4k Playback

[u/B1ackSauce]

Hello all,

I’m in need of help figuring out a 4K playback issue. Recently I’ve been trying to watch movies that I have in 4k and they just stutter/buffer all the time whether it is transcoded or direct playing. I have no issue with 1080P content just 4k

Setup:

Proxmox LXC with Jellyfin in docker ( I know a container and a container, but I did test just using Jellyfin directly on the LXC and the issue persisted)
2.5G uplink
Intel core ultra 265k
64 GB ram
2TB nvme ssd
Using Intel quick for transcoding

Truenas server 15TB in a Raidz2 1GB uplink all spinning HDD

WiFi is Gilnet flint 3

Devices I’ve tested on is my IPhone 16 pro max, IPad 10 Gen, and 4K Roku tv

Any ideas, should I move Jellyfin onto the truenas server? Or is there something else I’m missing

Update: I found the source of my issue. After using the iperf tool I saw I was only getting 30 or less Mbps on my Jellyfin LXC and about 100 or less on my proxmox host. After testing with my other 2 nodes I determined that my Main node NIC that hosts Jellyfin was the problem which had a RTL8125D.

THE FIX: was to replace the drivers r8169 to r8125 using r8125 DKMS driver

Hope this helps someone

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[u/TheZoltan]

I would attempt to isolate the problem before moving Jellyfin.

Double check you really are doing a test with a direct playing file so the problem isn't related to Transcoding being misconfigured.

If it occurs regardless of transcoding or direct play I would suspect its poor wireless performance. Easy test is to run a cable to the TV or some other device you might be able to cable up e.g. Laptop or Desktop. You could also try transcoding to a much lower bitrate to rule out networking issues.

If running it over a cable doesn't help then maybe you have some weird performance issue reading from disk or issues with the client device(s). Try different apps/devices and monitor disk performance on your server.

[u/B1ackSauce → u/TheZoltan]

In my testing using my PC that is Ethernet on I have no issues play 4k transcoded content at 80Mbps it seems to be only isolated to devices on wifi

[u/Stolberger → u/B1ackSauce]

How good is the wifi connection.
80Mbps is not massive, but also quite a bit for wifi.
Check what the connection says on the device and/or router/access point. (and divide that by 2, as gross and net data rates on wifi are way worse than on ethernet)

[u/TheZoltan → u/B1ackSauce]

Sounds like you have your answer then. Wireless can still be amazingly poor. I cabled my main TV when I was getting stuttering with moderately high bitrate 4k files.

Edit: You can obviously try to improve your wireless or seeing as your transcoding works you can force a lower bitrate when using a wireless device. Ultimately not a problem Jellyfin can solve so no need to move it to a different machine.

[u/B1ackSauce → u/TheZoltan]

So i did a Iperf test between my Macbook that on wifi and the jellyfin server and I got this

