[Ffmpeg-devel] [PATCH] fix frame duration computation in find_stream_infos

[Baptiste Coudurier]

Hi

Michael Niedermayer wrote:
> Hi
> 
> On Fri, Mar 09, 2007 at 11:34:08PM +0100, Baptiste Coudurier wrote:
>> Michael Niedermayer wrote:
>>> Hi
>>>
>>> On Fri, Mar 09, 2007 at 09:51:44PM +0100, Baptiste Coudurier wrote:
>>>> Hi
>>>>
>>>> Michael Niedermayer wrote:
>>>>> Hi
>>>>>
>>>>> On Fri, Mar 09, 2007 at 05:42:48PM +0100, Baptiste Coudurier wrote:
>>>>>> Hi
>>>>>>
>>>>>> $subj.
>>>>>>
>>>>>> I guess there is a typo here. Is it correct ?
>>>>>> last_dts should be updated when duration is present.
>>>>> no its no typo, this improves accuracy IIRC
>>>>>
>>>> ok, I misunderstood the code then.
>>>>
>>>> wrong_frame_rate.mp4 in incoming:
>>>> Stream #0.0(eng): Video: mpeg4, yuv420p, 352x288, 49.67 fps(r)
>>>>
>>>> should be 16.38 (quicktime),
>>> just because QT says it, doesnt make it correct ...
>> well, just because ffmpeg says it, neither.
> 
> of course not, the real_frame_rate thing is just a guess and the
> doxy says so IIRC
> 
> 
>>> 16.38 does not look like a likely framerate at all
>> 49.67 neither.
> 
> of course, 49.67 is nonsense
> 

I was still thinking about this issue, and since mov demuxer knows all
durations/timestamps after read_header, should it set r_frame_rate to
the correct value ? How would you see it ? I don't really get
r_frame_rate meaning since it is meant to be exact, but only take a few
durations into account.

like total_frames * timescale, total_duration ? But that seems to be
average frame rate.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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