[Libav-user] adding digital watermark to mpeg4 video

[Igor R]

> Now we'd like to put a protecting "watermark" on this stream. Just to
> clarify: I don't mean a semi-transparent text over the video, but a
> digital signature of the stream, which would verify its authenticity.
> I know MS WMV format supports such a feature through special
> watermarking DMOs, but as for standard mpeg4 video streams in standard
> containers (avi, mp4 etc) - I haven't managed to find sufficient
> information.
> So I've got several questions: 1) Is it theoretically possible to add
> such a signature to mpeg4 video - either in avi or any other
> container? 2) Is it possible with libav* (with or without recoding the
> original stream)? If yes, what APIs should I look at? 3) If I already
> have a signature, is it possible somehow to store it along with the
> stream, as a metadata?


If all the above is impossible, then what is the correct way to
protect/verify the authenticity of the video in a container?