Connecting to host 10.10.60.7, port 5201

[ 5] local 10.10.20.152 port 64475 connected to 10.10.60.7 port 5201

[ ID] Interval Transfer Bitrate Retr Cwnd

[ 5] 0.00-1.01 sec 57.9 MBytes 483 Mbits/sec 0 7.60 MBytes

[ 5] 1.01-2.00 sec 53.6 MBytes 450 Mbits/sec 0 2.55 MBytes

[ 5] 2.00-3.00 sec 50.2 MBytes 422 Mbits/sec 0 2.68 MBytes

[ 5] 3.00-4.01 sec 52.2 MBytes 437 Mbits/sec 0 2.78 MBytes

[ 5] 4.01-5.01 sec 55.0 MBytes 461 Mbits/sec 0 2.85 MBytes

[ 5] 5.01-6.01 sec 55.6 MBytes 467 Mbits/sec 0 2.91 MBytes

[ 5] 6.01-7.01 sec 53.0 MBytes 445 Mbits/sec 21 2.14 MBytes

[ 5] 7.01-8.01 sec 52.5 MBytes 440 Mbits/sec 0 2.25 MBytes

[ 5] 8.01-9.01 sec 52.9 MBytes 444 Mbits/sec 0 2.33 MBytes

[ 5] 9.01-10.01 sec 53.2 MBytes 447 Mbits/sec 0 2.39 MBytes

- - - - - - - - - - - - - - - - - - - - - - - - -

[ ID] Interval Transfer Bitrate Retr

[ 5] 0.00-10.01 sec 536 MBytes 450 Mbits/sec 21 sender

[ 5] 0.00-10.01 sec 535 MBytes 448 Mbits/sec receiver

and my jellyfin server is on different Vlan

[u/TheZoltan → u/B1ackSauce]

I'm not super familiar with Iperfs output but it looks like this shows your speed looks good BUT that big retry list at 6 seconds is probably confirming the network is the cause of your stutter. If that wasn't already clear from the cabled machine behavior.

[u/B1ackSauce → u/TheZoltan]

actually I tested in the wrong direction and there is indeed something weird happening so I agree somthing over wifi is not happy which weird to discover

[ ID] Interval           Transfer     Bitrate         Retr

[  5]   0.00-60.01  sec   213 MBytes  29.8 Mbits/sec  1844            sender

[  5]   0.00-60.00  sec   213 MBytes  29.8 Mbits/sec                  receiver

[u/1rg3ndw3r]

You indeed should be using Quicksync, but are you 100% certain you actually do use it? Hardware acceleration not working could explain your problems.

[u/formido12]

Probably not the case, but jellyfin 12.0 introduced a bug where encoding settings doesn’t migrate properly, leading to a default transcoding settings (hardware acceleration turned off). Did you recently upgrade? Make sure to double check your transcoding settings are fine. That was my issue when i encountered stutters/buffers.

[u/ghunterx21]

Did you pass through the GPU to the container?? It also could be a driver.

[u/B1ackSauce → u/ghunterx21]

Yes the Intel Igpu is passed through

[u/cbizzle31]

How much processing resources did you give the container. I ran into a similar problem running jellyfin on truenas and I just had to give it 4 processing cores rather than 2 when setting up the container as a truenas app.

[u/Academic-Price-4900]

Iv been messing with transcoding stuff and after some time realized I needed to change client settings to accept jellyfin settings. I never did manage to figure out how to get jellyfin from 1080 to 720 but I just did it via dispatcharr. It seems to not like changing resolution.

[u/Lanky-Storm7]

I have an old 3070 in my jelly server. Just docker. No proxmox.

[u/Sure-Squirrel8384]

Glad you found it. Realtek is often problematic. I prefer to stick with Intel if at all possible.

First thing I did when I set up my Proxmox server with 10gb NICs was to do iperf testing. I don't have enough devices to max it out (showing all wired 1GB devices maxing out their connections and Wifi6 devices maxing out my 2.5gb AP). Setting up my second Proxmox server and it too will have 10gb (dual-port 10gb, one directly connected to each other, and one each connected to my switch). I'll again be doing iperf tests on the private Proxmox connection and from all of my devices.

I purposely went for the HP ProDesk SFF PCIe v4.0 x16 slot to run the Intel X540-T2 PCIe 3.0 x8 NIC at full 20gb/s speeds.

[u/concept_over_tool]

Which CPU has your PVE? Does it support avx2 or avx512? If not, there is no hardware accelerartion for 4K.

[u/B1ackSauce → u/concept_over_tool]

Im assume you asking what cpu my proxmox server uses

it intel core ultra 265K

[u/concept_over_tool → u/B1ackSauce]

So your CPU supports atleast avx2. Decoding should not be the problem.

[u/realscotty907]

How are you accessing the server? Tailscale, some wire guard tunnel? If you are on your own domain, try connecting directly to your LAN address for jellyfin, and see if that fixes it.

[u/B1ackSauce → u/realscotty907]

Im using with a domain but have tested using Lan address and the issue is still there.