[MPlayer-users] Better ways to remove the logo?

[galenz at zinkconsulting.com]

Hello,

I like to get rid of logos when encoding HD broadcasts. The problem is  
that the results are not terribly spectacular, especially on mixed  
bright/dark backgrounds.

Using the delogo filter with xy coordinates works, but creates a  
large, square block. The result is that much more data must be  
interpolated than is really necessary, and the regular edges with  
corners tends to be more easily picked up visually.

Switching to the remove-logo with a mask image reduces the amount of  
area that needs to be interpolated, but the results are inferior,  
creating strange patterns. Frustratingly, instead of the results being  
better than a simple delogo filter, they are often worse! Strange  
angular effects develop and such. Color gradients are disrupted much  
more than with the delogo filter.

Why can't the same algorithm be used for remove-logo as is used for  
delogo? This alone would offer a modest quality improvement.

While I understand that there's not a lot that can be done for  
interpolating missing data dramatically better, we only need to keep  
terribly egregious effects from developing due to the motion in most  
video and the perceptual quality would increase markedly.

It seems like the delogo filter could benefit from "line/area  
detection" code. For example, if even a small corner of the delogo box  
is a very different color than the rest, the entire box's color can be  
polluted. Simple code that detects the vague "flow" of a line or color  
area (e.g. straight line crossing through box, circle intersecting  
part of the box, etc.) would do wonders for solving this problem.

Another possibility (in combination with the above or alone) to help  
improve the filter would be motion tracking. Obviously, we don't need  
anything exact, just general color regions. Motion compensation and  
detection code is extremely well implemented within video compression  
and deinterlacing. Why not leverage a bit of that code to improve the  
logos?

All we need to do is get the rough shapes and brightness/darkness  
right and the noticeability of the logo masking areas will drop very  
close to zero for the average viewer.

-Galen