madVR - high quality video renderer (GPU assisted)

[SamuriHL]

Hey all, I have what I hope is a simple question. I'm now on a 4K LG OLED and I have the gamma set to BT.2020. What should I set for gamma in madvr to match that? I know this is total newbie land here but I'm still learning about the 4K world. Thanks!!!

[huhn]

bt 2020 is not a gamma curve it is a colorspace a "gamut".
no screen can show it not even professional ones.

if you don't have calibration equipment leave it at default.even if you select something like DCI P3 which is nearly doable on these screen you wll not get DCI P3.

[SamuriHL]

That's what I get for doing things from memory and not looking. You are correct, that's colorspace.

Gamma: BT.1886

That is what I meant to say.

[wnholt01]

This isn't a madVR problem specifically I think, but I encounter it when using madVR with resolution switching. Anyone else use RGB 12 bit for 4K 23.976 with Nvidia card and have a problem getting the 12 bit to stick. Works fine if I leave in 23.976, but when switching between 23.976 and other refresh rates like 60 every once in awhile RGB for 4K 23.976 switches back to 8 bit, which of course screws up HDR until manually toggling back to 12 bit.

[Asmodian]

Yes, this is a known issue with current Nvidia drivers.

Try 382.53 or 385.28.

edit: It doesn't have to mess up HDR though, my LG OLED (C7) handles 8 bit HDR even better than 10 bit HDR (less banding, madVR's dithering is better than the TVs - or something).

[SamuriHL]

I'm seeing the same with 8bit on my C8. Working very well with HDR.

[huhn]

Originally Posted by SamuriHL

That's what I get for doing things from memory and not looking. You are correct, that's colorspace.

Gamma: BT.1886

That is what I meant to say.

that't a gamma choicen on the black level of a display a oled should respond with a 2.4 gamma in that setting but they obviously don't do that.

but no matter what you change as a gamma setting there is nothing to change in madVR.

[wnholt01]

Originally Posted by Asmodian

Yes, this is a known issue with current Nvidia drivers.

Try 382.53 or 385.28.

edit: It doesn't have to mess up HDR though, my LG OLED (C7) handles 8 bit HDR even better than 10 bit HDR (less banding, madVR's dithering is better than the TVs - or something).

Thanks. I know 8 bit HDR is technically supported but I thought it wasn't recommended. For some reason image goes mostly pink when sending RGB 8 bit HDR to my JVC projector. Good to know it isn't caused by a limitation of 8 bit HDR.

[Asmodian]

Yes, I think that is due to the projector not handling it correctly, because all HDR capable hardware players output 10+ bits, rather than a limitation of HDR itself. You do need good dithering to avoid banding with 8 bit HDR content, something that does not live through compression (like the HEVC on a UHD bluray) but does for madVR's output or video games.

Originally Posted by huhn

that't a gamma choicen on the black level of a display a oled should respond with a 2.4 gamma in that setting but they obviously don't do that.

Interestingly I do not measure a notable difference between my LG C7's 2.4 and BT.1886 settings, but they are not exactly pure power 2.4 near black either (it actually rises slower, I think to make shadows look very deep). The 2.2 setting is pretty close to 2.2 though.

[SamuriHL]

Originally Posted by huhn

that't a gamma choicen on the black level of a display a oled should respond with a 2.4 gamma in that setting but they obviously don't do that.

but no matter what you change as a gamma setting there is nothing to change in madVR.

Good to know thanks. Like I said I'm still learning on this 4k stuff so I'll probably ask a bunch of stupid questions while I get it dialed in. Thanks for your patience!

Sent from my Pixel XL using Tapatalk

[Manni]

Originally Posted by wnholt01

Thanks. I know 8 bit HDR is technically supported but I thought it wasn't recommended. For some reason image goes mostly pink when sending RGB 8 bit HDR to my JVC projector. Good to know it isn't caused by a limitation of 8 bit HDR.

It's not caused by a limitation of 8bits HDR, it's a bug in the JVCs.

The only thing you need to do to get the JVC to work with HDR 8bits, as reported a few times, is to disable "Send HDR Metadata" if using passthrough, or use the HDR to SDR conversion wiht Pixel Shader.

The magenta bug in the JVCs is far worse with recent nVidia drivers. It's only at 4K60p with 385.28 while it's all 8bits modes with the more recent ones. So it could be nVidia rather than JVC.

