[FFmpeg-devel] [GSoC] Motion Interpolation

Paul B Mahol onemda at gmail.com
Mon Aug 15 23:17:41 EEST 2016


On 8/15/16, Davinder Singh <ds.mudhar at gmail.com> wrote:
> On Tue, Aug 16, 2016 at 1:40 AM Davinder Singh <ds.mudhar at gmail.com> wrote:
>
>> On Sat, Aug 13, 2016 at 8:05 PM Paul B Mahol <onemda at gmail.com> wrote:
>>
>>> [...]
>>
>>
>>> Also, why is there no code for scene change detection?
>>> If scene changes abruptly it will give bad frame.
>>>
>>
>> added scene change detection from framerate filter:
>>
>> https://github.com/dsmudhar/FFmpeg/commit/1ad01c530569dfa1f085a31b6435597a97001a78
>>
>> On Sat, Aug 13, 2016 at 10:41 PM Michael Niedermayer
>> <michael at niedermayer.cc> wrote:
>>
>>> [...]
>>
>>
>>> the motion estimation should already produce a "matching score" of some
>>> kind for every block, its sum is probably a good indication how
>>> similar frames are
>>> the sum probably would need to be compared to some meassure of variance
>>> for the frame so near black frames dont get better matches
>>> a bit like a correlation coefficient
>>> you can also look at
>>> git grep scene libavcodec/mpegvideo* libavcodec/motion_es*
>>>
>>
>> i also tested comparing sum of SBAD score but it gave me mostly false
>> detection.
>> vf_framerate one works even with dark scenes (i reduced threshold from 7
>> to 5) correctly, though it doesn't consider any motion.
>>
>
> i currently duplicate the frames for one loop of interpolations (until next
> frame arrives), blending can also be done.
> https://github.com/dsmudhar/FFmpeg/blob/1ad01c530569dfa1f085a31b6435597a97001a78/libavfilter/vf_minterpolate.c#L1101
> which one you think would be better? frame dup seems perfect to me

What about artifacts with UMH?
See for example this sample:
https://media.xiph.org/video/derf/y4m/in_to_tree_420_720p50.y4m


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