[Ffmpeg-devel] [Ffmpeg-devel-old] Re: avi out is buggy
Mon May 9 15:06:22 CEST 2005
> Since the posted commands produce a desynched avi from a file that is
> said to play correctly in mplayer, one could deduce that the streams in
> it are not inherently synchronized, but the synchro is maintained by the
> timestamps themselves; in other words, as Michael wrote, at places there
> are too many or not enough audio samples. Obviously that cant be done if
> But if the audio is decoded then re-encoded, then ffmpeg
> *should* be able to produce well-synchronized raw elementary streams at
> the intermediate stage (after decoding, before encoding) or else the A/V
> synch code is buggy.
Yes, and this does in fact work with "-async 1" (or perhaps higher,
"-async 50". I have used this successfully.
> What it does exactly is not 100% clear from the
> source, ffmpeg.c does not seem to make up its mind clearly whether
> timestamps or rate-times-count hold the truth. That is, the intermediate
> stage itself is not a well-specified format, the input and output
> formats contaminate it.
I do not see what you mean here -- the "intermediate stage" is raw
data frames (16bit per channel for audio, AFAICS), but for
synchronization purposes _only_ the timestamps hold the truth (also
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