4K Apple TV audio sync issues?

There are a number of people who are experiencing audio sync issues after upgrading to 14.5. I had it on my AppleTV 4K. Apple support had me take it in for repair and since it was still under warranty they just replaced it with a new one. My new one has 14.4 installed and I no longer see sync issues with the audio.

I was also experiencing audio popping and crackling on the videos that showed sync issues. I hope that Apple can get these issues fixed soon. While I'm ok with keeping 14.4 on my AppleTV, I had upgraded my iPad and iPhone devices and now can no longer downgrade them back to 14.4.

We have three 4K Apple TV streaming devices in our home and we were having sync problems on all streaming services with one of them. I tried resetting, updating and using the iPhone/Apple TV sync, but the problem persisted. We got faster internet service and I installed an ethernet backhaul to the WiFi mesh unit closest to the problem Apple TV device. I even ran a dedicated ethernet cable directly from our fiber internet modem to the back of the Apple TV and still programs slipped out of sync. I swapped other Apple TV devices from elsewhere in the home into the problem room and the sync problem persisted.

As an act of desperation, I replaced the 10' HDMI cable that ran through the wall from the Apple TV to the television and the sync problem went away! The 'old' cable was only a few years old and looks fine, but I guess it degraded somehow and was causing the problem.

[Link Edited by Moderator]

Happy to report and it's without any fanfare that Apple today (20 July 2021) released the official TVOS 14.7 software update to upgrade AppleTV 4K and having tested 'Computers/Home Sharing' streaming from my iMac (High Sierra), the 7 or 8 movies I've tested so far that previously had Audio/Sync issues, now play normal and in sync, no crackle pop sound at beginning, no cutting out after several minutes!

Now maybe my eyes are playing up from all the testing but the picture quality now looks slightly less high resolution...maybe Apple had to play around with how many frames per second to get Audio/Sync fixed when 'Home Sharing'??

And no mention by Apple of fixing this major fault created by their 14.5 update: https://support.apple.com/en-us/HT207936

What's new in tvOS 14.7? This update includes general performance and stability improvements. That's it!

So Audio/Sync appears to be fixed! Well on my Apple TV anyway.

This is my first Apple Community post I've taken part in and I have to say I'm blown away by the community and the technical knowledge of many out there more so than AppleTV Tech support (I talked to about 6 different consultants) who are sadly are not even given the product for free that they are meant to be trained in giving tech support for.

Apple must love all this FREE market research through community posts they get to fix bugs of their products.

Enjoy all!

If you take the video and run it through handbrake, convert it to MP4 and select the Codec "AAC Passthru" in the audio section, it will now be able to be played on the latest Apple TV OS Big Sur, without any Audio sync issues. I had to do this with 100's of my videos.

This is has now been reported across many other support threads. The issue appears to be related to how the audio is encoded and if it is AAC, the audio and video are out of sync after a few minutes of play. I found that all the programs that are in Dolby 5.1 sound have no issues. Anything in stereo is out of sync.

https://discussions.apple.com/thread/252722595

https://discussions.apple.com/thread/252721477

https://discussions.apple.com/thread/252710380

I have a huge library of videos (over 1000 shows and movies) and now I can't watch over half of them. I am starting to get concerned that Apple isn't acknowledging the issue. That would lead me to believe that a solution isn't close.

My M1 MacMini is updated to the latest macOS and updates (just ran another one a couple of days ago).

My AppleTV auto updated last week

I run into the same problem watching the videos on my computer.

If I put a copy of the same file on my older MacMini that isn't running Big Sur, I have zero issues and the audio is working just fine.

Any suggestions? Any ETA on a fix? I ordered a new AppleTV last Friday morning but am debating if I should cancel the order since I am already trying to figure out what other options I have to watch my TV library on another system.

This has been happening with my 4k Apple TV when sharing across from my iMac 5k Retina running Big Sur (Currently 11.3.1).

I thought it was the Apple TV 4K with the problem but after much testing at my end, I've narrowed it down to Big Sur. Possibly maybe even going back to Catalina in a smaller way.

Playing back a tv show from the TV App on the iMac, the audio and video goes out of sync around the 4 minute mark. The same file does exactly the same thing when playing it back in Quicktime on the iMac.

However, playing the same file back through VLC (for example) on the iMac there are NO audio/video issues. Everything stays in sync.

So I would be tempted to say the problem is with macOS Big Sur and it's core audio.

I have made numerous feedback reports to Apple in the past month relating to the issue, my last one being only a week ago (10 May-ish) where I outlined my findings as mentioned above.

I fear nothing will be done about it any time soon, if at all. Seeing as I am a Beta Tester of which I made numerous feedback reports on bugs and problems of Big Sur before it became public, and even now that it is public and I can attest that barely any of the problems I pointed out have been remedied even to this day.

Remember that fantastic catch phrase that Steve Jobs coined... "it just works".

Well, not any more folks.

It's definitely AAC playing up at my end.

Last night I AirPlayed two TV shows from TV App on my iMac 5k Retina to my Apple TV 4K box with no audio/video sync

problems. Both this files were Dolby Digital Plus, 48000 Hz 5.1 (L C R Ls Rs LFE) audio.

But yet an AAC, 44100 Hz Stereo (L R) file went grossly out of sync within the first 3 minutes.

However, I just AirPlayed this same file from the same Mac to my Apple TV 4K but through VLC this time and it stayed in sync.

Definitely a problem in Big Sur with AAC audio for me it seems. Quite annoying.

