55GZ950 giving up on me or is it something else? Flickering in dark scenes when living room is dark

Geert81

Novice Member
First, thank you for reading this and possibly helping me out! I appreciate it!

Let me start by saying I love Panasonic. Had a 50 inch plasma for 10 years and then finally switched to the 4K 55GZ950E last summer, after trying the 65GZ1500 but that made me nauseous and car sick. Too big. The 55 inch was amazing. In every possible way.
Until this week.

At night, when the living room was dark, certain movie and series scenes started to cause flickering when it was dark. Two days in a row. For example between two scenes when the screen goes to black for a couple of seconds, it got lightly, large, flashing areas on different parts of the screen (exhibit 1), then another scene where a house was filmed at night, the skies above it (dark with some clouds) gave the same flashing. As if the aliens were about to land. But they weren't. This show wasn't about aliens. It looked like watching a screen with a bad and slow refresh rate, but only in dark/grey areas. Pure blacks are fine. Then another scary movie scene in the car, where the darkened ceiling started to flash and flicker a bit as well. Pausing the movie/show made it stop.

When I turn on lights in the living room, it's much less noticeable.

Here's what I tried to fix this. My apple TV (4K) goes to a 4K receiver and then to my tv. Plugging the Apple TV directly into the tv didn't fix it. I watch in THX cinema or THX cinema bright, with all help turned off (so the standard settings). But switching to the other picture modes didn't help. Changing the output of the apple TV to Dolby Atmos didn't fix it either. Switching HDMI ports didn't help either. This time, in some of the scenes, pausing them no longer helped. The flickering continued. Only on the dark but not black area's that are not moving.

Then I decided to switch my Apple tv to the other 65 1500 Panasonic I still own but rarely use. No problems there.
Back to the 55. Same problem.

Then, and bear with me please, after some switching back and forth, trying different HDMI ports and screen settings. Suddenly the issue seems gone. I, at the moment, only get it in the scary movie car scene when the picture is on dynamic. The other modes are fine. I can no longer reproduce it.

Now back to exhibit 1. Now that the problem seems gone, if I pause that dark intermezzo between scenes, I see some squares on the screen. Light purple. You know, because this show wasn't shot in 4K and is from 2010 or something, the squares you get when you watch something with a lower quality (it's streamed through my 4K apple tv). It seems as if, when the issue was present, the TV was trying to fix it or something and was freaking out, was refreshing those areas continuously. Yet, mpeg remastering and well all enhancements were always turned off.

I cancelled the repair guy that was going to come tomorrow, since I can only create this at night when it's dark. It's invisible when there's daylight.

What does this sound like to you? I don't think it's apple TV (I hadn't changed any settings there, I did now, but that didn't fix it). It's not my receiver because bypassing it didn't help. I'm not sure why it's gone now. And where it came from. I had the problem two nights in a row just before today. It may, of course, return.
 

mikej

Well-known Member
It's difficult to say whether there is an actual fault with the TV without photos, but one thing that is for sure is that a TV like a Panasonic GZ can really show up any deficiencies in poor quality sources or source material. Streaming services in particular can be quite varied in their output - even content steamed in HD can be such a low bitrate that the picture quality can suffer.

Near black / dark grey scenes can be problematic for OLEDs sometimes. I mostly watch TV in the evenings and use the Pro 2 picture mode which is one of the darker ones and may mask issues like this slightly. The bright room THX cinema mode is quite bright and may make your issue more obvious. I'm not sure why the time of day makes a difference though - do you have the TV's ambient light sensor on ? I have this turned off as I prefer to make any changes to the picture myself, rather than relying on the TV.

Personally, I've had no picture issues when streaming good quality 4K content from Netflix or Prime but have occasionally noticed pixelation in dark scenes when watching some of the Freeview Play catch-up services in HD. I put this down to issues related to streaming because, on at least one occasion, I was able to test the quality of the stream vs a PVR recording, which didn't show any problems.

Are you happy that your broadband connection and WiFi speeds are sufficient for streaming in 4K ? Hardwiring the Apple TV to the router would be preferable to relying on Wi-Fi, IMO.

Do you have a Blu-ray player to help with the troubleshooting ? I would also check the HDMI connection between Apple TV and your TV - swap the cable with another if you can.
 
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Geert81

Novice Member
Thank you for your feedback. Those are good points. What I meant is as soon as there is ambient light, the screen is lit a bit from the outside light source and then you notice it less (because the scenes are dark). But it's still there just as much, just less visible.

But last night, everything was suddenly gone. Even in the same scenes. I could no longer reproduce it. What was interesting then is that those very same dark spots now show some light purple rectangles that you can almost not see (because the image isn't fully perfect indeed and it shows in those areas, a bit of black/purple pixelation). Now he just leaves them, they don't move nor change. It looked like as if he was trying to fix those rapidly and freaking out about it the two days before. So someone, either apple TV or the TV's processor, was trying to do something with those areas before. If I now pause those scenes and only at that very moment, there sometimes is one flicker in those exact same areas, as if he makes a decision on how to show it, how light/dark it should be. But then it stops.

My phone couldn't capture the flickering. Only my eye saw it, especially while not looking directly at it (as if it's refresh rate related too).

Good idea when it comes to blu-ray. I'll try those same scenes on Blu-ray if it comes back again.
 

Waynej

Distinguished Member
Flickering may be a result of the ambient light sensor which tries to fine tune the image based on room lighting. I’d have this turned off anyway, as well as disabling dynamic contrast.

Professional and THX picture modes are a
good starting point. The only things you should really need to tinker with is your SDR luminance and whether you prefer Intelligent Frame Creation off or on min. It’s personal preference for most people.

Establish whether you see these flickering issues with the TV’s internal apps, this will help you determine whether the issue is either a fault, settings related, or potentially an external device.
 

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