Apple 4k TV Audio Stutters

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Level 1

9 points

Apple 4k TV Audio Stutters

I've recently noticed, while watching anything in 4k (iTunes / Netflix), that the audio will stutter after a few minutes. I can go back to the main menu, and back into the movie and the problem is gone for a few minutes.

I have a 55C7OLED TV, Bose 1SR Soundbar, Apple TV is set to 'automatic' on sound. I plugged the Apple TV into the TV via a 4k HDMI certified cable, and then an optical cable to the sound bar. I watched several 4k movies over the week with zero issues, until today. I started a movie (Wonder Woman) and it was fine for a few minutes, the video is fine but the audio is hit or miss, mostly miss. I fired up Baby Driver, and it was the same result. The audio would stutter, drop off, stutter again, and drop out... rinse/repeat. For kicks and grins, I put on Harry Potter (1080p) and it played perfectly... which lead me to think it's a bandwidth issue; however, the ATV4k is hardwired to my internet, and as of these tests I'm pulling 100MB down.

Things tried:

Turned off all devices, and turned the back on (TV, Routers, Soundbar)

Set the DNS on the device to the DNS of my internet provider, it was set to my router.

Rebooted the device.

Rebooted the router.

Rebooted the cable modem.

Changing the audio to DD5.1, from Best Available.

Ran the HDMI cable check, came back fine (Dolby Vision).

Switched over to wireless, 2.4 and also 5GHz.

Swapped routers (I have an ASUS and an Apple Time Capsule).

Unplugged the ATV4k.

None of the above worked beyond a few minutes.

I'm hopeful this is an annoying fluke, but if someone else has seen this and has a suggestion... please, let me know. When all of your movies exist in the iTunes cloud, mostly in 4k... this really makes for a frustrating experience.

Apple TV 4K, tvOS 11, 32GB

Posted on Oct 13, 2017 4:39 PM

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Answer 1

Best reply

Crumbz46 Author

Level 1

9 points

Oct 21, 2017 3:37 PM in response to Uncivil2

I ended up replacing my cable with the approved one from the Apple Store, but it appears the problem was of my own doing all along. My TV supports Dolby Atmos, my sound bar does not. Since the TV setup hadn't changed since purchase, and this problem only presented itself recently I didn't think to look at those settings. I had Atmos turned on, and once I turned it off the problem went away. I didn't try putting the other cable back into the mix to close the verification loop, though. Since it's working now, I'm just going to let it ride as is.

Final solution:

Turned off Dolby Atmos within the TV settings

Set Apple TV to 4k Dolby Vision at 60Hz

Set Apple TV Audio to Dolby Digital 5.1

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Answer 2

z-rizza

Level 1

13 points

Jan 4, 2018 5:00 PM in response to Crumbz46

I’m a few months late but wanted to acknowledge this response. I’d purchased my Apple TV 4K when I had a 4K TV that didn’t support HDR and had no issues at all. I recently upgraded to a new Samsung TV that supports 4K HDR and WCG and immediately started seeing the sound and picture cut out when watching both Netflix and iTunes purchases. Up until today I’d played with every single AV setting on both the TV and the Apple TV 4K with no success. Today I finally decided to just bite the bullet and pick up the Belkin 4K capable HDMI cable that Apple sells, if for no other reason than to eliminate that as a potential cause. Turns out that was the problem the whole time. My almost-new Amazon HDMI 10.0 cables couldn’t handle the 4K HDR video stream.

TL;DR: Spend the extra couple of bucks for certified HDMI cables. There’s a high probability it’ll fix your problem, but if not it’ll at least eliminate the variable.

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Answer 3

Crumbz46 Author

Level 1

9 points

Oct 14, 2017 5:00 AM in response to Crumbz46

I did a factory reset on the APTV4k, leaving it at DV/Best Audio and it produced the problem after a few minutes.

Further testing has provided this information:

If I kick the audio down to Stereo, and leave the picture set to Dolby Vision... it plays fine (but sounds meh).

If I switch the audio to Dolby Digital 5.1 and set the picture to 4k HDR 60Hz... it plays and looks fine.

If I leave the audio set to DD 5.1, and set the picture to 4k Dolby Vision 50Hz... the audio stutters and drops in and out.

Seems if I try to do both Dolby Vision with DD5.1 or Best Sound, it produces bandwidth / buffering issues. I prefer the DV picture to HDR, both look great, but DV just looks better to me.

Again, this just started yesterday (10/13/2k17).

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Answer 4

Uncivil2

Level 1

9 points

Oct 14, 2017 7:35 AM in response to Crumbz46

Having the same issue, every 2 minutes or so the audio cuts for 5 seconds. Video settings are 4k HDR 60. I've been noticing it in iTunes and both NBC Sports apps. The fact is happening to me in those two sports apps would suggest to me that it isn't a cable bandwidth issue, since they only display 720 or maybe 1080p. Haven't been able to adjust any settings to fix the issue...

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Answer 5

Uncivil2

Level 1

9 points

Oct 20, 2017 5:49 AM in response to Crumbz46

Figured out 2 fixes for me, hopefully one of them will help you. Initially I ordered a new HDMI cable to see if that would fix the issue, but found a fix in the interim.

Fix #1: Check you Chroma/Color Space setting. Mine was set at 4:2:2 with the 4k HDR 60Hz and this seems to have been the cause for the, frequent, few seconds drop/stutter of audio. Changing the setting to 4:2:0 fixed the issue, allowing me to set the Audio Setting to "Best Quality Available". No more drops or stutters after this change.

Fix #2: Get a better/newer HDMI cable. The original cable I was using, and the few I changed with other devices to test as well, were 2.0b and had only been purchased a few months ago from Amazon directly. Even though all of the cables passed the Check Cable Test for 4:2:2 and 4K HDR 60Hz, they clearly shouldn't have been given the pass. I bought the Belkin HDMI 2.1 (48G) cable from Apple, and this now allows me to set my device for 4K HDR 60Hz with 4:2:2. Now I can set my device to the best available video settings and audio settings with no issues.

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