Custom Resolution Utility (CRU)

[ashlar]

Hi! First of all thanks to ToastyX for continued support of this utility.

I finally decided to use it when trying to fix the clock deviations (audio/video) for my HTPC. Being fed up with Nvidia messy custom resolutions handling, I was advised about CRU. And here I am

My system is Win 8.1 x64, I use a Nvidia GTX 660 (361.75 drivers, it being an HTPC I try to avoid updating needlessly) connected to a Pioneer Kuro plasma LX-6090 through HDMI (through which audio from GTX 660 is routed too).

Without CRU, the custom resolutions I generated appeared in the Nvidia Control Panel (NCP from here on) on top of all others, under the Custom entry, with other resolutions I used (1080p 50Hz already had perfect timing by default, for instance) appearing under the "Ultra HD, HD, SD" entry, just below.

In CRU I found my plasma as the single device connected, I proceeded to download all Detailed resolutions and Standard resolutions I found there.

I then created a 1920x1080@60Hz detailed resolution (main screen) and then went to Custom extension block.

In Custom extension block I added the other resolutions I needed under detailed resolutions (Extension Block screen) and I added HDMI support and Audio formats under the Data blocks entry (Extension Block screen). I did this by importing the files downloadable from the opening post, modifying only the DSD entry under bitstreaming formats supported (as my AVR doesn't support DSD bitstreaming if I'm not mistaken, anyway it's not relevant to my problem ).

OK, OK, OK, Restart64.exe. Custom resolutions looking good (some trial and error for some refresh rates but I ended up with what I wanted), audio working. Great! Resolutions created with CRU appeared in NCP under the PC entry. No more "Ultra HD, HD, SD" entry there.

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.