Apple TV 4K audio sync issues with enhanced player

Plex Players Streaming Devices
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[Edit: the issues below may occur only when playing back 4K content; the testing below was with 1080p content.]
Just to add to the thread, I have also had this issue. I just posted on the Plex and Apple TV Reddit forums to see if I could get any clarity around status. Interestingly, I am currently not having issues with the Plex video player on the Apple TV, either with Judder or Audio Sync. Unfortunately I am not sure if this is due to me landing upon some settings combination that avoids the issue, or whether bugs were fixed (since Iā€™ve fallen back to using Infuse as my default player most of the time).

Anyway, I wanted to share a post I just put on Reddit with settings that currently work for me perfectly - just in case it sparks some ideas for the Plex folks. I would be very interested in hearing if any of you have similar equipment (especially the LG CX OLED TV) and settings and continue to have problemsā€¦ for some reason, the settings below work for me right now.

[cut/paste forum post text below]

So to answer you I went back to check settingsā€¦ but before that, I played through a series of shows and movies to try and find the problem again. Of course, it currently does not seem to be happening so thereā€™s that.

I know Iā€™ve tried a variety of settings in the past, and Iā€™m guessing I either stumbled onto something that works, or the issue is something intermittent thatā€™s not showing right now. Issues I usually have are either juddering or audio sync - I see some folks believe that switching between the new or old video player in Plex might help one or the other problem, but not both at the same time. I canā€™t confirm that myself.

That said, the current settings I have, which I just tested, and where both judder and audio sync are good are:

Plex (Version 7.12 (22608):
Use Old Video Player is set to Off.

Apple TV:
Format: 4K Dolby Vision
Match Content: Range (only - Match Frame Rate is Off)

And just to be complete, Iā€™m running Infuse Pro 6.5.8 (3407) with no issues. This is currently connected through a Marantz SR5011 Receiver to a 2020 LG CX 77ā€ OLED TV. This hardware configuration has been consistent the entire time (including HDMI inputs through receiver).

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You are right, there are no audio sync problems when Match Frame Rate is set to Off, and this has been mentioned in this topic in the past. This is not an acceptable solution, though.

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104

Itā€™s a working workaround at least. Iā€™ve just tested it and it works for me too. I hope this will also help Plex to find the issue and fix it.

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Addition: last night, using the same hardware and settings as described above, we saw the juddering problem again (but not lip sync). Was over a longish evening of watching five different episodes of shows. There seemed to be two differences:

  1. The Apple TV Aerial screen saver kicked in several times (due to long pauses during some conversations), so I had to get rid of that to get back to Plex UI and start playing again.
  2. The last show where we saw the judder was in 4K; looking back, the earlier shows were 1080p.

I mention the screensaver just in case thereā€™s some sort of memory swapping issue going on here thatā€™s exacerbated by having to launch/stream content on top of the Plex app. That said, I think others have noticed these issues with 4K content only, so I wanted to follow up and make clear that the supposedly ā€œgoodā€ workaround settings above (Plex use old video player; Apple TV set to 4K Dolby Vision, Match Content, but not Match Framerate) are not as good as I previously reported/hoped.

TL;DR: At least the judder issue continues to be a problem on Apple TV when playing 4K content (will have to see if lip sync issue is also issue in future, but I donā€™t currently see it). Infuse continues to play the same 4K files perfectly with no judder or lip sync issues.

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Just to add to this thread, the Apple TV 4K seems to be getting worse with audio lag. All of my Plex content is 1080p mkv remuxes from blu-ray disk, and at first for me it was just with bluetooth audio that I got lag, but now itā€™s with audio through my soundbar as well.

Why are the developers so silent on this issue? A global setting in the Plex app to set the audio delay would be a good temporary fix. But for such a premium streaming box this experience is unacceptable.

And for me ā€œmatch frame rateā€ doesnā€™t fix the issue. Iā€™m starting to think the issue is with TrueHD 5.1-7.1 or certain kinds of lossless audio formats.

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Iā€™m experiencing the same audio sync issues that others have shared. Initially the issue seemed to be limited to H.265 4K HDR content, but I am now seeing regular audio sync issues with both H.265 4K and H.264 1080p content. Plex is the only app on my Apple TV where I am seeing this. Iā€™ve had to switch to the Infuse app for most media playback, as it has no such issues with the same media files. The fact that this has been a known, widespread issue for more than a year and still hasnā€™t been addressed is really unacceptable.

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Apple TV 4K Audio Lip Sync Issues
108

Iā€™ve also been experiencing this and hope this post helps narrow it down. These are constants in my tests:

tvOS 14.3
Plex 7.12 (22653)
PMS 1.21.1.3876 (2018 Mac mini running 10.15)

ATV4K Settings:
Output: 1080p SDR
Match Dynamic Range: Off
Match Frame Rate: Off
Default Audio Output: TV Speakers
Audio Format: Auto

Plex Global Settings:
Use Old Video Player: Off
Auto Adjust Quality: Off

I can reliably reproduce the below results with various files of varying resolutions and framerates, all H.264 video in my case, with some having AC3 audio and some AAC. Note that when there is an issue, audio is always behind video, though it may not immediately be off and can take up to 5 minutes to drift enough so that itā€™s noticeable (and it is a drift - I donā€™t get the people asking for an offset control since the offset is constantly changing)

