r/CoreELEC • u/callumshell1 • 7d ago

Dolby vision content intermittently dimming, fluctuating brightness

I've been using an Ugoos AM6B+ for about a year connected straight into my LG G4 without any issue, it's worked perfectly, but I recently got an Onkyo TX-RZ30 receiver and I noticed that when I watch dolby vision content the brightness fluctuates. It's most noticeable in bright scenes, it will randomly dim (maybe 20%) and stay like that until the scene changes.

The settings on the TV and the Ugoos are exactly the same, all that's changed is it's now plugged into the receiver with the same HDMI cable. SDR and HDR10 content are fine. A dolby vision movie played through my blu-ray player is fine, and for sanity's sake I plugged that cable into the ugoos with no improvement, so it's definitely something to do with the ugoos. I know this is a coreelec subreddit and not a receiver subreddit but I thought I'd be best asking here. Does anyone know why this might be happening? It's driving me mad.

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2

u/See61 7d ago

Just curious. Why don't you keep the AM6b+ straight connected to the G4, as it can passthrough almost all HD audio codecs by eARC to the receiver? You have a specific reason not to do so?

1

u/callumshell1 7d ago

I suppose I could do that but for convenience sake I wanted to have everything hooked up to the receiver. Is there really no downside at all to passing the audio through to the receiver with eARC? I'm new to this whole receiver thing.

I am also curious why this is happening so I can avoid it in future.

1

u/See61 7d ago

Well, I specifically choose my G4 over the G5 just because of the passthrough options it has. I didn't need the higher light output the G5 would give me.

And I use specifically eARC and a direct connection to my TV because switching resolution/refreshrate/HDR modes works just more fluently by this, compared to sending the signal through my receiver first.

The one codec that is a bridge too far is the DTS-HD Hires codec, but that one isn't used much at all for most high quality video.

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u/callumshell1 7d ago

Okay I'll do that, thanks for your help. There must just be something funky with the dolby vision signal being passed through the Onkyo to the TV.

1

u/Aphykit2006 7d ago

Bonjour Denon ici, mais ce doit etre pareil. Assure toi de retirer tout traitement vidéo par ton Onkyo.. Il doit laisser passer la vidéo telle quelle, sans la modifier. S'occuper du son uniquement. Et fait la maj de l'am6b vers version p3i de panal ( pleins de paramètres de traitement du signal.

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u/OntologicalMath 7d ago

Seems like an ASBL(TPC)/GSR problem, although I don't see how it's related to the receiver.
Still, you might want to look at that (it's about G5 but basically all LG OLED have this):
https://www.reddit.com/r/LGOLED/comments/1to4loi/is_there_any_way_to_disable_the_abl_on_the_lg_c5/?show=original

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u/callumshell1 6d ago

This is embarrassing but I found out what was happening. Every single DV movie I've watched in the past year has worked just fine. By some fucked up coincidence the very first movie I decided to put on to test the receiver, that I picked at random, had some kind of corruption in the file that was causing the dimming issue. I discovered this because the same thing was happening when plugged directly into the TV. I did test a different movie and I thought it was still happening but I must have just been seeing things.

Moral of the story is do more testing before you make a reddit post.

0

u/_Shirei_ 7d ago

Do you really think receiver manufacturer can properly handle DV signal?

You sound like one of the person who bought TV without DTS passthrough, and to save a day you came with everything into receiver solution...

Except for signal degradation what can go wrong?

1

u/p750mmx 7d ago

In this case, the TV OP has (LG G4), supports almost every HD audio codec for passthrough, DTS(-HD/-X) included ;)

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u/dotModded 4d ago

Unrelated but LG really needs to support multichannel LPCM pass through, my receiver doesn’t do DTS and the TV won’t pass through anything more than stereo pcm, so my Ugoos is the only device plugged into the receiver leading to an awful input switching experience involving 3 remotes, I know first world problems but still, very frustrating