[Theora] Video and audio not in sync

RC rcooley at spamcop.net
Sat Apr 30 18:56:59 PDT 2005

On Sat, 30 Apr 2005 20:50:37 -0400
Sal Valente <svalente at mit.edu> wrote:

> So the trick, I assume, is to encode the mpeg using
> an encoder that doesn't always write one output frame per one input
> frame, but instead always generates 24 output frames per one minute of
> input frames, calculated on-the-fly.  The following programs do not do
> that:
> ffmpeg
> ffmpeg2theora
> mplayer -vo yuv4mpeg

Actually, someone submitted a patch to mplayer a while ago, that gives
it the "-ofps" option that works similarly to mencoder.  It was designed
to make -vf divtc work with mplayer. It was never accepted, but it
should be in the archives if you wish to try it. 

> It appears that mencoder does what I need, but unfortunately, mencoder
> doesn't encode to any interesting codecs. 

Is that a problem?  Output to some lossless codec (or very high bitrate
MPEG-2, etc.), then encode from that file into theora.  You can use a
fifo instead of writing the whole file to disk...

It would be nice if mencoder got theora support (doesn't need to be
through libavcodec), but it doesn't have Vorbis or even Ogg support yet
either, so it would take a lot of work.

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