Custom Resolution Utility (CRU)

[ToastyX]

(05-20-2016 11:44 AM)ashlar Wrote:  Unfortunately I soon discovered that colors seemed off. So I went to check Output colour format and Output dynamic range in NCP. And they were as they always have been set up: RGB, Full output dynamic range. But colors were off. I tested them with a gray ramp and I had blacks crushed.
My plasma is set up with automatic colour format detection but moving from auto to the manual settings I discovered that there was a mismatch between what dynamic range the HDMI was "telling" the TV it was sending and the actual color information it was sending.

To cut things short, whereas before I had my whole "reproduction chain" setup for RGB full (and I calibrated my TV as such, being ISF trained and everything) I now have a situation where I have to set RGB Limited, while keeping my TV to auto (which gets the Limited range correctly at that point) but in madVR (a video renderer for video playback) I still need to have the setting "The display expects the following RGB output levels" to PC levels (0-255). If I set it up to TV Levels (16-235), colors become washed out.

Reproduction chain before CRU: NCP set at RGB Full, madVR set at PC Levels (0-255), tv set to Auto
Reproduction chain after CRU: NCP set at RGB limited, madVR set at PC Levels (0-255), tv set to Auto

In both cases desktop colors look right, black and white ramps show correctly only the 16-235 range (which is what the TV had been calibrated to).

Now... why the difference? Not being sure of what happens behind scenes I'm wary of unneeded or wrong color conversions happening.

I can only think of three factors that would cause a color difference:

1. HDMI vs. DVI signals: Since you included HDMI support in the extension block, this shouldn't be a factor.

2. RGB vs. YCbCr: You said you set the color format to full-range RGB, so this shouldn't be a factor. YCbCr is always limited-range.

3. Timing differences: If you're not using the official CEA standard timing parameters, the TV may treat it as a PC resolution and assume full-range RGB, but you're saying it's receiving limited-range RGB. If the video card is sending limited-range RGB when you set full-range RGB, then that's a driver bug. Try using this: http://blog.metaclassofnil.com/?p=83

Other than that, there shouldn't be any color differences.