for video, a film grain effect could easily be a Steganography channel, not just watermark. the interactions with various re-encoding techniques (especially cha

for video, a film grain effect could easily be a Steganography channel, not just watermark. the interactions with various re-encoding techniques (especially chaining different ones and pass around videos do) will cut into capacity but i expect some coding could be constructed to give you enough bits for a useful signature. Makes me want to experiment with streaming services and see how unique the streams they serve are and what might be hidden within.