[FFmpeg-devel] About guess_correct_pts / AVFrame.best_effort_timestamp

Michael Niedermayer michaelni
Thu Feb 17 03:02:18 CET 2011

On Wed, Feb 16, 2011 at 09:51:38PM +0100, Nicolas George wrote:
> * Almost any absurd combination of problem that can be imagined actually
>   exist. The most obnoxious one is probably AVI: the AVI format has no
>   timestamps whatsoever. The best timing information it provides is the
>   assumption that each packet code for exactly one frame, and each frame has
>   exactly the same duration. Thus, the packet number can more or less be
>   used as a DTS, but that's all.

I had a avi file that had an hour of audio in a single packet.
mplayer could actually play it and even seek in it :)

also if you consider avi obnoxious.
mpeg-ps/ts stores not frames but randomly cut pieces of bytestreams
aka each packet can be from a single byte to dozends of frames with the end
points cut. and timestamps only need to be stored once every 0.5 seconds that
is not on every frame and not even on every packet.
that together with B frame reorder stuff and variable duration frames is
alot of fun


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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