This is a subject that I wish I had not started reading about! Before I had no idea that PC's use a different colorspace to that of, say, a DVD player, and that the way colours are presented on a PC changes depending on what video renderer you use!
So just wondered how other users have tackled this issue?
My concern was banding and crushed blacks when using GBPVR with a digital (LCD) display. I started finding threads like this one
http://www.avsforum.com/avs-vb/showthread.php?t=523614
And I have now managed to eliminate these issues by adjusting my display.
Certainly I have found this subject, along with deinterlacing, to be the most difficult to grasp when it comes to using an HTPC...
Pob
deinterlacing and digital media is the biggest pain in the ass ever
"Viewing video that is set to video levels, meaning that the reference "black" is at level 16 and the reference "white" is at level 235, with room in the 0-15 and 236-255 range for extra data, such as the screenshots taken from DVE here (
http://mistermax.smugmug.com/gallery/429986 ) through Overlay or VMR9 results in the following:
Overlay...
This will get rid of, or "clip" 0-15 and 236-255, showing video levels (16-235) as they should appear, by expanding the 16-235 range to 0-255. This shows level 16 black at level 0 of PC levels, and level 235 white at 255. This stretches out the whole range of values and may create unwanted side effects because it discards or clips any information that may be encoded below/above 16 and 235. It does, however, allow DVDs to be viewed with black/white at the proper level without adjusting the brightness/contrast level of the display itself, which may be necesary due to the uses of the HTPC, constraints of the display, etc. etc..
VMR9...
This will maintain or "pass through" the full 0-255 range, keeping btb/wtw information, any data encoded below 16 and above 235, intact. So, what you have to do in order to calibrate going from 0-255 PC levels to achieve proper 16-235 Video levels for VMR9 DVD playback, is lower the brightness (black level) to show level 16 reference black, the lowest black on a DVD, to appear as "black" on the display (not dark grey, as it appears when the display is set to 0-255), and have all information/levels below that blend in with the black. Then you adjust "contrast" (white level) up so that level 235 reference white on a DVD appears as white, and all information/levels above 235 appear to blend in with the white"