WORKS

Quality: Play Original Quality
Source: Direct Play
Video: H264
Audio: AC3
Player: mpv

WORKS

Quality: Convert to 4K (Maximum)
Source: Transcode
Video: Transcode (H264 (HW) - H264 (HW))
Audio: Transcode (OPUS - OPUS)
Player: mpv

AUDIO DRIFTS BEHIND VIDEO

Quality: Convert Automatically
Source: Transcode
Video: Transcode (H264 (HW) - H264 (HW))
Audio: Transcode (AAC - AAC)
Player: AVPlayer (The EVP cannot be used when Auto Adjust Quality is enabled)

So, for me the enhanced player works when used - but Plex is not always using the enhanced player even when itā€™s enabled. Please include the above details (quality setting and what the app actually shows during playback) when posting as I think that is adding to the confusion. There may be multiple issues, but at least in my testing:

  • Video format/4K/HDR doesnā€™t matter
  • Match Frame Rate doesnā€™t matter
  • Use Old Player doesnā€™t necessarily matter since it depends on your playback quality setting!

Plex devs, what else do you need from us?

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109

I think you may have stumbled upon a related but ultimately different issue. Reason being:

As far as I know the match frame rate delay has only been reported from people with some kind of external audio source such as an AVR or soundbar.

No, the audio delay connected to match frame rate ON is a constant delay for me and I have to assume everyone else in this thread. To be exact it lags behind 3 frames in 24p content (120-130ms) in my setup.

Still, interesting find and yet another reason they should prioritize audio processing on the Apple TV.

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As far as I know the match frame rate delay has only been reported from people with some kind of external audio source such as an AVR or soundbar.

My TV actually outputs audio over optical to a miniDSP, which is basically an AVR, but it doesnā€™t matter. Thereā€™s nothing in this chain that would cause a drift so itā€™s good for reproducing the issue.

No, the audio delay connected to match frame rate ON is a constant delay for me and I have to assume everyone else in this thread. To be exact it lags behind 3 frames in 24p content (120-130ms) in my setup.

I believe you, but I only tested with Match Frame Rate Off, since that is suggested in this thread as being a fix - it is not.

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Ah I see what you mean. With match frame rate off there should be no reason to use the old player and I believe very few people do. You seem to have found an interesting fringe case. I thought it was the other way around that the old player did not support auto adjust but I must be misremembering then.

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Given that Match Frame Rate = Off is the default, the rest of my setup is very stock and the issue is incredibly easy to reproduce, I donā€™t think this is fringe at all.

I thought it was the other way around that the old player did not support auto adjust but I must be misremembering then.

This is why itā€™s extremely important that everyone adding to this thread include these details (quality setting and what the app actually shows during playback). Just setting Use Old Player = Off doesnā€™t mean the Enhanced Player is actually being used.

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113

Not sure if this can help you or anyone else with this issue, but I was messing around with the Apple TV 4K audio/video settings and changed the HDMI Output from YpBcr to RGB High and for 24fps content that Iā€™ve tried so far no audio sync issues.

However when playing 50fps content the audio is terribly out of sync.

I will keep looking for setting combinations to find a solution but again, THIS ONLY HAPPENS IN THE PLEX APP! Developers Iā€™m sure everyone would at the very least appreciate some kind of response on this issue. Apple TV + and Disney + donā€™t have any of these issues.

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Just to add to the list, I have had this lip sync issues for years when Match Frame Rate is enabled. This is on the Apple TV 4th gen (non-4K) version. I would love to see a solution.

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I thought Iā€™d chime in to add another affected user. My setup works flawlessly with all apps but Plex. Content mostly affected is 4K HDR, match frame rate on with any lossless audio. If I change the audio to DD5.1 it improves slightly but still an issue. Like others if I switch match frame rate off the issue is hard to notice if even there.

Infuse - Plays everything from Plex with no issues.
Netflix - No issues
Apple TV+ - No issues
HBO - No issues

Also I run the Plex app on an Nvidia Shield with no issues.

I cancelled my Plex Pass subscription because of this issue. Decided to fund Infuse until itā€™s fixed.

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116

Just switched back to the webOS Plex client and canā€™t believe how nice it is to have synced audio.

The interface sucks compared to the Apple TV but at least it works for its main purpose.

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117

Is there ANYTHING I can provide here to move this along? Logs, videosā€¦anything? The issue impacts any content in x265 for me, not just 4K.

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118

Just tag @elan and make fun of plex amp. Thatā€™s the only way he makes appearances in other threads that are not plex amp.

Maybe that will nudge his attention for a bit and tell someone to actually work on it.

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Itā€™s at least reassuring that everyone else has this problem too. Iā€™m so tired of audio sync problems. Itā€™s 2021, there shouldnā€™t be issues like this today. I had a DLP projection tv many many years ago and it was impossible to get the audio sync correct. I was so happy when it died but ever since then Im super susceptible to noticing sync problems. The rest of my family doesnā€™t notice and Iā€™m like HOW CAN YOU ALL NOT SEE HOW OUT OF SYNC IT IS?!

Dropping $200 on a shield to save the frustration of dealing with this is looking like a good option.

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120

Itā€™s quite clear this topic is being ignored. Is there no other way of filing a bug report? GitHub?

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121

Appears this may have be more of an Apple issue than a Plex issue, to which we will be getting a fix soon.