*FIXED* 4K buffering on one Plex server but not the other. Both sourcing the same content

Plex Media Server NAS & Devices
1

Hi all,

So I’m having a strange issue that I’m struggling to troubleshoot and would appreciate some assistance with.

I have two Plex media servers; one on a remote hetzner server that I use for family and friends and one on a raspberry Pi4 (4gig) that I use for direct play at home. They both access the same media on Google drive via rclone mounts.

Using a Shield 2019 tube I can direct play 1080p content from both devices flawlessly, however with 4k content only the remote server plays properly. The content being served by the Pi4 constantly stops and buffers.

So if the source content is the same, the client is that same and both servers are using the same rclone mount configuration, why would one be struggling and the other one playing back fine?

Any thoughts?

EDIT:
Upon closer inspection I discovered I had a program running on start up (cpulimit) that limited the CPU usage of Plex to 75%. I installed this a while back to troubleshoot some crashing that had been occurring during library scans and evidently forgot it was still set to run. Removing it immediately fixed the playback issues.

2

2160p is 4x the amount of raw data. Given it must receive then retransmit locally, you likely have reached the I/O limit of what it can do.

3

Hi Chuck, could you elaborate at all regarding the IO limit?
Are you saying the Pi4’s hardware is the bottleneck then? I was under the impression that direct playing 4k material was possible with the device.

4

I don’t know anything about a Pi system — Don’t own one.

What I do know:

  1. When we added ARMv8 support for the NAS platforms, I had to be very careful not to overload them. (I was on that launch team)
  2. In 1080p video, it’s very rare to see video bitrates > 100 Mbps. This is why most televisions are 100 Mbps network adapters.
  3. 2160p is 4x the amount of video (worst case) over 1080p because the geometry is 4x larger.
  4. WAN streamed 2160p is less than 100 Mbps ( places like NetFlix, Amazon, etc) to be most compatible with televisions and the ethernet adapter limits
  5. I have my own 2160p material here and it’s quite common to see bitrates > 100 Mbps.

I deduced the Pi is the limitation because:

  1. Same video works when played to the same television from a different (more powerful server)
  2. – Ethernet adapter in the television is not the limitation
  3. – Home LAN is not the limitation
  4. – Source video file is not the problem

By process of elimination – Pi is the limitation and cannot keep up with demand.

Unknown: Which facet of the I/O. Disk or Network ?

5

Thanks for your assistance Chuck, however it appears it wasn’t a hardware limitation after all.
Upon closer inspection I discovered I had a program running on start up (cpulimit) that limited the CPU usage of Plex to 75%. I installed this a while back to troubleshoot some crashing that had been occurring during library scans and evidently forgot it was still set to run. Removing it immediately fixed the playback issues.
Thanks again for taking the time to try and help though. It was much appreciated.

6

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.