of sync over time. The sound just drifts apart from the video.
> > > This is true too with AAC coded sound, while MP2 seems to be fine.
> > >
> > > To reproduce this I take a MPEG sample containing a MPEG2 video stream
> > > and an AC3 audio stream and do:
> > >
> > > ffmpeg -i sample_w_ac3.mpg -vcodec copy -acodec copy out.avi
> > >
> > > While playing this file with mplayer, the sound starts in time with the
> > > video, but drifts away quickly.
> >
> > stream copy from mpeg to avi isnt synchronizable, mpeg has timestamps,
> > avi does not, so frame drop / audio resampling might be needed but its
> > not possible with stream copy
> >
> > -> bug closed / invalid
>
> Ok, but your answer does not help me to generate usable video file.
>
> I was asking what output format and/or ffmpeg options should I use to
> transcode a MPEG file containing a MPEG2 video stream and an AC3 audio
> stream to a video file (avi, mpg, mov, ... ???) containing a h264 video
> stream and a ac3/aac audion stream?
>
> I tried:
>
> ffmpeg -i sample_w_ac3.mpg -vcodec h264 -acodec copy -sameq -hq out.avi
>
> which leads to asynchronous output, so does:
>
> ffmpeg -i sample_w_ac3.mpg -vcodec h264 -acodec aac -sameq -hq out.avi

try -async 100 or similar, if it doesnt help upload enough of the source video 
so its reproduceable (to ftp://mplayerhq.hu/MPlayer/incoming and tell us the 
filename)

[...]
-- 
Michael