madVR - high quality video renderer (GPU assisted)

[Oguignant]

Originally Posted by Shiandow

You can leave LAV's output levels on 'untouched', although as far as I know LAV shouldn't ever have to pass through TV-level RGB to MadVR anyway.

Well, I'll start using rgb from now on.

[Asmodian]

Originally Posted by Oguignant

Well, I'll start using rgb from now on.

I just want to add that madVR always outputs RGB so if you set YCbCr output the GPU does a conversion and then the display convets it to RGB again.

[Oguignant]

Originally Posted by Asmodian

I just want to add that madVR always outputs RGB so if you set YCbCr output the GPU does a conversion and then the display convets it to RGB again.

TV always convert any signal to RGB? When I watch a bluray by hdmi also the signal is converted to RGB too?

[Shiandow]

Originally Posted by Oguignant

TV always convert any signal to RGB? When I watch a bluray by hdmi also the signal is converted to RGB too?

Somewhere along the line, yeah. In the end the TV only has red blue and green pixels. It's not actually physically possible to display YCbCr.

[Oguignant]

Originally Posted by Shiandow

Somewhere along the line, yeah. In the end the TV only has red blue and green pixels. It's not actually physically possible to display YCbCr.

I always use ycbcr because I thought it gave better colors and contrast with yellow, cyan and magenta compared to red, green and blue...

And as madvr said that nv12 8bits 4.2.0 , I thought that was the output format ...

My TV has RGBA subpixel, does anyone know what it is?

[Q-the-STORM]

Oguignant: in madVR set PC Levels
in nvidia set RGB full range
in LG set Black Level to high, HDMI input icon to PC and HDMI Ultra HD Colour to On...
that will give you the least amount of conversions and all conversions will be done by madVR and not nvidia or LG...

[Oguignant]

Originally Posted by Q-the-STORM

Oguignant: in madVR set PC Levels
in nvidia set RGB full range
in LG set Black Level to high, HDMI input icon to PC and HDMI Ultra HD Colour to On...
that will give you the least amount of conversions and all conversions will be done by madVR and not nvidia or LG...

@Q-the-STORM I understood. it is exactly how I have my Tv and madvr settings. It is logical to use RGB, because madvr does the conversion to RGB.
But, I really do not see a difference using RGB or ycbcr444. I compared many movies and I can not perceive differences in colors, black or shadows. In fact, I use the same color calibrations in both.

I thought rgb was used with PC monitors and ycbcr444 was for Tv.

[e-t172]

Originally Posted by Oguignant

TV always convert any signal to RGB? When I watch a bluray by hdmi also the signal is converted to RGB too?

A Blu-ray player will typically output YCbCr (directly from the decoded video stream) over HDMI. The TV does the YCbCr → RGB conversion.

Internally, a PC GPU works in RGB only. A PC will typically output RGB over HDMI. The TV just passes its through (hopefully) untouched.

If you enable YCbCr output in your GPU driver settings, the GPU will output YCbCr over HDMI. But internally, it still works in RGB. So what's going to happen is that the GPU will internally convert RGB to YCbCr, then send it over HDMI, then the TV will convert YCbCr back to RGB. The double conversion is pointless, and is likely to degrade quality (especially if there's chroma subsampling going on, or the PC and the TV disagree about which matrix to use).

Putting it all together, here's what happens when using madVR:

GPU driver configured to output RGB: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (RGB)

GPU driver configured to output YCbCr: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (converts from RGB to YCbCr) → TV (converts from YCbCr to RGB)

Hopefully you can see now that the second configuration doesn't make a ton of sense!

[Oguignant]

Originally Posted by e-t172

A Blu-ray player will typically output YCbCr (directly from the decoded video stream) over HDMI. The TV does the YCbCr → RGB conversion.

Internally, a PC GPU works in RGB only. A PC will typically output RGB over HDMI. The TV just passes its through (hopefully) untouched.

If you enable YCbCr output in your GPU driver settings, the GPU will output YCbCr over HDMI. But internally, it still works in RGB. So what's going to happen is that the GPU will internally convert RGB to YCbCr, then send it over HDMI, then the TV will convert YCbCr back to RGB. The double conversion is pointless, and is likely to degrade quality (especially if there's chroma subsampling going on, or the PC and the TV disagree about which matrix to use).

Putting it all together, here's what happens when using madVR:

GPU driver configured to output RGB: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (RGB)

GPU driver configured to output YCbCr: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (converts from RGB to YCbCr) → TV (converts from YCbCr to RGB)

Hopefully you can see now that the second configuration doesn't make a ton of sense!

Yes! Now it is perfectly clear. Now I understand, the result is always RGB.

last question. When the video is 10 bits, in fullscreen exclusive mode, how does it convert? Rgb 8 bits?

[David]

Originally Posted by e-t172

Putting it all together, here's what happens when using madVR:

GPU driver configured to output RGB: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (RGB)

GPU driver configured to output YCbCr: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (converts from RGB to YCbCr) → TV (converts from YCbCr to RGB)

Hopefully you can see now that the second configuration doesn't make a ton of sense!

