[MPlayer-dev-eng] watermark removal

[D Richard Felker III]

On Sun, Nov 03, 2002 at 10:56:13PM +0100, Michael Niedermayer wrote:
> Hi
> 
> On Sunday 03 November 2002 22:50, D Richard Felker III wrote:
> > 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...
> RTFS of virtualdub & filters ;), no i dunno how its added but imho the problem 

I know I can RTFS but I was hoping someone else might already know a
bit.

> might be that mpeg compression causes errors and so even if the removial 
> equation is correct it cant be removed ...

That's a real issue too, but I don't really care too much about those
errors. They'll get killed with a mild gaussian blur, which is
probably necessary on most encodes with watermarks anyway since
they're usually rather low quality to begin with.

> btw, see http://mountains.ece.umn.edu/~guille/inpainting.htm

Thanks, I'll take a look.

Rich