[MPlayer-dev-eng] watermark removal

[D Richard Felker III]

I'm working on a watermark removal filter to get rid of those pesky
semi-transparent watermarks that appear on some movies (especially
stuff recorded from tv and/or released by lame encoding groups).
However, I can't seem to figure out quite how to make it work. My
first idea was based on capturing an otherwise all-black frame from
the movie with just the watermark showing, then having the filter use
that for removing the watermark, but things seem to be a bit more
complicated. I can't seem to figure out how the watermarks are
typically applied -- it doesn't seem to be simple addition or
averaging, so maybe it's some sort of weighted average. Any ideas? The
movie I'm experimented on was apparently watermarked with some stupid
virtualdub filter, so perhaps someone knows how that functions...

Rich