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

[Måns Rullgård]

Michael Niedermayer <michaelni at gmx.at> writes:

> 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?

The patch pushes the broken guessing code into lavc, which was up
until now reliable.

-- 
M?ns Rullg?rd
mans at mansr.com