i've read all i can but cant get any real answer. any help appreciated.

I like the explanation that it's a poor man's noise reduction.

See http://www.videohelp.com/glossary?C#Coring

In coring the luminance is separated into its high and low frequency parts and the high frequency part processed so that any pixel with magnitude less than a threshold is set to 0. Any pixel with magnitude greater than the threshold is passed straight through. After this thresholding process the high and low frequency portions are recombined.

The result is noise reduction over areas of roughly constant luminance. If the threshold is set too high, however, the texture of objects is supressed, skin looks like plastic etc.

thanks chris and a.j.

but when coring does touch a pixel, what happens to chroma?

is there an ideal setting? i'm finding ways to reduce noise on my xl-2. it has a lot of detail, but a lot of noise compared to my xl-1. thanks.

<snip> If the threshold is set too high, however, the texture of objects is supressed, skin looks like plastic etc.

Well A. J., there must be a lot of 'high threshhold coring' taking place in Hollywood, judging from what I've seen. :-)

-gb-

AFAIK it is only done to the luma part of the signal because the high frequency components of the chroma components have already been removed i.e. they are much narrower bandwidth signals already.

AFAIK it is only done to the luma part of the signal because the high frequency components of the chroma components have already been removed i.e. they are much narrower bandwidth signals already.
oh ok. i don't really understand video signals in terms of frequencies. only sound.