Audio sync suddenly off (ATV4K App, Onky rcvr, MacOS server)

Plex Players
1

A few weeks ago the audio sync suddenly became an issue. Always been fine until then. I read in other posts that enabling the enhanced player could cause this, but my Plex app on my ATV4K does not have the enhance player option in the settings.

Note that the sync is fine when watching through the LG TV Plex App, but there are issues with sound using the ARC (DTS doesn’t work for example) so I’m limited to the TV audio when using the TV Plex app. As you can imagine I’d really prefer not to have to limit myself.

Any clue how to fix the sync on my ATV4K/Plex app?

Thanks

2

Can’t help with the ATV. Regarding the LG:

If the LG does not support DTS audio (2020 & newer models), Plex Media Server should transcode it to a supported format then pass it to the Onkyo via HDMI-ARC. Make sure that DTS is not selected in the LG Plex app audio settings.

If the LG does support DTS audio, it will be passed via HDMI-ARC to the receiver. With DTS-HD, only the lossy core channels are passed.

TrueHD audio will always be transcoded, as it is not supported by the TV.

Note that if the media is direct streaming, such as when audio is transcoding, enabling subtitles of any format results in a video transcode.

3

First, I found that none of the DTS-ish formats send sound to the back channels (my setup is 5.1) via ARC. Not using the receiver is a not starter because without it I have to use the TV speakers…not happening. So I use the ATV exclusively…well, I did until the audio non-sync issue started…

Second, the audio sync was the point of the question…but I appreciate your taking the time to respond. Thanks.

4

I think this is an issue with something in the latest ATV update (TvOS 16), and is seemingly highly inconsistent and hard to reproduce. I am having this issue with 2 different AppleTV 4K units (1st and 2nd gen).

The issue seems to be with any app that does not use the default built in media player (i.e., Plex, Infuse et al.). The developers over at Infuse have also noticed this, and james’ comment from a month ago suggests they’re working on something to get this resolved with Apple.

5

It’s happening on my Apple TV HD as well. I used the VLC app on my Apple TV to connect to plex and wouldn’t you know it…. Audio sync issue is gone. I’ll just keep using VLC until plex decides to fix this. So probably some time in 2024.

6

Curious, how does one connect VLC to your media?

7

There is a UpNP play option on the vlc app which shows my plex server, just select that.

8

I’ve also given up on the Apple TV app for the time being because of audio sync issues and went back to the LG WebOS player.

Both going through a Yamaha RX-A4A and only the Apple TV has problems (and then only the Plex app - Netflix etc on the ATV are fine).

Apple TV 4K 2022 and tvOS 16.2

9

Problem is that much of my content is DTS and DTS won’t pass through the ARC connection to the receiver.

Very annoying. Crazy that Plex is always adding marginal features but ignores bugs and other highly desired features.

10

Prior to trying the ATV app, I was using the LG WebOS app exclusively for years. I can’t say I noticed any issues with DTS transcoding. I believe it is passed through ARC. Which TV are you using? OLED65C8 (2018 model) here.

Either way, it’s annoying. The main reason you’d use an ATV is to get around limitations of the built-in apps.

11

Maybe your receiver has eARC like the TV…mine does not, only ARC and ARC doesn’t pass 5.1 DTS. That’s when I bought the ATV4K. It was perfect until this started.

12

Which LG TV do you have?

Which Onkyo receiver?

HDMI-ARC passes AC3, EAC3 (including Atmos), DTS, and PCM up to 5.1 channels.

HDMI-eARC will also pass DTS-HD, DTS:X, TrueHD, & TrueHD + Atmos.

I’ve an LG B7 connected to a Denon receiver via HDMI-ARC. The Plex app passes DTS audio to the receiver. For DTS-HD, it passes the DTS lossy core, dropping the -HD portion of the audio.

13

I’m not using ARC/eARC, but experiencing the same “audio out of sync” issue with 4K HDR content since the upgrade.

14

You are correct (I misspoke…it was the DTS-HD that I couldn’t pass) and I have a lot of Bluray content that came with DTS-HD that was annoying not passed.

15

I have recently discovered that the plex app doesn’t send DTS… why/when can we get that fixed? Infuse wants $100 to support it. Good opportunity for Plex to give it away and get more eyeballs!!

16

@dmarr

If you are referring to the AppleTV, Apple does not permit any app to pass DTS or TrueHD audio.

It is instead passed as PCM.

The conversion to PCM is lossless, so there is no drop in quality.

However, the Atmos portion of TrueHD + Atmos and the “:X” portion of DTS:X is lost in the process.

17

Indeed the AppleTV; thank you for the clarity @FordGuy61. I see my receiver picks it up as PCM, but the signal is obviously different, as the DTS light doesn’t fire up.

The conversion to PCM is lossless, so there is no drop in quality.

Will the receiver handle the converted signal any differently? Should be exploring options for devices that would passthrough DTS, or would there be no difference?

18

If the receiver handles multi-channel PCM then there is no difference.

19

I’m not sure how to tell. It has an optical in, that I have connected to an HDMI switcher. There are options on the switcher like passthrough and 5.1. If I set to 5.1 the receiver picks up the Dolby Digital, and if I use passthrough, the receiver just says “PCM” and uses Pro Logic II.

20

Optical audio supports Dolby Digital and DTS up to 5.1 channels and PCM up to 2.0 channels.

Given your equipment, when you play DTS audio it could be limited to 2.0 channels (Apple TV sends DTS as PCM, which is limited to 2.0 by optical connection).