tvos 14.5 audio synch (computers/itune server)

Since moving to TVOS 14.5 and a TV 4k I am having audio issues with some of my itunes server video files (so through the "computers" app). I still haven't pegged exactly what is causing the issues. I've tried every single possible audio setting on the TV (auto, stereo, 5.1. 16 bit vs auto, loudness reduction vs not, etc.). Including moving the one Apple TV to a different physical TV to check it. Still the issues (I have not tried using optical output yet though, but I will be soon).


All impacted files seem to be HEVC, but the vast majority of HEVC movies and TV shows I have on my iTunes server are NOT impacted. All files, but impacted and not use AAC audio. Some stereo, some 5.1. A couple files impacted had audio 5.1 and between 192 and 384kbps encoded. Some that are stereo and 128kbps and 5.1 128kbps are also impacted.


What is happening is the audio is falling out of synch and relatively quickly. Some are faster than others and you can notice the audio is out of synch within just a minute of watching and 3-5 minutes in the audio is a good 3-4 seconds ahead of the video. Some take 2-3 minutes before you can start to notice and might only be a second or so ahead of the video by 3-5 minutes.


All of them the audio cuts out completely after watching for around 7-10 minutes.


Pausing the video and resuming doesn't fix it. Scrubing/faster forward or backward a small amount fixes the audio synch, but it falls out of synch faster usually. It also fixes the no audio, but it cuts out in just a minute or two then if it had already stopped.


If you exit to the menu and then resume the video it is completely fixed. Until it falls out of synch again in a minute and gets progressively worse.


Also of note, some of the videos the audio also has quiets popping sounds in it, but not all effected videos.


I haven't tracked down one of my older H.264 encoded videos yet to see if they are impacted (almost all AAC higher bit rate stereo encoded).


Some of the stereo AAC sources that were impacted, I did a quick recode for file and changed the audio source to AAC 5.1, no change to bit rate and it works fine. Some of the 5.1 impacted files I've tried re-encoding the audio to 128Kbps AAC 5.1 and they are still impacted. Sometimes re-encoding it a couple of times and magically it works. I've been playing with trying AAC (FDK) (my default for everything) and AAC (lav). I haven't noticed yet if there is a pattern, but I think AAC (lav) is more often working.


To be clear, my other two Apple TV 4k are on TVOS14.4 and do NOT have this issue. Nor have any had this issue on any previous TVOS versions for any of these files.


I'd really rather not have to go through my entire library of ~600 or so movies and 30 odd TV shows I've ripped from blu-rays to try to figure out which ones are broken and which ones aren't and try to re-encode the audio until I can get it to work. For now the "broken" Apple TV got moved to the room where that TV is only used for Netflix and Disney+ (no streaming service seems impacted).


Any help would be greatly appreciated! I am honestly intensely frustrated with the entire TVOS 14 track with all of the audio issues Apple has had. Somewhere around 14.1 or 14.2 they broke 5.1 sound in Computer (iTunes server streaming) where you HAD to set the audio output to stereo. If you had it on auto for a 5.1 source or just set to 5.1 playback wouldn't work flat out. The video would freeze trying to load. Occasionally I could get it to work by scrubbing in to the video a little, but 9 out of 10 times it was just broken. Resuming an already started video worked, but anything from the beginning was just broken. They DID finally fix that with 14.5. But now this with the broken audio synch in certain videos (and no clue which ones!!!! At least if I could identify anything in common I could track down which files I might need to re-encode).

Posted on Apr 28, 2021 4:41 AM

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Posted on Apr 28, 2021 5:50 AM

Oh an update. Apparently re-encoding the audio isn't working on any of the files that are broken. They just seemed to work better. Watching longer and the audio still drops out of synch and then breaks entirely. Also checking a bit more thoroughly with other video files, it is all HEVC files the audio synch is broken in Computer app/streaming from my iTunes server. Doesn't matter the audio type, video frame rate (23.9..., 24, 30, 60fps) and resolution (720, 1080 and 4k all impacted).


Haven't checked h.264.


