Calibrate for 0-255 or 16-235?

IMO, yes. Since video cards output RGB 0-255, it makes more sense to output this and avoid additional conversions. As long as every other connected device can output 0-255 and your display supports 0-255, that's what I'd recommend.

Be careful with 'Auto' settings... some displays don't correctly identify the input range (my ST50 for example). I would force 0-255.

The projector may accept 0-255, but I would imagine that it converts to 16-235.

The best way to do things from my understanding with your HTPC is:

GPU: 0-255
video player: 16-235
projector:16-235

This should prevent any video level conversion. However, you'll have to set the projector brightness according to your video player, and since it's set to 16-235, this means that anything else you do on your HTPC is going to have crushed blacks.

That method allows you to view blacker than black and whiter than white information in videos. But as you said, it will clip detail in the desktop because the levels aren't matched. My config sets everything the same so the levels are all matched, but you can't see BTB/WTW detail. If you have no regards for the desktop, then that setup is ideal, yes. Most detail above 235 are from ringing artifacts (see this post) and detail below 16 won't be visible because you won't be able to see it on a set with a properly set brightness. So it's a matter of compromises.
Edited by rahzel - 1/22/13 at 7:49pm

Rahzel, when you say my config sets everything the same levels, you mean 16-235 for GPU, video player and display. is that true?
Then the only diffence between your sets and the one commented by ttnuagmada is that in this last option we are crushing other than video player in the htpc?

No, I mean 0-255 for the GPU, video player and display. But setting everything to 16-235 will be essentially the same. I'm against setting everything to 16-235 because then there's extra conversions. AFAIK, there aren't any GPUs that can output native 16-235 and 16-235 will always get expanded to 0-255 regardless, so setting everything to 16-235 will cause the GPU to scale up to 0-255, then back down to 16-235. Setting the player to output 0-255 will avoid this extra step. The only benefit to ttnuagmada's setup, is that you can see BTB/WTW detail, but the downside is that you clip levels below 16 and above 235 in the desktop.

Setup 1 (my setup):
GPU outputs 0-255
Video player outputs 0-255
Display expects 0-255
Desktop and videos have matched levels where 0 is black and 255 is white, and the display is expecting this range. Videos get expanded from 16-235 to 0-255 once. The desktop gets no conversion because the GPU is outputting native 0-255.

Setup 2:
GPU outputs 16-235
Video player outputs 16-235
Display expects 16-235
Again, desktop and videos have matched levels and the display is expecting a range of 16-235 where 16 is black and 235 is white. Videos get expanded from 16-235 to 0-255, then back down to 16-235. The GPU converts 0-255 to 16-235 for the desktop. Result looks essentially the same as setup 1, but with more conversions.

Setup 3 (ttnuagmada's setup):
GPU outputs 0-255
Video player outputs 16-235
Display expects 16-235
Now the display expects a range of 16-235, but the desktop is outputting 0-255. So videos will look right, but the desktop will clip levels below 16 and above 235. Again, this is the only way to be able to see WTW/BTB detail on a computer.
Edited by rahzel - 1/23/13 at 2:45am

Thank you very much Rahzel for the clear explanation.
This used to be a confusing issue.

I use option 2, because it matches all my other video components.

Also the video isn't really getting scaled and re-scaled. The video driver gets the dxva input and then formats when it does the final write into the buffer.

So would there be no difference in video quality between option 2 and 3? I've always run option 3, because I was under the impression that it was the only way to do things without any level conversion.

There's really no difference in any of the options when it comes to video. But option 1 or 2 make the most sense to me.

I use option 2!

I agree that 2 makes the most sense in general, I just figured that 3 would be the optimal choice if video was the only concern.

Never output anything other than RGB 0-255 from a PC source unless you have no other option. Everything other than video is rendered natively in the 0-255 range, so you are compressing levels to achieve a 16-235 output. Most video cards do not do this with especially high precision and will introduce banding into the image.

If you use a high quality video renderer (e.g. madVR) there will be no difference in video quality from the levels expansion from 16-235 to 0-255. You will "lose" below black and above white information, but those are not valid ranges for video, and should only be seen on test discs, not commercially released content.

I do the same. The only purpose of my HTPC is for stored movies/TV shows. What this does to the desktop or other non-video content is irrelevant in this usage scenario.

I agree 100%. I would only output 16-235 if you have to (ie your other components can't output 0-255, like sotti's case). Anyone who cares about quality should be using madVR, too.

In my situation (option 3), my other components are fine, because i calibrate brightness and contrast to MPC/MadVR (16-235) and not the desktop. Unless I'm missing something, if video playback was the only concern with an HTPC, option 3 would be the best option, even if you have other video components, because you avoid any video level conversions, while still having your TV brightness set correctly for a cable box/Blu-ray player.

I've checked brightness against my PS3 and they match up perfectly, everything seems fine on my cable box as well.
Edited by ttnuagmada - 1/24/13 at 10:32pm

0-255 output from the PC, and 0-255 from madVR will look better because it has more bits to work with to do the YCC>RGB conversion, colorspace conversions, gamma/3DLUT processing etc.

