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

Baptiste Coudurier baptiste.coudurier
Fri Mar 9 23:34:08 CET 2007


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.

> 16.38 does not look like a likely framerate at all

49.67 neither.

> also the 20 first durations have a average framerate
> of 16.57 their strict minimum exact frame rate is 1000

average of whole stts is 61.0707
1000/61.0707 ~= 16.37 (quicktime here says 16.37)

> [...]
> 
> to make the code not fail by choosing a multiple rate like 49.67
> get_std_framerate() would always have to return X/Y if it returned X
> for one of its calls that shouldnt be too hard to fix (patch welcome)
> 

I'll try to, once I fully understand it.

-- 
Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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