[FFmpeg-devel] [PATCH 1/1] segafilm: fetch duration from the container

Paul B Mahol onemda at gmail.com
Fri Apr 20 19:09:43 EEST 2018


On 4/20/18, James Almer <jamrial at gmail.com> wrote:
> On 4/20/2018 12:34 PM, Gyan Doshi wrote:
>>
>>
>> On 4/20/2018 8:35 PM, James Almer wrote:
>>
>>
>>> I don't understand the reasoning to invert the logic here. The current
>>> behavior is clearly not right. We're marking Inter coded frames as key
>>> frames and Intra coded frames as non keyframes.
>>
>> This behaviour was how it was originally. See the sample attached to
>> #7091. Before inversion, first frame on that file is not marked as KF
>> but all remaining frames are.
>>
>> If you streamcopy the FATE sample to a new CPK starting at a frame
>> currently not marked as KF, with -copyinkf, you should see
>> artifact/incorrect decoding in the output.
>
> Wouldn't this hint that the file in question is broken? I see it was
> generated with our muxer, which is indeed setting keyframes wrong.
>
> In line 72 from segafilmenc.c I see
>
>         if (pkt->keyframe)
>             info1 |= (1 << 31);
>
> So basically, a fifteen years old demuxer got its logic inverted to
> match the behavior of an evidently faulty month old muxer.
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Take real sample from game, if first frame is not marked as keyframe,
demuxer is wrong.


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