[Ffmpeg-devel] About A/V Sync problem after transcoding via FFMPEG

Måns Rullgård mru
Tue Oct 24 04:13:08 CEST 2006

"Sean Zheng" <seanzhen at gmail.com> writes:

> Hi, I've transcoded a H.263 V1 Video from FLV by FFMPEG via the
> following command:
> ffmpeg -i flvtest.flv -s 704x576 -f vob -vcodec h263 -acodec mp3 h263pstest.mpg
> I use the VOB encapsulation method (MPEG PS),

Don't do that.  MPEG PS doesn't support h263 video.  The PS muxer
should be fixed to give an error if you try.

> but I find that the Audio and Video isn't synchronized while playing
> the result video.  and the audio is discontinuous.

How do you play that file?  No player I know of will detect h263 video
in MPEG PS, and neither should they.  Does it work with MPEG2 video?

> But if I use the MP4 encapsulation, the Audio and Video is
> synchronized while playing the video:
> ffmpeg -i flvtest.flv -s 704x576 -f mp4 -vcodec h263 -acodec mp3 h263mp4test.mpg
> Any suggestions are highly appreciated.

Use MOV, MP4, or whatever it's called today.

M?ns Rullg?rd
mru at inprovide.com

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