[FFmpeg-soc] vf_overlay with transparancy

[Vitor Sessak]

Zeger Knops wrote:
> Hi,
> 
> Since I needed vf_overlay to use luminance based transparancy I've written a small extension for the overlay filter to accomplish this.

Thanks for the patch, but this is not what I see as the best way of 
doing it. I think that the right way to accomplish this is with the 
following filter chain

input 1  ------------------> overlay_with_alpha --> output
                           /
input 2  --> add_alpha --/

A patch to add alpha handling to vf_overlay.c has been posted to 
ffmpeg-devel (search for the thread "Support alphablending in the 
overlay filter"). The add_alpha filter has also been posted to 
ffmpeg-devel, see vf_alpha.patch in thread "[RFC] Alpha support".

Finally, to generate a lisible patch, I suggest you go to the soc tree 
directory and use "svn diff".

-Vitor