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BootLoxes

macrumors 6502a
Original poster
Apr 15, 2019
749
897
I use the most recent apple tv with the LG C1 OLED and run an HDMI 2.1 cable between them.

During watching HDR video on both Youtube and Disney+ it will sometimes suddenly go dim for a few seconds and back. Sometimes it will just stay dim. Does anyone know how to fix this?
 

HDFan

Contributor
Jun 30, 2007
6,932
3,052
it will sometimes suddenly go dim for a few seconds and back.

Assuming the cable is certified I'd look at the LG settings. Had dimming issues with a C8 which were fixed when I restored the default settings on the LG. Some sort of auto brightness sensing issue.
 

BootLoxes

macrumors 6502a
Original poster
Apr 15, 2019
749
897
Assuming the cable is certified I'd look at the LG settings. Had dimming issues with a C8 which were fixed when I restored the default settings on the LG. Some sort of auto brightness sensing issue.

Just so I make sure we are on the same page about the dimming, its not a steady slow transition. It is an instant dim like a light switch got turned off.

The cable is the one made for the PS5 which is HDMI 2.1
 

Audit13

macrumors 604
Apr 19, 2017
6,834
1,816
Toronto, Ontario, Canada
Did you try other inputs on the TV? Deep colour is enabled on the TV?

Since your TV is capable of Dolby Vision, are you running the Apple TV in 4k SDR with match rate and range enabled?
 

BootLoxes

macrumors 6502a
Original poster
Apr 15, 2019
749
897
Did you try other inputs on the TV? Deep colour is enabled on the TV?

Since your TV is capable of Dolby Vision, are you running the Apple TV in 4k SDR with match rate and range enabled?
The format is 4K Dolby Vision and match rate and range enabled. Just checked.
 
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AL2TEACH

macrumors 65816
Feb 17, 2007
1,198
478
North Las Vegas, NV.
I have a CX and that dimming would cause a WTF moment, lol. For me, the logo luminance setting had something to do with it. I set it on high. I only noticed the dimming a few times but haven't in a while or I just became numb to it.
 

HobeSoundDarryl

macrumors G5
OP, is this problem with ONE HDR video or ALL?

Have you tried at least one more HDMI cable just to rule out that one?

Have you tried other HDMI jacks on the TV just to rule out the jack?

If you happen to have a second AppleTV (or maybe a friend could bring one over), sub it in and see if it does the same.

If you happen to have a spare TV, hook that AppleTV to it (or maybe a friend's if you don't have a spare), play the video and see if it does the same on TV#2.

Through such experiments you can narrow down if the issue is with the TV, the cable, the AppleTV, the source, etc. As you change one variable at a time, you will eventually detect where fault likely lies.
 
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