So in general it is completely unworkable in TVOS14.5. Thanks Apple.


Maybe it is unique to my one specific AppleTV 4k, but I am not willing to try updating my others to see if they'll also break. I did try resetting the AppleTV and still broken. With this and the broken 5.1 sound in earlier versions of TVOS 14 in the Computer app, I have to wonder how much testing Apple actually does? There are several varieties and methods used to create the HEVC files in question, so it seems all HEVC files are broken streaming from an iTunes server :-(

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Apr 28, 2021 5:50 AM in response to azazel1024

Oh an update. Apparently re-encoding the audio isn't working on any of the files that are broken. They just seemed to work better. Watching longer and the audio still drops out of synch and then breaks entirely. Also checking a bit more thoroughly with other video files, it is all HEVC files the audio synch is broken in Computer app/streaming from my iTunes server. Doesn't matter the audio type, video frame rate (23.9..., 24, 30, 60fps) and resolution (720, 1080 and 4k all impacted).


Haven't checked h.264.


So in general it is completely unworkable in TVOS14.5. Thanks Apple.


Maybe it is unique to my one specific AppleTV 4k, but I am not willing to try updating my others to see if they'll also break. I did try resetting the AppleTV and still broken. With this and the broken 5.1 sound in earlier versions of TVOS 14 in the Computer app, I have to wonder how much testing Apple actually does? There are several varieties and methods used to create the HEVC files in question, so it seems all HEVC files are broken streaming from an iTunes server :-(

May 2, 2021 10:51 PM in response to Joseph Delaney

So I have done some additional tests on my setup here and have found that for my collection it is specific to the files that are using AAC audio encoding. (Which is most of them). I have some that I encoded with AC3 and have not had issues with those. I noticed last night that on some of my AAC files I also get popping noises coming through randomly while the file plays as it slowly moves out of sync with the video. I used avidemux to reencode the audio tracks to AC3 on a couple affected files and they played perfectly after that. I am not willing to have to do that to my entire collection for Apple’s screw up though. My guess is that the AC3 works because it is just doing a pass through. Apple seems to be trying to do something different with other audio formats. I called Apple support about this issue because I wanted Apple to know they had messed up my device. I went through the whole device reset twice to satisfy first level support. They basically had no idea and have me taking my device into a repair shop today. If it helps Apple figure out what has gone wrong with their update it will be worth it. At least it is still under warranty so I shouldn’t have repair costs. Maybe they have a way to revert it back to 14.4 for me.

Apr 28, 2021 3:59 PM in response to azazel1024

I am experiencing exactly the same issues when watching content streaming from my iMac to my AppleTV 4K: audio falling out of sync, and dropping out altogether. This is with h264 files that all played fine on TVOS 14.4 (I'm halfway through a TV series that was good on Monday, and stuffed on Tuesday after the TVOS 14.5 update, and now unwatchable under TVOS 14.5.)

I've tried all combinations and permutations of settings, resets to factory defaults etc., but to no avail.


I ended up swapping out the ATV 4K for an older one still running TVOS 14.2 and all is working as expected. I did turn off automatic update on this ATV, so as not to kill it too!

Apr 30, 2021 4:52 AM in response to azazel1024

You can turn off the automatic updates - it's not quite "downgrading" but it does give you the option of waiting until you hear if other people have problems, or until there's a "dot-one" bug fix release (those usually come out pretty quickly, I would not be suprised if we see 14.51 come out in a week or two).


Back to the issue - I turned off the match frame rate setting, and it seems to have helped (can't be 100% sure without watching more - but last night I didn't see any audio sync issues).


I noticed the same sluggishness in menus while experiencing the sync issues. I also noticed that the video would sometimes black out for a second or two at certain times (resuming after the screensaver, or on initially playing) - and those black-outs don't happen when the frame rate setting is turned off. I think the black-out is related to my particular setup and how my TV responds to the frame rate switching (so other people may not experience the same thing), but it never used to happen before Monday's update so definitely something changed in tvOS - the frame rate switching seems to be kicking in for TV shows, when it isn't needed.