Won't that all be negated by my TV having to convert it to 16-235? I was under the impression that having the TV do a level conversion is what you want to avoid most.
Edited by ttnuagmada - 1/25/13 at 12:08pm

Your TV processes at much higher bit depth, and as it processes the signal, it will eventually be turning into a full range signal at some point in the processing.

I guess I've been going about this the wrong way then. Will my calibration still be good if I make those changes, or will I need to touch it up?

When ever you change anything touching up is a good idea.

What I meant about always being converted to full range, is that actual light engine for your display will take 0 for off, and a maximum value(255, 1023, 4096, ect..) for max output.

I appreciate you guys clearing that up for me. I thought I had this all figured out.

OMG, I thought it was clear after Rahzel answer describing the 3 options, but after a dozen of answers now I'm confused again.
Until now I use option 3 with this config:

GPU: Nvidia - Full 0-255. YCbCr
Video Player:

• player: MPC - option output range 16-235 in renderer settings
• render: EVR-CP - no specific option other than previous AFAIK
• decoder: LAV Video decoder: option RGB output levels 16-235 (I'm not sure if this option has any influence)

Display:

• Plasma: Panasonic PX70E.No specific option. I think it autoadapts.
• Projector: Mitsubishi HC7000. Input:YCbCr

and I'm glad with the results.


Chronoptimist:

1. You say not only output 0-255 (I assume from GPU and MPC) but RGB and not YCbCr. Up to now I've read to output YCbCr from computer. Why RGB?
2. I tried madVR as a renderer. If I set output level to 0-255, I getting the same as EVR-CP with 16-235. But if I set it to 16-235, I can see BTB and WTW. Never get them with EVR-CP but I need to reset brightness and control because with previous EVR-CP settings black is grey and not black. New setting controls are far lower for brightness in order to set clipping patterncorrectly and higher for contrast in order to get same Y value: 35 ftL. Am I going to get the same overall quality and black levels with 0-255 and 16-235 if I set brightness and contrast levels properly?. Is really no difference between them?

Sotti/Rahzel:

What are you saying is that you use option 2 to match bluray or other sources and then you use the same calibration settings for all of them? I've always understood that is better to calibrate each source independently and use its specific settings. Is it reliable to calibrate with HTPC(16-235) or bluray and use these settings for both with the same quality and accuracy?

You should switch to MPC-HC, if you aren't already running it. I would suggest switching to madVR if your system can handle it, as it is much better quality than EVR. This shouldn't make a difference unless LAV is converting from YCC to RGB. Unless you've disabled all the YCC output formats, it should not be doing that. (you shouldn't disable any formats in LAV Video, leave it at the defaults)
I'm unsure if this is too old to have a full range RGB setting. (often labelled "black level") You will have to try it and see.

PCs are different from stand-alone Blu-ray players, and render everything natively in 0-255 RGB. This means that you have a YCC (the video file) to RGB (the player/renderer) to YCC (video card output) conversion if you output YCbCr, and that last step is often done with poor precision. (by the video card) If you use madVR, the first YCC > RGB conversion will be done with very high quality. (16-bit per channel rather than 8/10bpc)

I also disagree with the sentiment that stand-alone Blu-ray players should be outputting YCC too, but if it's 4:4:4 it shouldn't be too bad. It really depends on whether your display processes as RGB or YCC internally - at the end it's always going to end up as red, green, and blue pixels.
It seems most are now using YCC for processing though, which often means throwing away half the chroma resolution - if they process in YCC, it's typically 4:2:2. But you are better to have the display perform that RGB to YCC conversion than the video card, as it's typically done with much more precision.
madVR does not use the "standard" nomenclature that most video players/renderers on PC use. It uses correct nomenclature, which is basically reversed from most other players/renderers. You should output 0-255 to have it do level expansion and clip below-black and above-white information.

Always calibrate each source independently. In an ideal world, all players will be outputting exactly the same levels but that is often not the case. And most displays should not need recalibrated when switching between 16-235 and 0-255 output, but you will have to check it.
Edited by Chronoptimist - 1/27/13 at 7:19pm

Thank you Chronoptimist.

I'm using MPC-HC.
I'm goint to try this settings today:

• GPU: RGB, 0-255
• Renderer: madvr, 0-255
• Video player: mpc-hc
• Display: No option for Plasma Panasonic. RGB for Mitsu projector.

I'll share the results.

Just sharing my experience. With an ST30 accepting full range from gpu/madvr I was getting color banding issues in fog and gradients that would be many shades different in the green direction. I seemed also unable to calibrate them away as the shades would shift for only a few %s out of the grey scale. Switching to 16-235 output from madvr and setting my tv to standard input range has eliminated the problem. Is this perhaps a problem with the st30s?

Edit: seems I am still getting some problems. Just at different places than before, so my go to scenes to see this problem were not there.
Edited by Shinyav - 2/28/13 at 11:33am