What are the variables that can cause buffering?

Plex Media Server
1

Server Version#: 4.108.0
Player Version#: N/A

I’m hoping to just get some general troubleshooting information here, but I provided some background on why below. Once I’ve done more troubleshooting I’ll create another post for help trying to solve the actual problem (assuming I can’t solve it).

From all my reading, here are the main variables (in no particular order) that could be involved in causing recurring buffering that makes Plex unwatchable for the user. Am I missing anything?

  • Client quality settings / video transcoding (vs. direct play)
  • CPU / transcoding (including audio)
  • Server-side bandwidth
  • Client-side bandwidth
  • File bit rate
  • Subtitle burn-in, image-based subtitles
  • Any physical part of the chain (e.g., cables, client devices, etc.)
  • Disk speed/health

I know some of these are really related to each other, such as file bit rate and bandwidth, but I’m trying to create a list of the variables I should pay attention to when troubleshooting.

Background: I have about 5 family members that stream from my Plex Unraid server (i5-11400, HW transcoding works). One of them has consistently had buffering problems (though not every single time), making Plex unusable for them. The others say they have no problems. I’ve been troubleshooting on/off for 2 years, trying some different things, checking logs (and not seeing anything), but not really organized and systematic about it. I’m now ready to get serious and try to fix this problem so I want to have a clear understanding of how to structure my troubleshooting so I’m both efficient and thorough. I’m no expert, but I’m fairly technical and have a good understanding of most of the variables listed above.

If you made it this far and have any advice on how you would go about troubleshooting something like this (in general), please do share. Thanks.

2

Bump. Any knowledgeable folks here willing to share their thoughts?

3

More than just bit rate, how was the file produced? A lot of files people download aren’t fit for streaming.

1 Like
4

high latency can also affect streaming, even if throughput is high.

for example, satellite, fixed wireless, congested cellular, etc.

you could also try traceroute (windows tracert) from both directions of client and server networks, to see if there are any intermediary high pings connections.

also, if it seems only affecting certain user(s), ask if they are using wifi, and if they are in an apartment or busy neighborhood with a lot of conflicting wifi networks.

lots of apartment wifi are very bad for consistent speed.

its like a room full of people all shouting, but no one can understand any conversation, just making out bits and pieces.

1 Like
5

Can you say more about this? What variables are involved in making a file unfit for streaming?

6

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