MadVR in use with LG OLED Thread

[nevcairiel]

That option would be rather rarely useful as you need to convince your TV thats its receiving YCbCr when everything is telling it that its receiving RGB (which very few display can even do), plus it screws up anything but madVR output, ie. Windows and player UI to boot.

[SamuriHL]

I'm confused with what you're saying. Are you saying using the ycbcr option in madvr and setting the GPU to RGB (why would anyone do that?) would cause that? Or are you saying just sending YCbCr from the GPU causes it? From what I can see, the GPU is sending YCbCr and the TV is accepting that. I think iSeries was proposing that instead of madvr outputting RGB and having the GPU convert it before sending it to the TV, that we'd have madvr output YCbCr instead. Would that not work? Is that what you're saying?

[VBB]

He's talking about this here:

Hidden Options
An empty folder or file in the madVR program directory with a specific name will trigger a hidden option, these are options you probably do not want to use.

YCbCr: Outputs YCbCr data instead of RGB, as if it was RGB.

I have not messed with that, so I can't say if it's beneficial.

[nevcairiel]

Originally Posted by SamuriHL

I think iSeries was proposing that instead of madvr outputting RGB and having the GPU convert it before sending it to the TV, that we'd have madvr output YCbCr instead. Would that not work? Is that what you're saying?

That doesn't work because the backbuffer (ie. the screen) is always in RGB. So when madVR outputs YCbCr to the backbuffer, then the GPU still thinks that its RGB, and if the GPU tries to convert it, it would screw it up - so it has to treat it like RGB.

Hence, everything thinks its handling RGB, the GPU and the screen, so you have to convince one of them that its not RGB, and thats not easily possible.

Basically, a PC is not designed for a direct YCbCr path.

[QBhd]

Originally Posted by nevcairiel

Basically, a PC is not designed for a direct YCbCr path.

That's the main reason why I settled on 8-bit RGB with the default HDMI label on the TV.

QB

[Asmodian]

Originally Posted by chros

I'm not sure that I understand what you mean, but does it matter in the end if there are pixels where they shouldn't be?

Chroma subsampling is blurring the image across the entire screen while some color fringing on the edge of a solid yellow regions or similar is a very different issue. Changing the subsampling done by the TV does not change the artifacts, they are unrelated issues, so it seems wrong to bring them up as if they were related.

Originally Posted by mark0077

Is there some calibration accuracy test that can compare this to non PC mode with the higher bit depths to see if they show a true 10 bit image with the full dynamic range that brings? Still feels wrong to have to "settle" for 8 bit when the original content is 10 bit doesn't it?

10 bit does not increase the dynamic range in anyway. I did do accuracy tests with Calman Video Pro and 10 bit does not increase accuracy at all. All it does is decrease the magnitude of the dithering noise but humans tend to perceive subtle noise as sharpness. The very slightly higher noise floor of dithered 8 bit compared to dithered 10 bit is not a significant negative, if noticeable at all. Certainly not on these LG OLEDs.

The video processing path will be different for different bit depths so various displays will handle 10 bit better or worse but the total dynamic range should never change.

[SamuriHL]

Originally Posted by nevcairiel

That doesn't work because the backbuffer (ie. the screen) is always in RGB. So when madVR outputs YCbCr to the backbuffer, then the GPU still thinks that its RGB, and if the GPU tries to convert it, it would screw it up - so it has to treat it like RGB.



Hence, everything thinks its handling RGB, the GPU and the screen, so you have to convince one of them that its not RGB, and thats not easily possible.



Basically, a PC is not designed for a direct YCbCr path.

That sadly makes sense.

Sent from my SM-G975U using Tapatalk

[chros]

Originally Posted by Asmodian

Chroma subsampling is blurring the image across the entire screen while some color fringing on the edge of a solid yellow regions or similar is a very different issue. Changing the subsampling done by the TV does not change the artifacts, they are unrelated issues, so it seems wrong to bring them up as if they were related.

I understand what you mean now, but is the end result proper 4:4:4 or not? Believe me, I'd be one of the happiest chap if it was

Originally Posted by VBB

No comments on what I posted last night? Sure, you'd have to backtrack a page, but come on!

I read it and I'm happy for you if you are happy Were you talking about SDR only and not PC mode, right?
I'm like Asmodian (probably worse, with HDR), I won't abandon PC mode
(We are busy with playing calibration, really frustrating )

[SamuriHL]

PC mode is a mess. I wanted very badly to get it to work but it's not usable imo. If you can live with the issues that's awesome. For me even with my ub820 it's a mess.

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[VBB]

Originally Posted by chros

I read it and I'm happy for you if you are happy Were you talking about SDR only and not PC mode, right?
I'm like Asmodian (probably worse, with HDR), I won't abandon PC mode
(We are busy with playing calibration, really frustrating )

I was talking about both SDR and HDR, non-PC mode. There is no way to get PC mode to be smooth. So, yeah, I'm happy, for now anyway.

I used to spend days with the meter in front of my screens, but with the C7 I've only done it a couple of times. My SDR LUT is still good, although it might be time to redo it. As far as HDR is concerned, I tried when my set was new, but I realized quickly that a LUT via DisplayCAL just wasn't possible due to the instability of the display. So I dialed in the white point and called it a day

I'll start playing with calibration again once I get a better meter and the C10 next year.

[Asmodian]

Originally Posted by chros

I understand what you mean now, but is the end result proper 4:4:4 or not?

