Posted by Jukka Aho on 10/11/06 00:48

Richard Crowley wrote:

> "Compatible" color is called that because it is built on the base of
> the original black&white video image. If you know that
> "white" is made of 11% blue and 30% red, you can calculate
> the green as the remainder. Note that this is the proportion
> for NTSC, dunno that PAL/SECAM are exactly the same?

PAL uses YUV, NTSC uses YIQ, and SECAM uses YDbDr.

See

<http://en.wikipedia.org/wiki/YUV>
<http://en.wikipedia.org/wiki/YIQ>
<http://en.wikipedia.org/wiki/YDbDr>

Then there's YPbPr, which is, as far as I know, yet different. (And
YCbCr; its digital equivalent.)

> And if you want to get further in, the "red" and "blue" are not
> strictly those colors,

The Y-R signal can be thought of as the red-neutral-green axis, and the
Y-B signal as the blue-neutral-yellow axis. Or was it the other way
around?

--
znark

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