I’m having a rather strange RGB level issue with one of my XBMC HTPCs when using HDMI audio. I don’t think this is really directly related to XBMC, hence I’m posting here.
Platform: Ubuntu 12.04.1 x86, XBMC Frodo RC, Asus GeForce 610 with 313.09 driver
- connected via HDMI to a Denon 4311 AVR
- which in turn is connected via HDMI to a JVC DLA-X70 projector
My goal is to keep the video chain completely in RGB full range. Both the PJ and the Denon provide options for that, and I have explicitely set ColorRange=“FULL” in xorg.conf.
The problem I have now is that this works as expected unless the NVIDIA driver detects HDMI audio. If that happens, the RGB range which arrives at the PJ is always limited, regardless of the options set in xorg.conf and in the Denon. Additionally, if I set ColorRange=“LIMITED” in xorg.conf, it seems that the RGB range is even more limited, suggesting that the conversion is taking place twice in that case.
– when I connect the HTPC to the PJ directly, the RGB range and color space are as expected and can be switched between RGB Full, RGB Limited and YUV via the according xorg.conf settings
– when I connect via the Denon, but use “UseEDID=FALSE” and use custom modelines to avoid having the NVIDIA driver read the Denon’s EDID and therefore detect HDMI audio, switching ColorRange also works as expected
– when I connect a Dune Smart B1 media player via the Denon, switching between Full and Limited Range in the Dune also yields the expected results. This suggests that this is not a general Denon problem.
– in all cases, nvidia-settings -q ColorRange reflects what is set in xorg.conf, not what is being displayed
I have also tried the NVIDIA 310.19 and 304.64 driver with exactly the same results.
I’ve read somewhere in a forum post that the Windows NVIDIA driver would automatically switch to Limited Range RGB when HDMI audio is in use. There is apparently a registry hack to avoid this. This is pretty much the behavior I’m seeing here as well, although nothing like this seems to be documented in the NVIDIA linux driver documentatio.
Is someone perhaps observing something similiar? I’m very interested whether this is a specific NVIDIA/Denon interoperability issue, something specific to the GeForce 610 class GPUs or whether I’m just overlooking something…