[FFmpeg-devel] [PATCH] avfilter/vf_overlay: fix alpha blending for planar formats with a transparent background

Marton Balint cus at passwd.hu
Mon Aug 7 22:09:20 EEST 2017


On Sat, 5 Aug 2017, Michael Niedermayer wrote:

> On Fri, Aug 04, 2017 at 10:23:55AM +0200, Marton Balint wrote:
>> When the background had an alpha channel, the old code in blend_plane
>> calculated premultiplied alpha from the destination plane colors instead of the
>> destination alpha.
>>
>> Also the calculation of the output alpha should only happen after the color
>> planes are already finished.
>>
>> Fixes output of:
>> ffplay -f lavfi "testsrc2=alpha=32[a];color=black[b];[b][a]overlay[out0]"
>
> if it is easy, please add a fate test when / after you push this
>

Ok, will do as a second step. I am going to apply this soon.

Regards,
Marton


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