Original topic:

Q90t local dimming issue when streaming hdr content

(Topic created on: 12/11/20 7:32 PM)
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Qled and Frame

I've had this issue since I bought the tv. I only notice it when I'm steaming content with hdr. The screen will randomly dim on occasion. I'd say maybe once every 15 mins (intelligent mode and eco settings are turned off). I normally keep local dimming on high when I'm watching hdr content. I'm going to start testing the standard setting. I haven't noticed this issue with sdr content. I also haven't noticed  it while playing physical 4K discs or blu rays.  Is there a fix for this? Is any one else having this issue. I've read all about the dimming bug in game mode. Unsure if it's related. I don't own any gaming consoles so I've never used game mode.

32 Replies
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Qled and Frame

My model  is qn55q90tafxza. I've done a lot of testing at this point and am still experiencing this dimming issue. I am running the latest software 1460.9. I had the issue under all prior software versions. Again this random dimming occurs when i am streaming hdr content. Sdr content appears to be unaffected as far i can tell, and I haven't noticed the issue while playing 4K blu rays with hdr. I have tested all picture modes and multiple streaming apps with 4K content. The issue occurred in all picture modes and hdr content from Netflix, amazon video, and Apple TV +. Ive experimented with the local dimming settings. When the dimming issue occurs, it is not a gradual dimming. It is very abrupt. After testing, i noticed that the abrupt dimming in brightness is almost exactly like manually switching the local dimming setting from high or standard to the low setting. But when this glitch happens, my dimming settings remain unchanged. If i have it set to high, the setting remains at high, but its as if the brightness on the screen dropped to low. I can confirm that this glitch happens if i have the local dimming set to high or standard. I tested the low setting for about 30 mins, and didn't not experience any abrupt dimming. I imagine this is because i already had the dimming set to low. This leads me to believe that the local dimming is intermittently dropping to the low setting when I'm streaming content with hdr. I have no Idea how to fix this. I imagine its an issue with the local dimming algorithm or the software. Samsung, please help

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Qled and Frame

Is there a samsung moderator that can pass this information regarding my issue along to the software development team and reply to this so i know someone has seen this?

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Qled and Frame

Samsung. Are you working on a fix for this? it's extremely frustrating. Q90t is Still randomly dimming to the low dimming setting while streaming hdr content. Can anyone from Samsung please reply to this thread. I posted this issue quite a while ago.

userxZDff1pqki
Constellation
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Qled and Frame

It is not random. It is programatic and extremely predictable. It will happen exactly 6 minutes after a mode change.

 

To "fix" it, you can toggle local dimming to low, then back to medium or high. This triggers what I am calling a "mode change".  It will look good again for exactly 6 minutes. Start a stop watch and you will see.

Switching to HDR mode also starts the 6 minute timer.

 

Common samsung, this is very easy to reproduce. Why is there no fix for this yet?

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Qled and Frame

That timing does sound about right. As far as the temporary fix, yes you're right. I kinda figured that out on my own. And you're also right that it only temporarily fixes the brightness. The reason i bought a qled is because of how bright they can get and for the full array local dimming. And i usually keep the setting at high or standard. It completely defeats the purpose of owning this if every few minutes its just going to dim down to the lowest setting. In theory, i should be able to just leave the local dimming setting at low, and crank the contrast enhancer and the midrange brightness. But i shouldn't have to do that, nor do i want to. And i have not tested that. This sudden dimming can't be an intentional part of their dimming algorithm, can it? It's extremely distracting.

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Qled and Frame

After more testing, for me, sometimes it takes a bit longer than 6 mins before it occurs. Unless I'm just not catching it every time it happens. Usually it's extremely noticeable when the sudden change in brightness occurs. But it does still inevitably happen.

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user65lH5UZoY1
Astronaut
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Qled and Frame

This same issue just popped up for me as well. I have a q90t and whether I'm watching an HDR movie or playing on my Xbox Series X in HDR the TV dims exactly 6 minutes after starting the content. I can then go into local dimming >> switch this from High to Low and then back to High again and the brightness returns - but only for an additional 6 minutes. This is absolutely ridiculous Samsung - please release a firmware fix asap! This is your flagship 4K tv! We can all reproduce the issue

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Qled and Frame

Yes. It needs to be fixed

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Qled and Frame

I've tried every troubleshooting procedure I can think of. Last of which was a factory reset of the tv. It didn't work. Local dimming still persistently dimming to the low setting when I'm streaming hdr content. There is a similar thread on this site. The user thinks that firmware update 1403 introduced this bug (which previously only affected game mode) to other aspects of the tv. For me, it still only occurs when I'm streaming shows or movies with HDR. At this point, I can only hope for a software patch. One of the main reasons, I bought this tv was the full array local dimming, and I can't even use the feature as intended. Hugely disappointing.