[madFloyd]

I'm trying to optimize madVR playback to avoid dropped and repeated frames. I *think* this boils down to subjects:

1) are there any obvious background processes that one should disable for a dedicated HTPC? I can't be sure that this is part of the problem, but I'm guessing it certainly wouldn't hurt.

2) My HTPC desktop runs at 3840x2160 23.979 (nVidia 1060 driver v385.28, running Kodi DSPlayer) so I don't have to change resolution (and experience HDMI handshake with my JVC projector) when playing movies.

I cannot get it to run at 23.976. I've tried custom resolutions specifying 23.976 to no avail. I've been told that only Intel graphic cards will do 23.976. If this is true, I will have to live with a frame repeat every so often and so be it, but can someone confirm?

Thanks in advance.

[huhn]

1. shouldn't affect repeated dropped frames.

2. read this: http://madvr.com/crt/CustomResTutorial.html
getting 23.976 is not the point of this.

[Asmodian]

I get a very nice ~1 day between drops/repeats estimated (with no drops/repeats during playback) with an Nvidia GPU, drivers 398.36, Windows 10, and a custom resolution (added and tuned by madVR) for my LG C7. It is possible on something besides Intel.

[Redemption80]

As someone who has spend about a decade being annoyed by this (eventually giving up and speeding things up to 24fps for about 4-5 years) my main advice would be do not overthink it, and use your eyes as the judge, not an OSD reporting frame drops/repeats.
Driver 390.70 and an optimised custom res was what i stuck with for most of 2018, a nice little custom res that only dropped a frame every couple of days,but every driver after that the sane custom res (Created within MadVR) would fail.

Recently Nvidia fixed their drivers and 398.36 has proper 23.976 support after years of 23.970, and from a few weeks of testing i think its great. OSD did trigger my OCD with the reported drop every 12-13mins, but i can't see it and i have really looked

Browsing this thread, i've saw that JVC projecters and newer Nvidia drivers may have issues so that may not be an option, but 385.28 should be good if you let MadVR optimise for 30-60mins and afterwards you have a good selection of custom resolutions to test.

Again, as someone who used to get overly techincal but has fallen behind with old age, my main advice would have minimal exposure to any OSD or stats.

[Q-the-STORM]

Originally Posted by Asmodian

I get a very nice ~1 day between drops/repeats estimated (with no drops/repeats during playback) with an Nvidia GPU, drivers 398.36, Windows 10, and a custom resolution

8 bit or 10/12 bit?

I just updated to 398.36 to see if it works with my 1080ti, but when I create a custom resolution it always switches to 8 bit.

[Asmodian]

8 bit, my TV works better with 8 bit input anyway but it is a limitation of custom modes with current drivers.

[ryrynz]

Has anyone documented the various issues with their latest drivers and actually reported them? I don't get why theses issues are still around almost a year after they surfaced.

[Manni]

Originally Posted by Redemption80

Browsing this thread, i've saw that JVC projecters and newer Nvidia drivers may have issues so that may not be an option, but 385.28 should be good if you let MadVR optimise for 30-60mins and afterwards you have a good selection of custom resolutions to test.

There is no need to run the 30-60mn optimize with the JVC, none of the options work except the default EDID/CTA, which gives one hour or so without a frame drop/repeat in 4K23p and about a day at 1080p (with 385.28).

Originally Posted by ryrynz

Has anyone documented the various issues with their latest drivers and actually reported them? I don't get why theses issues are still around almost a year after they surfaced.

Has anyone ever had success reporting any bug to nVidia? I've never got any reply or seen any improvement, so I haven't bothered with the recent bugs, as it looks like many of them are JVC specific, so they couldn't care less as they wouldn't be able to reproduce.

Here is my recap (I've given up trying new drivers, I'll try one when someone with a JVC reports that a new driver works fine). Note that this is with the rig described in my sig, testing 4K23p RGB 12bits 4:4:4 for all 23p HD and UHD 2D content, 4K50/60p RGB 8bits 4:4:4 for all 50/60p content and 1080p23FP for 3D Mkvs. I have no idea what results others get.

https://imgur.com/a/xekcsZ6

[madFloyd]

Originally Posted by huhn

1. shouldn't affect repeated dropped frames.

2. read this: http://madvr.com/crt/CustomResTutorial.html
getting 23.976 is not the point of this.

Thank you! Fascinating stuff.