Hi all, I just replied this to an Apple Community Specialist on a similar post which may be helpful:

Thanks Leanne for replying, yes I tried all your recommendations to trouble shoot audio sync issues on my new Apple TV 4K's 'Home Sharing' from iMac's iTunes (version 12.8.3.1) and the issue still persists. I also tried Ethernet cable plugged in direct from WiFi modem to the back of the Apple TV 4K and still Home Sharing audio sync issues.

Seems the audio sync issue is new since TVOS 14.4 updated to TVOS 14.5 and currently 14.6. The issue is consistent across all Apple TV 4k models and Apple TV HD models who did the upgrade. It also seems to be an issue on MP4s with stereo sound, instead of Dolby 5.1 sound.

I spoke to Apple again and the retailer I purchased it from to arrange either a refund or replacement.

If I go replacement and try again, it's been recommended to keep software running 14.4 out of the box and disable 'auto update' software until Apple acknowledge and fix the fault on a future upgrade.

Note: The Apple TV3 I tested here today using same Wi-Fi, same iMac/same iTunes to Home Share has no audio sync issues & never has.

Note: TVOS 14.6 which auto updated 2 days ago on my Apple TV 4K box DID NOT FIX 'Home Sharing' Audio Sync issues.

Hope this info all helps.

Hi, you can't 'reset' Apple TV to factory settings and downgrade to TVOS 14.4.

According to Apple, it resets to latest upgrade the Apple TV box installed.

But some customers have gotten a replacement Apple TV 4k due to 'Home Sharing' audio sync & sound cutting off fault and if you're lucky, a brand new box will have TVOS 14.4 pre-installed. If it does, DO NOT UPGRADE (as recommended by the last Apple TV consultant I spoke to)!

But I was unlucky when I got my new replacement Apple TV 4k yesterday - it was either 14.5 out of the box or may have auto-updated the software in the 10 minutes it took me to set the new box.

Apple tech support assured me that brand new boxes have 'auto update software' set to 'OFF', but sadly the new box had 'auto update software' was set to 'ON'.....so the audio sync issues through Home Sharing continue till Apple finally fix it....****!

FYI - I fixed the problem by downloading Plex to replace iTunes and then installing the Plex app on my AppleTV. Now all movies play without issue. It seems like iTunes and AppleTV are causing the audio problem.

Just updated my Apple TVs to 14.7 - have a mix of 3 to 4k versions - all of which had the audio sync issues - now finally fixed. It was driving me nuts, but clearly from reading a number of posts across this Community and other forums, it was a firmware issue, which we've just had to wait for an appropriate update to fix. This appears to be done - fingers crossed......

h.frommiami,

Thank you for your response. Is your iMac capable to update to macOS Big Sur? See here: How to upgrade to macOS Big Sur

Do you use security software or VPN on your network? If so, can you disable them to rule them out? Let's also have you check the firewall on the Mac. You can do this at System Preferences > Security & Privacy and select Firewall. If the firewall is blocking all incoming connections or allowing only essential services, click Firewall Options and edit the settings.

Lastly, we want to check the Home Sharing configuration just to be sure. You sound like you have this all set. Use Home Sharing to share media from a computer to other devices

If you are still having trouble, we'd like to get you in touch with Apple Support for further assistance. Contact them here: Contact Apple Support

This should all get you going down a path of resolution for this.

Finally, found a thread where others are having the exact same issue.

My set up:

Mac Mini, 2012 version running Catalina. Too old to upgrade to Big Sur.

Apple TV 4K, only had it a few months and it upgraded itself the other week and I’ve been having this issue ever since.

Everything is connected via Ethernet, and the sound bar is also hard wired, not using Bluetooth.

I don’t have a TV, the Apple TV is connected to a projector via an expensive HDMI Cable.

I have 1500 or so movies and shows ripped to my computer, some play fine but the vast majority don’t.

Like everyone else, a few minutes into a show and the audio starts to lag behind the video and there is a popping and crackling sound as well, but only on videos being streamed from my Mac Mini. YouTube, Netflix, etc., all play fine.

I can stream to my iPad from my Mac Mini, and it works fine. Also, playing a show on my computer is fine, only when I stream via the Apple TV.

As an IT Person, I have gone through and ruled out every other possible issue. I’ve used my AirPods instead of the sound bar, same issue. I’ve moved a film from my NAS drive to my hard drive, same issue. I’ve reset everything, re-established my Home Sharing link, etc., etc. Same issue. It all points to the latest software on the Apple TV 4K. I’ve even re-ripped some shows, testing different settings. Same issue.

I still have my previous generation Apple TV (Apple TV HD I think it was called). It plays the shows just fine, no sync issues.

To be honest, between this issue and the absolute rubbish design of the remote that came with it, I’m nearly ready to throw it out the window.

I am also seeing problems on my iPhone and iPad since upgrading to 14.5. Any video I stream from my NAS has sound issues if it is using AAC encoding for the audio. Apple support replaced my Apple TV 4K with a new one that has 14.4 on it. It bugs me to upgrade several times a day but at least I can watch things with it. Can’t downgrade my phone and iPad anymore so am stuck until apple fixes this for using these devices.

Like others I now experience audio sync issues on some movies accessed through Home Sharing via my Apple TV. (Apple MacBook Pro M1 16GB OSv11.4 allowing wireless Home Sharing of H.264 mp4 files from internal drive to Apple TV 4K 32K TVOSv14.6 with an HDMI connection to an old Sony Bravia TV.)

All worked fine before I noticed the Apple forced firmware upgrade from TVOS 14.4.

At the time of writing the same files on this hardware play as expected via Infuse v7.0.5 freeware application downloaded on the AppleTV on its default settings.