I was wondering if any video specification has support for transparency in the video image? I do see a vague reference of to alpha composting support in the H.264/MPEG-4 AVC article on wikipedia but it was unclear whether the "Auxiliary pictures" allow for identifying regions of transparency.
I am try to create a video display that will have something layered beneath the video and want it to show through. Is there standards support for this already? Does VLC support this in some fashion? (Such as chroma key filtering if not in any standard?)
Please note that this is not transparent controls or semi-opaque windows but that each frame of the video will have areas that are transparent. One test case would be using two video stream and have the one with transparency layered over top of the other.