[theora] Impossible to encode this file in sync

xiphmont at xiph.org xiphmont at xiph.org
Mon Mar 1 19:49:29 PST 2010

> In your opinion, is there a way to encode it in theora in sync? Maybe
> transmuxing or doing any preparation on the input file before encoding
> in theora?

I don't know why ffmpeg2theora is not encoding it in sync, but it
seems to me like it would just be a bug..

The mplayer/y4oi route was using container timestamps to calculate
sync (the strategy it always uses for mpeg).  I don't have tools to
see if the mpeg file had conflicting information confusing
ffmpeg2theora.  All I know is that alternate toolchain I tend to use
myself had no trouble.  To encode in sync you either need to drop
audio or pad video at the beginning.  The audio is starting
considerably before the video.  Aside from the initial offset, there's
nothing odd about the file timing.

In a sense dumping the raw yuv/audio from mplayer and using y4oi is
'preparation' before encoding, it's just all happening in a pipe.


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