[MPlayer-dev-eng] [PATCH] Coring filter

[Jan Paul Schmidt]

Am 27.06.2005 um 09:52 schrieb Guillaume POIRIER:

> Let me see if I understand correctly what this filter is about:
> you give it a threshold, and all areas that are below that threshold
> get all painted with the same black.

Yes.

> One benefit I see from this kind of filter is to reduce the amount of
> information that a video encoder might have to encode, pretty much
> like lumi_mask, but at the filter level...
> Am I right about this?

I guess you rather mean dark_mask? I don't know how dark_mask works 
internally, but I think it more affects quantization for darker areas 
instead of just blacken things.

The coring filter can be extended easily to do the same to high levels. 
If someone needs this, this would be no problem. It would make the 
filter look less trivial ;o)

> What other practical useful example may you come up with?

If you kill chroma and use some higher values, you can emulate the look 
of a old black and white observation camera ;o)

Coring is a cheap denoise filter. How much it affects compressability I 
can't tell at the moment. It maybe make it worse, because you can 
create really hard edges with it. It all depends on how it is used. But 
it makes the picture look better under certain circumstances. At least 
for me.

To avoid the hard edges with extreme settings, one can add some 
smoothing around the treshold. Don't know if it is worth.

I just started to mess around with it myself. After googling I found, 
that some people use this kind of filter. As I did not find one for 
*nix, I implemented it for MEncoder.

jps