[FFmpeg-devel] [PATCH] Make decoding alpha optional for some codecs.

[Kirill Gavrilov]

Mark Himsley <mark.himsley <at> gmail.com> writes:

> You have to decode the alpha to use the alpha mask any picture content
> which is under transparent regions.
> You cannot display the video correctly without multiplying the alpha with
> the video content
>

Mark Himsley <mark.himsley <at> gmail.com> writes:

> Is this currently done with ffplay (or MPlayer or vlc)?

​
My player supports alpha channel but only for known RGBA formats.
I have just checked what happens when RGBA image converted to RGB using
swscale and unfortunately result is incorrect (alpha just discarded).

I think most universal players based on FFmpeg fall back to swscale when
unknown pixel format appears and current situation looks not good - if I
haven't missed special flags.