[FFmpeg-devel] About guess_correct_pts / AVFrame.best_effort_timestamp

Nicolas George nicolas.george
Thu Feb 17 21:48:33 CET 2011

Le nonidi 29 pluvi?se, an CCXIX, Luca Barbato a ?crit?:
> I don't see why. Cramming half demuxer in libavcodec doesn't sound
> correct.

That is the other way around: determining the PTS when there is none
requires cramming a significant part of a decoder (the parser) in the

Do you agree with the following principle:

A demuxer that decodes perfectly the information in its supported format but
does not examine the payload data at all should be acceptable.


> The main flaw is assuming that libavcodec, with the data it has, can do
> something reliable.

Why should lavf be able to do it then? lavc has more information than lavf,
since it has all information extracted by lavf plus everything in the

> I understood your point of view but please understand that gst, vlc,
> tcvp and even mplayer might rather have lavc not do this kind of work.

I did not manage to find where mplayer finds the timestamp. As for VLC, at a
first glance, it uses obsoletes API to do mostly the same thing as
guess_correct_pts, with its own load of special cases and heuristics.


  Nicolas George
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