I just want to post my observations after years of trial & error:
I have a HD2600 with Catalyst 9.3 under Vista, aero disabled.
I'm using "YCbCr 4:4:4" as pixel format and a HDMI cable using the special DVI->HDMI adapter.
I calibrated my 50' Panasonic PZ70E plasma using the free HCFR calibration software and the "Eye-One Display 2" sensor. As patterns I used IRE0 to IRE100 HDTV patterns from www.w6rz.net
under theatertek vmr9 fullscreen mode.
At the time I didn't know that the pixel format "YCbCr 4:4:4" would pass video unaltered, and compress window levels from 0..255 to 16..235. It gave the most natural video to my eyes, with lots of low-key gray shades.
I did a lot of reading on the video vs pc-level topics and also some experiments, and for my display which can input & display 0..255 via HDMI, I recommend using "YCbCr 4:4:4":
- windows RGB levels are compressed to 16..235
How am I sure ? When using the nokia test patterns (ntest.exe) and absolute black corresponds to the lowest background light on the plasma, and 1% is barely visible (you see some grey pixels dithering when you are close to the display), when you switch from "YCbCr 4:4:4" to Full RGB, all shades up to 8% grey are clipped to full black. When boosting the brightness on my display, they become visible again.
Which means my display can display 0..255 RGB via HDMI, but when sent as "YCbCr 4:4:4", windows black is output as IRE0 (16,16,16) & windows white is output as IRE100 (235,235,235) instead of 255,255,255.
When outputing IRE105 video patterns under "YCbCr 4:4:4", the IRE105 bar becomes whiter then windows white! This is only possible if video levels are unaltered and windows levels are compressed. This is not possible when using full RGB where video 16..235 is expanded to 0..255 and non-video is unaltered.
- video levels vs window levels under "YCbCr 4:4:4"
IRE0 is as dark as windows dark
IRE100 is as dark as windows white
IRE105 is displayed as whiter than white
When you swith to full RGB, windows white also becomes whiter as it is now sent as 255 instead of 235 to the PDP ... . But when absolute black is calibrated to IRE0 under "YCbCr 4:4:4", going to full RGB makes the video oversaturated and shades of dark grey (eg suits) are crushed. It looks like artificial augmented blacklevels. When boosting brightness, the crushing disappears.
- no video alterations ?
I see no difference between avivo, vmr9, directx and direct3d in levels using "YCbCr 4:4:4". I tried:
theatertek renderless vmr9
vlc + directx
vlc + direct3d
tmt + avivo -> IRE105 is displayed not brighter than IRE100, but IRE 0 ..100 look the same as above
and using test patternhttp://www.w6rz.net/ramp.zip
I also tested the colors of the demo 'philips colors of miami' and VLC and TMT have exactly the same color decoding, identical between vlc and tmt.
How can I be sure that TMT doesn't first to
16..235 -> 0..255
and then the card remaps to 16..235
as IRE105 is clipped to IRE100 under TMT and not under VLC.
Does avivo support WTW IRE105 ? Or does it clip >IRE100 ?
I also noticed that in more recent drivers, the pixel format option is gone !