Most TV do RGB->YCbCr conversion so in the end:


GPU driver configured to output RGB: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (converts from RGB to YCbCr) → TV (converts from YCbCr to RGB)

Only with PC Mode yo can avoid that conversion, but not always.

In the end, with most TV, you can only choose where RGB->YCbCr conversion is done, through GPU or TV.

[Oguignant]

Originally Posted by David

Most TV do RGB->YCbCr conversion so in the end:


GPU driver configured to output RGB: LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (converts from RGB to YCbCr) → TV (converts from YCbCr to RGB)

Only with PC Mode yo can avoid that conversion, but not always.

In the end, with most TV, you can only choose where RGB->YCbCr conversion is done, through GPU or TV.

But I think the best option is to use rgb and avoid multiple conversions.

LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (RGB)

What is PC Mode?

[iSeries]

Originally Posted by Oguignant

But I think the best option is to use rgb and avoid multiple conversions.

LAV decoder output (YCbCr) → madVR (converts from YCbCr to RGB) → HDMI output (RGB) → TV (RGB)

What is PC Mode?

PC mode is a special mode on some TVs which turns off many of it's processing 'features'. On my LG plasma for example, if I name the HDMI input as 'PC', almost all of the 'fluff' like dynamic contrast etc is greyed out.

Unless you put your TV into PC mode, it is almost certainly converting an RGB signal into YCbCr (and probably 4:2:2 or maybe worse, 4:2:0) to do all it's processing, and then converting again to RGB for final display.

In PC mode, you may or may not avoid this conversion process - to use my TV as an example again, in PC mode, all of the stuff I don't use anyway is greyed out, leaving only the basic controls and the CMS, but I have no idea whether it's bypassing this RGB-YCbCr-RGB process, all I know for sure is in PC mode it passes the 4:4:4 test (if not in PC mode, it shows 4:2:2, a clear indicator that it's converting an RGB signal into YCbCr).

[PetitDragon]

@David and iSeries

You two know and talk too much!

[Oguignant]

Originally Posted by iSeries

PC mode is a special mode on some TVs which turns off many of it's processing 'features'. On my LG plasma for example, if I name the HDMI input as 'PC', almost all of the 'fluff' like dynamic contrast etc is greyed out.

Unless you put your TV into PC mode, it is almost certainly converting an RGB signal into YCbCr (and probably 4:2:2 or maybe worse, 4:2:0) to do all it's processing, and then converting again to RGB for final display.

In PC mode, you may or may not avoid this conversion process - to use my TV as an example again, in PC mode, all of the stuff I don't use anyway is greyed out, leaving only the basic controls and the CMS, but I have no idea whether it's bypassing this RGB-YCbCr-RGB process, all I know for sure is in PC mode it passes the 4:4:4 test (if not in PC mode, it shows 4:2:2, a clear indicator that it's converting an RGB signal into YCbCr).

My tv is lg 65ef9500 and has pc mode option. (Disable options like trumotion, noise reduction, mpeg noise reduction, etc). I use PC mode + UHD Deep Color for 4k 60mhz.
I did the 444 test and I passed it. And without PC mode (only HDMI) I also did the 444 test and passed it too...



You say that the RGB signal arrives at the TV and then the TV converts it to yCbCr again? I'm already very confused again ...

[Oguignant]

Originally Posted by PetitDragon

@David and iSeries

You two know and talk too much!

jajaja

[iSeries]

Originally Posted by Oguignant

My tv is lg 65ef9500 and has pc mode option. (Disable options like trumotion, noise reduction, mpeg noise reduction, etc). I use PC mode + UHD Deep Color for 4k 60mhz.
I did the 444 test and I passed it. And without PC mode (only HDMI) I also did the 444 test and passed it too...



You say that the RGB signal arrives at the TV and then the TV converts it to yCbCr again? I'm already very confused again ...

If options like trumotion etc are selectable, it is almost certainly converting RGB to YCbCr for processing. You are lucky enough though that your TV does this in 4:4:4. Either way though, even though a completely RGB chain is theoretically better, you may not even see a difference at a normal viewing distance with normal material (eg as bluray is 8 bit 4:2:0 YCbCr to begin with).

[Oguignant]

Originally Posted by iSeries

If options like trumotion etc are selectable, it is almost certainly converting RGB to YCbCr for processing.

PC mode turns off all image processing options on my TV. I think it shows the RGB signal without re-processing it. Is there any way to know?

[huhn]

there is a simple answer to that your screen isn't RGB so no.

[Oguignant]

Originally Posted by huhn

there is a simple answer to that your screen isn't RGB so no.

Excuse my ignorance ... you say my tv screen is not rgb?

[iSeries]

Originally Posted by Oguignant

PC mode turns off all image processing options on my TV. I think it shows the RGB signal without re-processing it. Is there any way to know?

You may find that in PC mode you are stuck with 60hz, and in any other refresh rate (like 23/24hz), the TV comes out of PC mode. It's really easy to get lost in the pursuit of absolute perfection though. What is subjective, what is objective, and what is plain placebo will always be up for debate, especially in this thread. Just try to spend some time actually enjoying some movies ��