Yes, the screen has proper 4:4:4 in PC mode.

Other pixel artifacts do not mean it is not "proper 4:4:4" it just means it has other pixel artifacts.

Originally Posted by VBB

There is no way to get PC mode to be smooth.

It is possible on the C9 but only in SDR. The behavior is different compared to my C7, and I think the C8 is like the C7.

[VBB]

That's at least some progress. Let's see how the C10 turns out. Too bad we don't have any Sony owners here. I'd like to know firsthand how those behave (the panels, not the owners)

[VBB]

Originally Posted by SamuriHL

"10 bit" is being sent as 12 bit by the GPU regardless of what it's telling you.

Just noticed that myself. Is this another Nvidia bug, or intentional? Visually, there is no difference, which makes sense now.

[leeperry]

Hey guys, about to finally jump on the OLED bandwagon and here chros claims that even latest Pana's can't do proper 24p, I also read Asmodian here in this thread saying that only C9 can do 444 24p, so if I get a 8 series I'd have to go 422 huh?

Samsung TV's 444 is not manageable because it disables BFI and most post-processing, no such thing on LG OLED?

[SamuriHL]

Originally Posted by VBB

Just noticed that myself. Is this another Nvidia bug, or intentional? Visually, there is no difference, which makes sense now.

Unsure. I just noticed it with the integral 2 and thought I'd mention it. I think nvidia has always sent 12 bit. Maybe they're padding it I'm not sure.

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[QBhd]

Originally Posted by leeperry

Hey guys, about to finally jump on the OLED bandwagon and here chros claims that even latest Pana's can't do proper 24p, I also read Asmodian here in this thread saying that only C9 can do 444 24p, so if I get a 8 series I'd have to go 422 huh?

Samsung TV's 444 is not manageable because it disables BFI and most post-processing, no such thing on LG OLED?

My LG C8 will do 23,24,25,29,30,50,59, and 60 Hz at 4k out of the box with 4:4:4 in PC mode. I don't use PC mode due to color banding.

Also, you don't want BFI (Motion Pro) on the OLED, it's terrible.

I suggest going to RTings and looking up the TV you want, it has very detailed breakdowns on just about every facet of the TV

QB

[VBB]

Originally Posted by SamuriHL

Unsure. I just noticed it with the integral 2 and thought I'd mention it. I think nvidia has always sent 12 bit. Maybe they're padding it I'm not sure.

I just did another couple of hours of testing. Turns out for 4:2:2, Nvidia sends 12-bit regardless of the chosen bit rate. Even when set to 8-bit it sends a 12-bit signal. But, what is set in the driver does make a difference. 8-bit has lots of banding, much more than with 4:4:4 or RGB. There is also a very small difference between 10 and 12-bit, with 10-bit looking ever so slightly better when judging various gradients.

It also depends on what bit rate madVR is set to. That's what makes testing this tedious. There seems to be a bug in madVR still, where sometimes, when set to 10-bit, it switches to 8-bit, and once it does that you have to reboot Windows in order to get it back into 10-bit mode. Had me question my sanity until I realized what was going on, because only when in 10-bit does 4:2:2 look the absolute smoothest out of all combos.

Went through PC mode as well again tonight. I gotta say that YCbCr 4:4:4 8-bit throughout the chain actually looks fairly decent in HDR, and pretty smooth in SDR. Add dithering back in, and perhaps a bit of "reduce banding artifacts", and it's the best choice if you can't live without PC mode.

As Asmodian pointed out earlier, things might be (slightly) different with the newer LGs, so it's always best to do your own testing.

[huhn]

Originally Posted by leeperry

Hey guys, about to finally jump on the OLED bandwagon and here chros claims that even latest Pana's can't do proper 24p, I also read Asmodian here in this thread saying that only C9 can do 444 24p, so if I get a 8 series I'd have to go 422 huh?

Samsung TV's 444 is not manageable because it disables BFI and most post-processing, no such thing on LG OLED?

no OLED can do BFI for 24p is technically impossible.

these panel run at 100 or 120 hz adn you can't BFI using a backlight because there is no backlight so you have to send real black frames.
i don't have to say more.

even if you get 4:4:4 working is far from optimal thanks to the WRGB used in these screen which can create interesting patterns...
that seems to be a bigger issue on the sony(defeat able) which supposed to have a relative good BFI and as always 4:4:4 for everything.

[Asmodian]

Originally Posted by leeperry

Samsung TV's 444 is not manageable because it disables BFI and most post-processing, no such thing on LG OLED?

LG disables almost everything in PC (444) mode.

Originally Posted by VBB

Add dithering back in, and perhaps a bit of "reduce banding artifacts", and it's the best choice if you can't live without PC mode.

Wouldn't you always have dithering on when testing? It seems weird to test with it disabled if you have it enabled for playback (of course, you always have it enabled for playback).

I have no idea how my TV looks without dithering, but if madVR dithering to 8 bit has less banding than sending the TV dithered 10 bit isn't that the better mode regardless of what it looks like with dithering disabled?

The results without dithering are very interesting when trying to understand the TV's video processing but what is important for watching is the results with dithering enabled.

[leeperry]

Originally Posted by Asmodian

LG disables almost everything in PC (444) mode.

Figures, so what does it matter whether 24p isn't smooth? If anything, it prolly is because all post-processing is disabled duh.

444 is not manageable on TV's IME due to this constraint, I'll trade full chroma for post-processing anytime.