I am trying to modify omxplayer to allow for a alpha/transparency mask for videos. In the optimal scenario, you would specify multiple " --transparent 'x1 y1 x2 y2' " options to allow for specifying transparent regions within the playback viewport defined by "--win".
I am digging into omxplayer code and OpenMAX IL spec. As far as I have understood up to now, the only way to achieve this is by preparing the mask in a buffer and using OMX_IndexConfigCommonColorBlend or OMX_IndexConfigCommonPlaneBlend to blend the the two components outputs.
Since I have zero experience with OpenMAX, is the above correct? Would this affect video playback performance/load? Has anyone done anything similar?