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

[Jean-Daniel Dupas]

Le 1 f?vr. 2011 ? 18:05, Michael Niedermayer a ?crit :

> On Tue, Feb 01, 2011 at 06:01:06PM +0100, Jean-Daniel Dupas wrote:
>> 
>> Le 1 f?vr. 2011 ? 17:44, M?ns Rullg?rd a ?crit :
>> 
>>> 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.
>> 
>> If it was reliable, why ffplay and ffmpeg had to implement guessing in the first place ?
> 
> Because mans didnt  had the power to stop us from fixing bugs and writing
> working code back then. Now he has it, remove all guessing code welcome non
> functional ffmpeg
> 

OK. 

Note for myself, the discussion about "approving patch that partially fix an issue, even if it is not the perfect solution" was about videolan.org repository, not the ffmpeg.org one.


-- Jean-Daniel