Plex 4K playback buffering, then audio drops out

I recently purchased a new Apple TV 4K (2021). I am using Infuse with a Plex media server over the internet (the server is elsewhere).

I can direct play anything but am noticing a weird issue when playing 4K HEVC files. Most of these will start quickly and play for about 2 minutes before needing to buffer. Once buffering is done and playback resumes, the audio is gone. I can resolve it by going forwards or backwards in the video.

After a few minutes it usually buffers again and the same issue occurs. I’ve tried multiple files and it happens almost all the time. Sometimes after 1minute 50 seconds, sometimes after 3 minutes. But always somewhere in that ballpark.

My Apple TV is connected via Ethernet, and I am getting speeds of around 190-200 Mbps down and 60 Mbps up. Infuse version 7.3.6 and TVOS 15.3 with an LG CX and Sonos Arc. All files are direct playing according to the Plex server dashboard.

I’ve tried switching between auto and legacy caching, but neither option seems to make a difference.

Wondering if there’s something I’m missing, any help would be appreciated.

Kind regards,

Can you try running a speed test in Infuse on these videos to see what kind of speeds you are getting? This can be done by navigating to Infuse > Settings > Shares > Share Name > Speed Test.

I performed two speed tests to 5% of a file, photo’s attached.

In the test with 1917 I noticed a dip to 0 Mbps for a few seconds. Shouldn’t the cache also cover such a short interruption? Also it does not explain why the sound would stop after buffering.

As a new user I can only upload one attachment, so I combined a few pictures into a single file:

As to the pauses, with such frequent dips in speed it may never get enough ahead to compensate for the drop outs in the stream. One way to test that would be to download one of the problem files to a local share and see if being on a LAN stops the pauses.

Another possibility is to start one of these from the remote share and immediately pause it and watch the progress bar for the cache to build up a while then continue the movie and see if the pauses stop. This is with the streaming cache set to Auto in the preferences.

Only a wild guess, on the audio issue is that when the movie hits a snag it changes from the multi channel audio to stereo thinking the video is over and it gets the sound system confused when it comes right back.

What do you have the audio output on the ATV set to? (Auto or 5.1 or stereo etc)