I upgraded to a not-so-bright and very shiny Sony A1E OLED 4K TV this week (from my ten-year-old Samsung). It’s basically very nice, but there’s one very, very weird effect that I’ve seen nobody mention:
This is an episode of Doctor Who paused, but it’ll do those shimmery teal pixels even when the video is running.
Like, WTF?
The only reason I’m not freaking completely out and taking the TV back to the shop is 1) it’s really heavy and 2) I’m going to an all 4K video line next week and I want to see whether that fixes this problem. I’m hoping it’s an 1080p->4K upsampling artifact of some kind.
But even so, it’s … not acceptable. So what’s up? I’ve done a full factory reset to check whether any of my settings made it go wonky, but that’s not it.
At first I thought “DEAD PIXELS”, but it’s not that, either: The shimmery pixel effect is visible all over the screen when the base colour is about what you see on the screen here. So in most scenes there are no glitches, but in some darkish, bluish scenes there are glitches all over the place.
Has anybody heard of this… thing before? Is there a setting to make it go away?
I updated the OS on the TV, and … it’s different? The teal pixel thing is less apparent, but instead there’s this:
https://youtu.be/AUlIv5Sodpg
Temporal dithering
Huh. I forgot about the first rule of debugging: It’s always the cable. Or the port.
I moved the HDMI cable from the HDMI3/ARC (audio return) port to the HDMI2 port and the problem almost completely disappeared. While it was apparent, like, a dozen scenes per Who episode in the HDMI3/ARC port, it’s only in a single scene per Who episode now.
Which makes me suspect that the real problem is just a marginal cable. I guess I’ll find out for sure next week when all the HDMI 2.0 cables and stuff arrive…
But has anybody else seen HDMI signals failing in this way before?
I have seen that kind of effect several times, and each time I traced it down to a cable. It appears to be a fairly standard response that when the phy gets an error decoding a pixel, it replaces it with that light teal color.
I found the culprit! It wasn’t the cable; it was the HDMI switch. I switched out the cheap switch with a spiffier switch, and not it no longer switches on the teal “error” pixels.
Switch.
The previous TV didn’t display any errors, but perhaps that TV did “helpful” error correction? Anyway, the display is perfect now.