[FFmpeg-devel] [PATCH] Implement guessed_pts in avcodec_decode_video2.

Michael Niedermayer michaelni
Tue Feb 1 17:37:27 CET 2011


On Tue, Feb 01, 2011 at 12:47:17PM +0000, M?ns Rullg?rd wrote:
> Alexander Strange <astrange at ithinksw.com> writes:
> 
> > On Jan 30, 2011, at 2:28 PM, Nicolas George wrote:
> >
> >> 
> >> Signed-off-by: Nicolas George <nicolas.george at normalesup.org>
> >> ---
> >> cmdutils.c           |   27 ---------------------------
> >> cmdutils.h           |   24 ------------------------
> >> ffmpeg.c             |   14 ++++++--------
> >> ffplay.c             |   10 +++-------
> >> libavcodec/avcodec.h |   20 ++++++++++++++++++++
> >> libavcodec/utils.c   |   43 ++++++++++++++++++++++++++++++++++++++++++-
> >> 6 files changed, 71 insertions(+), 67 deletions(-)
> >> 
> >> This patch moves the guess_correct_pts function from cmdutils to libavcodec.
> >> The feature is available through a new field in AVFrame, guessed_pts.
> >> 
> >> make test and ffplay still work, but I would like to have some more time to
> >> read it carefully, but I have things to do in the next few days, and this
> >> feature was discussed in another thread, so here the current version. It
> >> will conflict with some patches that will certainly soon be applied, so I
> >> will update and submit it again anyway.
> >> 
> >> Regards,
> >> 
> >> -- 
> >>  Nicolas George
> >> 
> >> [..]
> >> +\
> >> +    /**\
> >> +     * pts estimated using various heuristics, in stream time base\
> >> +     * - encoding: unused\
> >> +     * - decoding: set by libavcodec, read by user.\
> >> +     */\
> >> +    int64_t guessed_pts;\
> >
> > It's not quite estimated, it's chosen from either pts or dts.  I
> > think the name should be reassuring - though I can't think of one,
> > just 'timestamp'?
> > Also, the comment should say that clients can rely on this as the
> > time of the frame.
> 
> But can they?  The current code certainly doesn't look reliable to me.

A patch that improves it together with a bugreport that shows an example of
improvment is welcome.

besides in how far is this related to this patch?

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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