May 6, 2021 12:05 AM in response to azazel1024

I submitted feedback as well. The Apple repair shop ended up just replacing my device with a new one. Luckily the new one has 14.4 still installed. The prompts to upgrade are really annoying though. Seems like every time I pause what I am watching I get prompted to upgrade. I just have to make sure I am really careful not to take the "default" option to turn on automatic updates.


I missed the window to downgrade my iPad and my iPhone though. Both of those devices are still having audio problems. I haven't tried 14.5.1 yet but I have heard others saying that it does not have a fix.


I really hope that Apple can get this issue fixed soon.

Apr 29, 2021 8:06 AM in response to azazel1024

I am seeing this issue when streaming my content from a Synology NAS. It basically has rendered my entire collection unwatchable. All of my media is in H.264 encoding. I haven't taken the time to figure out if all audio formats are affected but it seems to affect most of the videos I have tried to watch. Apple needs to fix this asap. I wish there was a way for me to revert back to the previous version. I'm stuck until Apple comes out with an update.

Apr 30, 2021 3:59 PM in response to azazel1024

I have this problem too. I have 2 4k AppleTVs and an HD will be downgrading the HD asap. However I have noticed it is not just affecting the apply TV the quiet pops or crackles also affect home sharing to iPads on 14.5 and also my MacBook Pro running Big Sur 11.3 not only that is copying the film with the crackles to the MacBook Pro and the crackles still exists on playback.

Apr 29, 2021 4:29 AM in response to Joseph Delaney

Yeah I haven't even tried it yet :-(


I still haven't seen it in streaming, though I think I (well, mostly my kids) have been streaming netflix on the 14.5 TV and that isn't impacted. I'll try some other streaming apps later. Well, I guess it makes me feel slightly better I am not the only one. Which I hope means Apple will become aware and fix it promptly (and I can't help asking though, how the heck didn't they catch this? Or was it some final bug fix that broke it from beta 14.5 to full release that wasn't fully regression tested?)


One other thing I've noticed, returning the to the menu from a video is also slow. It almost always reacts to the button input on the remote, but it is about a 5-6 second lag. It isn't always, but it is often that I see that lag. Just when video is out of synch it seems. No other functions seem to be lagging. Just that.

Apr 30, 2021 4:31 AM in response to RavenDiaval

Your last is one of my biggest issues with Apple. I get why they want everyone on the latest and greatest, but it would be really nice if they allowed someone to drop back a version, even if only ONE version. I've been lucky (or not, Apple usually seems pretty good with updates) to only have ONE issue with updates previously and it was the move to 14.2 (maybe have been 14.1) TVOS where surround sound stopped working on anything streamed from my itunes server and I had to set it to stereo only.


Never had an issue with a MacOS/OSX upgrade or iOS over the years. Especially on something like TVOS it shouldn't be THAT hard to implement an OTA downgrade to the version you had previously been on even if they only support 1 version back (which could be an issue for people who wait several versions to upgrade, but it would still be something).

May 3, 2021 7:26 AM in response to RavenDiaval

I appreciate you going through the effort! I submitted feedback, but that is unfortunately about all I have the time for. Also the sleuthing. Same deal here, my entire library is AAC, no way for me to reasonably re-encode everything as AC3 (I also use avidemux). I'd be spending probably 100hrs doing that for all my movies and TV shows (since there is no, easy way to batch it. Even then, my computer would still be chewing on it for days and days).


I probably will try a file or two just to see for myself. I'll also try the frame rate matching Joseph suggested. I think I had tried that, but I might not have.

May 26, 2021 12:21 PM in response to azazel1024

Just an update. TVOS 14.6 didn't fix the issues. Not noticing crackling or popping in the audio, but if I wait 3 or so minutes the audio starts getting further and further out of synch and generally stops working entire after about 10-15 minutes. So everything still broken. Hopefully Apple fixes this in 14.7 and soon. I did notice they pulled their spatial audio and other audio updates from 14.6 and is putting it in 14.7. Hopefully that means they are aware of this issue and working on a fix.

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tvos 14.5 audio synch (computers/itune server)

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