Solving playback issues

[home_theatre_ma]

Is anyone else having trouble playing 4K HDR + Dolby Atmos content from the Apple TV app?  When I launch a stream, it plays back smoothly for about 3-5 minutes, then the audio drops outs (to silence) for a few seconds (video is fine); audio returns briefly and playback is normal for another 30ish seconds; then the video and audio both stutter for a few seconds; then playback pauses and buffers.  From there on, it will play a few seconds at a time and then pause again to buffer.  Switching to a different title starts the process over again: 3-5 minutes are smooth, then issues start.  I do not recall this happening before the Apple TV app update that enabled Dolby Atmos.

Hardware is 4630X running latest build of the OS (9.3.0 build 4170-29) and Apple TV app (4.0 build 101) available for download.  Wired connection to Gigabit Ethernet network.  120 Mbps service from Comcast.  Roku speed test reports 80-90 Mbps downstream.

Nothing ever buffers on other Roku apps; however, I understand that Apple can run a higher bitrate (25 Mbps average) for 4K HDR compared to most other providers (around 10-15 Mbps average) - but that may only be on the Apple TV 4K device and not applicable to Roku.  As far as I'm aware, the only other service capable of running bitrates in the 25 Mbps range is Movies Anywhere, and I don't have any stuttering/buffering issues with Movies Anywhere running 4K HDR + Dolby Atmos on Roku.

EDITED 8/10/2020 to add Roku OS and Apple TV app versions.

[Realdine]

Same problem in canada. Itunes 4k hdr atmos (june-july 2020 dolby atmos update) movies stuttering (audio and video) on apple tv app. Setting audio to stereo and it plays without problems.

[home_theatre_ma]

Nice lead!  I will check my 4630X to confirm that switching to Stereo audio output fixes the stuttering problem.  I may also try restricting the Roku to Dolby Digital (AC-3) as that would disable the Atmos output, which requires Dolby Digital Plus (EC-3).  That would pretty much positively identify the Atmos update - or something related to it - as the culprit.

Anyone from Roku around to check this out for us?

[Realdine]

On dolby digital, it stutter at the same places in the movies, but just 1 sec and its fine for 15 mins. On dolby digital plus (atmos), its unwatchable. It stutter 5-10 sec every 5 mins.

[Realdine]

Did you have time to test the stereo setting?

[home_theatre_ma]

Not yet.  Still on my to do list...

[home_theatre_ma]

I just spent the better part of two hours watching an assortment of 4K HDR + Dolby Atmos titles with the 4630X set to "Dolby Digital/DTS" and "PCM-Stereo" for audio output.  Smooth sailing - no playback issues.

I switched to "Dolby Digital Plus" (EC-3, which enables Dolby Atmos) and got through about two minutes of one title before the dropout/stutter/buffer issue returned.

This is definitely related to Dolby Atmos/EC-3 output from the Apple TV app.  Hopefully, Roku will jump on this and get it fixed in good time.

[Realdine]

Thank you for testing it. I'm glad it works for you too. I hope roku or apple will fix it soon. It's so better with atmos sound.

[home_theatre_ma]

In case Roku is monitoring this thread, the recent updates to the Roku OS (9.3.0 build 4194-29) and Apple TV app (4.1 build 150) did NOT resolve the issue.

[Enigmatic88]

Same here.  Appletv with Atmos is very choppy within 3-5mins of streaming.  When switching to DD surround or DTSx the content streams fine.  My Roku 3 is flawless when streaming Appletv with Atmos.  This happening on all new Roku devices premier/stream stick/ultra.  This is very annoying, the only reason for buying  Roku is only for the 4K with Atmos audio which is very disappointing.