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Author Topic: OLED 83" 2021 PC mode artifact  (Read 1258 times)

TheShoe

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OLED 83" 2021 PC mode artifact
« on: March 24, 2022, 03:46:15 pm »

Sharing in case others see this:

I am running my new LG OLED 83" @ 4K120Hz, with the input configured on the OLED as "PC".  The video card is an nVidia 3090.

In the nVidia control panel when running "PC->3840x2160->120Hz, you will see tearing in video - particularly 4K video.  Akin to a VSYNC issue.  This is even though JRVR reports the output as 4K23.997 and the TV seems to think so as well.

If you change the resolution in the nVidia control panel to "3840x2160->60Hz (Native)", then there is no tearing on playback.

It seems the "PC" mode in the driver regardless of whether the LG OLED input is set to "PC" or "Home Theater" mode is the root cause.

Thankfully it's not a big deal to change the settings in the control panel as my HTPC is dual use: Gaming and Home Theater.  So far I can't find any upstream settings in the OLED TV or the Marantz PrePro that resolve this.

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TV: LG OLED C1 83"
3D: LG OLED C6 65" (two) - madVR MVC->SBS
3D: Valve Index (using Media Center+MadVR) + Virtual Home Theater (Steam)
HTPC: Core i7, Win11, nVidia 3090RTX
Storage: 500TB Snapraid via SMB to Ubuntu 18 LTS server
Audio: exaSound e68 Multichannel USB DAC, Sonus Faber Speakers, REL Subx2
Video: HDMI 2.1/4K@120Hz, JRVR (2D), MadVR (3D), 7.1 Channel Audio into AMPs: Conrad Johnson 2/5 Channel Amps, Marantz av8805A PreAmp
Cables: Shotgun Interconnects, AudioQuest Cinnamon 48GB HDMI cables

jmone

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Re: OLED 83" 2021 PC mode artifact
« Reply #1 on: March 24, 2022, 04:21:14 pm »

I seem to remember Hendrik saying that when playing (say 23.976) @ higher frame rates (say 120hz) that JRVR will then output 5 of the same frames.  I wish I had some 2.1 HDMI equipment to test :( but what happens if you use MC's Display Rate changer to dynamically set the playback chain HZ to match the fps (eg so everything is 23.976 hz)?
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BryanC

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Re: OLED 83" 2021 PC mode artifact
« Reply #2 on: March 25, 2022, 08:26:35 am »

In addition to display rate switching, check out your black frame insertion settings on the TV if using a non-native fps. There are different names for this technology, I think LG calls it Motion 240.
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TheShoe

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Re: OLED 83" 2021 PC mode artifact
« Reply #3 on: March 25, 2022, 10:28:50 am »

@jmone - yes I did set the custom display refresh rate to match the video, but no effect.  wonder what happens if I disable it altogether, so MC does not attempt to adjust at all....

I can try disabling any of the features of this set that affect frame interpolation (I tend to run that on very low, just enough to smooth out judder in panning).  There's also this "FILMMAKER MODE" I can play around with.

At least at this point though - leaving the TV settings as-is, simply changing the nVidia driver from it's PC resolution/refresh rate settings to the UltraHD/HD/SD complement of resolution/refresh rate resolves the issue.

thanks both for suggestions!
Logged
TV: LG OLED C1 83"
3D: LG OLED C6 65" (two) - madVR MVC->SBS
3D: Valve Index (using Media Center+MadVR) + Virtual Home Theater (Steam)
HTPC: Core i7, Win11, nVidia 3090RTX
Storage: 500TB Snapraid via SMB to Ubuntu 18 LTS server
Audio: exaSound e68 Multichannel USB DAC, Sonus Faber Speakers, REL Subx2
Video: HDMI 2.1/4K@120Hz, JRVR (2D), MadVR (3D), 7.1 Channel Audio into AMPs: Conrad Johnson 2/5 Channel Amps, Marantz av8805A PreAmp
Cables: Shotgun Interconnects, AudioQuest Cinnamon 48GB HDMI cables
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