DXVA2 and Nvidia color inconsistencies
#1
Update 2: Problem solved! While the problem does occur with either "Limited (16-235)" or "Full (0-255)" set in the Nvidia Control Panel (NVCP), it does NOT occur when that whole page is set to "With the video player settings". This means I can't make Frodo consistent with WMC when using Video Levels, because AFAIK, Frodo only supports PC Levels for video playback when DXVA2 is disabled. The bad news is that to use PC Levels and get a satisfactory calibration for my TV, I need to adjust Contrast and Brightness in the NVCP in addition to the TV controls, which takes me back to square one WRT the color problem because I have to enable "With the Nvidia settings" and thus the dynamic range setting, and I also become somewhat inconsistent with my video devices that don't support PC Levels, like my BD player. The good news is, Gotham has a new feature for using Video Levels, and that seems to solve the color problem without me needing to change my calibration. So thanks for implementing that! To be clear, I now set the NVCP to "With the video player settings", enable Gotham's new "Use limited color range (16-235)" option, and I'm good to go, consistent with WMC and my BD player but without these subtle color shifts that occurred after stopping the first video of a viewing session.

Update 1: The same thing happens in WMC. It does not appear to happen with my Intel i5-4670 graphics. So it looks like this may be a pure Nvidia bug. I'm going to try earlier drivers and see if they help. While it doesn't appear to be a problem due to XBMC, it can still affect the appearance of colors for DXVA2 users as you start and stop videos and go in and out of windowed mode.

---Original message below---

I recently noticed some subtle changes in color while watching Family Guy MKVs, in particular Peter's skin tone in living room couch scenes. I've verified this with several episodes, and for each episode, I am of course taking measurements at the same point in the show. XBMC 12.2 is configured to DXVA2, rendering method Auto, and my video cards are Nvidia GT430 and GTX460 in two different machines, both running driver 331.82 in Windows 7 x64 and connected to the same TV. The Nvidia Control Panel settings don't affect this behavior, and the only difference there is that the 430's video dynamic range is configured as "Limited (16-235)" while the 460 is "Full (0-255)". Here's my reproducible procedure along with the colors I measured in Calman with my i1 Display Pro III and the RGB values from screenshots I took for my HTPC, which contains the GT430 (the values are different for the GTX460, but the overall effect is the same).

1. Start XBMC and resume Family Guy.
x .4146
y .3693
Y 15.12
RGB 229, 173, 144

2. Stop Family Guy and resume it. Peter (and Chris) look a little pink compared to (1).
x .4102
y .3544
Y 15.27
RGB 233, 172, 153

3. Stopping and resuming Family Guy repeats (2) as many times as I do it.

4. Switching XBMC to windowed mode and back to full screen (sometimes) restores the startup state (1).

5. Exiting XBMC restores the startup state (1).

State (2) is the one that is consistent with my Sony S5100 BD player when playing these files from a thumb drive. I can cause XBMC to start and stay in (2) by disabling DXVA2 and enabling DXVA as the renderer; that latter bit keeps XBMC respecting the video settings in the Nvidia Control Panel, which to be brief, provides the same consistency for my HTPC with WMC and my BD player as DXVA2/Auto does. The only thing that avoids the problem is disabling DXVA2; leaving it enabled and varying the rendering method does not help.

Any ideas? Any potential downside to disabling DXVA2 and using DXVA as the renderer compared to my former DXVA2/Auto settings? The AVS HD 709 Black Clipping and other such patterns seem to check out, but I haven't run it this way for long and wouldn't have noticed any subtle video glitches.
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DXVA2 and Nvidia color inconsistencies - by crawfish - 2013-12-20, 23:46


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