So I don't claim to be a colour management expert, or an expert in the use of madVR for that matter, but that being said:General Info
The best possible solution for video picture quality should be to calibrate and profile the display in it's native state, and then link the resultant profile to the Rec.709 profile in a 3dlut.
The reality of course, is that it's difficult, if not impossible, to know what the display's native state is. What settings should you use?
Most displays, including all TVs that I'm aware of, must use LUTs in their internal processing in order to give you different picture modes such as 'Standard', 'Game', 'Cinema', 'Vivid' etc. I'm not sure if these modes use 3DLUTs, or RGB LUT curves, but I would suspect it's a 3DLUT of some form or other. It's also important to point out that the display panel probably does not have a native Rec.709 or sRGB response curve, and a LUT of some form is therefore required and used inside the panel anyway.
A 3dlut is able to reduce the size of the gamut of the display, but never increase it, so we can be pretty sure that the mode with the widest gamut has the least 3dlut transformations taking place, and that is therefore the one that I'd pick for calibration and profiling.
HD video content was created and mastered to the Rec.709 standard, which is what most of this thread discussion is surrounding. For video viewing, we want our displays to recreate colours exactly as the content producer / director intended, and the only way to do that is to make sure that each digital value in the video signal produces the correct colour on the display. Using a 3DLUT is common practice in professional content creation, so having this available to us home users, particularly using free software is frankly incredible!
I can't speak to your specific model of TV, but in my LG Plasma case, setting the input name to 'PC' results in slightly less image processing. This is obvious because several of the image processing options are disabled once in this mode, so clearly they're bypassed. This is also the only way of getting a 4:4:4 signal to display on my TV.
Aside from the issues of getting a 4:4:4 output from your graphics card (RGB is always 4:4:4 by the way, and YCbCr can be only 4:2:2 or 4:4:4 according to the HDMI spec, so this is likely not really too big of an issue at all), almost all TVs today convert all input signals to YCbCr 4:2:2 for internal processing, before converting this back again to RGB for display.
The exception to this is the 'PC' mode on LG TVs (and other similar settings on other brands), where the 4:4:4 RGB signal seems to be allowed through and somehow bypasses the 4:2:2 YCbCr -> [Image processing and adjustments] -> 4:4:4 RGB transformations. The limitation here however, is that 'PC' mode only actually works for 60p input signals; as soon as the PC switches to video frame rates (23.976p, 24.0p, 29.97p 30p 50p & 59.94p etc.), the display goes back to using the 4:2:2 YCbCr processing. I have not found a way around this limitation.
I've not mentioned that fact that many LCD TVs have options for adjusting the backlight brightness. In an LED Backlit LCD I looked at a few weeks ago, the backlight output could be increased up to 450 nits, but as you did this, the colour balance went way too cool. In order to achieve something similar to a D65 white point, I had to turn down the backlight quite a bit. Calibration curves (2D LUT) could fix this, but you might be thowing away a lot of the 8-bit signal values in order to do this (and that would also reduce the brightness at least some of the way anyway) so I wouldn't recommend it.
Video content is usually mastered to 100 nits (100 cd/m2) peak brightness, so for video at least, there isn't a need to go brighter than this. If viewing in a bright environment however, you might want to do this.
If you're using your TV mostly for PC gaming, which would typically be at 60p anyway, I'd start by using PC mode to avoid the YCbCr 4:2:2 processing. I'd then set the backlight (if you have an option to adjust it) to be as bright as you'd like, whilst making sure that the white balance doesn't go too far blue (don't touch the white balance controls, only the backlight brightness for this).
Then calibrate using dispcal to (probably) sRGB gamma and (probably) D65 white point. You might however want to decrease the gamma if seeing more shadow detail (bad guys in the shadows) helps you with your games!
If your display has colour primaries that are close to sRGB and Rec.709, then that will already probably give you a pretty accurate image. The calibration curves (2DLUT) created with dispcal should set the white point, peak brightness and gamma curve correctly, and the display has the colour primaries pretty much correct anyway!
Note: As discussed earlier, HD video content assumes Rec.709 standards; I'm really not sure what standards PC game developers / producers are working to, so I really wouldn't know what standard to aim for.
For video content, I'd start with PC mode turned off (though most video content is not 60p, so actually setting PC mode to on or off won't make any difference if you're using madVR's frame rate setting function, or similar), and go through a complete calibrate profile and link process described in my previous post. Personally, I set my graphics card to output 23.976p manually when calibrating and profiling, as my display has a very slightly different gamut at each refresh rate, and most of my content is 23.976p.
You'll have installed the calibration curves with dispwin for use with PC Games, so make sure to disable these when you're doing the profiling.
For best picture quality, use the standard 'collink -a' command rather than collink -H. This will use the calibration curves when creating the 3DLUT for madVR. Set madVR to disable VideoLUT, and to use the 3DLUT you created from your profile. The only downside to this approach is that if you watch a video in a window, rather than fullscreen, you'll notice that the calibration curves are disabled when the video plays; as long as you watch videos in full screen, and shut down your player when you do anything else, this should give you the best result.
If you really do want to multi-task with madVR in a window, then use collink -H instead.
As has been said in previous posts, much of this is trial and error. You're going to have to try various options, check the results and see which option you're most happy with. A bit of understanding as to what is actually going on goes a long way, and Graeme's description a couple of posts ago describes that very well.
I hope that helps!Edited by nezil - 7/17/13 at 3:01pm