View Full Version : xvYCC Color range


Robert SawyerIII
01-28-07, 01:06 AM
I have seen many people talk about the color range of the human eye and the range of the original NTSC and RGB formats, but does any one have a chart like this...
http://www.hdtvmagazine.com/images/articles/rgb-color-space.jpg

with the new xvYCC and the old 24bit 1.2a spec both on the chart so we can compare the ranges?

Thanks.

kelpie
01-28-07, 11:44 AM
Weeellll........ I'm not going to give any guarantees, but the photo below that I found on a Chinese language website seems to show what you're looking for.* It doesn't really match up with the HDTV Magazine diagram that you found, however.

http://img.china.alibaba.com/news/upload/chengpin/3_1140399536028.jpg

HTH,

kelpie

*I inferred this because the title of the diagram on Google included "xvYCC" (along with some Chinese characters), and the legend for the diagram showed the smaller triangle as being "TV". Of course I could be all wet.

You can view the page where I found the diagram at http://info.china.alibaba.com/news/detail/v13-d5641372.html. Maybe your Chinese is better than mine. ;)

HDMI_Org
01-30-07, 07:15 PM
This is the CIE "chromaticity" diagram and in this case, the triangles appear to show the difference between the gamut of a 3-laser-based display (larger triangle) and the standard BT.709 color gamut (smaller triangle). The xvYCC gamut includes all (or virtually all, depending upon who you ask) of the entire horseshoe, in other words, virtually all human-visible colors, so it would not be limited to any triangle on this chart.

That's actually the advantage of xvYCC and explains why HDMI chose that standard rather than one of the other "extended" colorimetry standards; xvYCC really does encompass anything that future display technologies might be able to throw at us.

In the laser case, because lasers are pure, single-frequency sources, they exist right at the edge of this horseshoe. If you imagine a 4-laser display with the 4th being 2/3 of the way up the left edge, you can see that lasers have the potential to display a huge portion of the visible colors, much larger than anything else, including LEDs, which, though they are placed outside of the BT.709 triangle, still cannot reach the very edge like lasers.

Robert SawyerIII
02-02-07, 04:44 AM
There is a diagram here that looks like it MIGHT have the second triangle (hidden in the background). If this is supposed to be it, and it is from your HDMI.org site, then can your get a graphic professional to make the xvYCC triangle STICK OUT!

About 1.3 from HDMI.org (http://www.hdmi.org/pdf/HDMI_Insert_FINAL_8-30-06.pdf)