[opendtv] Re: All colors of rainbow in new display concept
- From: "Don Munsil" <don@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Sun, 20 Aug 2006 16:27:33 -0700
It's actually not necessary to redefine MPEG to get extended gamut. Both
BT.1361 and Sony's new xvYCC specs allow for extended gamut in the existing
Y'CbCr space. By allowing R'G'B' values that go above 1 and below 0 (in
normalized 0-1 range), you can extend the gamut out to a much larger
proportion of the full color range. And suddenly a large number of Y'CbCr
code values that are currently RGB-illegal become legal.
Y'CbCr has always had a lot of illegal colors, so without having to change
MPEG (or AVC or VC-1) at all, you can get a significantly extended gamut.
Everything works the same. Obviously internally the camera or display needs
to convert the Y'CbCr values to R'G'B' using higher precision than 8 bit,
but that's perfectly doable.
Now, to cover the entire visible range of colors will require even more
gamut extension. It's possible that minor tweaks to Y'CbCr will get there -
maybe 10 or 12 bits with larger head and toeroom. The gamma for R'G'B' might
need to be extended further beyond BT.1361 or xvYCC. I'm not sure what range
of R'G'B' values will get you every visible color.
Don
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]
> On Behalf Of Manfredi, Albert E
> True. And don't forget the distribution chain itself, since everything
> from camera to display is set up for red/green/blue as of today. MPEG,
> for example, whatever version of it, is not going to easily manage a
> zillion new colors.
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