Stuttering on direct play of higher resolution files

[mossedoughnuts]

Hi, I'm new to this i would like to thank before hand for the help i appreciate it. I am having trouble playing some media, below the details.

Version: Jellyfin server version 10.9.10
Installation Method and Platform: Installed on a bare-bones Windows 11 machine.
Brief Description: Stuttering on direct play of higher resolution files, while lower resolution files play without issues.
Full Explanation: I’m experiencing stuttering when playing higher resolution media on my LG OLED55C2PUA TV with webOS 8.3.0-29. 
For less demanding files, such as 360p H.264 SDR with AAC stereo audio, they play perfectly fine. However, when I try to play more demanding files like a 1080p H.264 SDR video or Video:4K HEVC HDR with Audio: English - Dolby Digital+ - 5.1 - Default, the playback stutters. Specifically, the video plays for two seconds, stutters, plays for 15 seconds, then stutters again.
Jellyfin reports that the video is using direct play when this happens. If I lower the Quality to something significantly lower, the video transcodes and plays smoothly, but the quality suffers, which I want to avoid. The issue seems most common with files higher than 1080p.
Client: My primary client is the LG OLED55C2PUA TV, using the Jellyfin app on webOS 8.3.0-29 and the jellyfin app updated to the latest. Notably, this issue only occurs on the TV. When I use my laptop with Chrome, Jellyfin direct streams flawlessly without any dropped frames. and this leads me to belive that the issue is just on the client side. any suggestions?
Additional Context:

• I've tried using both Wi-Fi and a wired connection, reinstalled the server, and changed various transcoding settings. The issue persists regardless of these adjustments. also i don't see any settings on the client side that would help.
  

I’m hoping there’s a setting I’m overlooking or another solution that can help resolve the stuttering when using direct play on my LG TV.

Thanks so much for your time.

[TheDreadPirate]

Can you share your jellyfin logs via pastebin?

[mossedoughnuts]

Thanks for your response! Something interesting happened. While trying to provide a clean log for one file, I found around 18 log files in the folder. Since I wasn’t sure what each one was for, I decided to manually delete everything I could. One log file couldn’t be deleted while the server was running, so I stopped the Jellyfin service, deleted it, and then rebooted the PC.

After restarting with a clean log, I tested some heavier media, starting with a 1080p file, which worked perfectly. I then tried a 4K file, and it played smoothly as well. However, I initially experienced stuttering with one specific file. Interestingly, after playing another 1080p file that worked fine, I went back to the problematic file, and it played without issues—15 minutes in so far.

This makes me think the issue might be intermittent, as I can’t pinpoint why it suddenly started working. I’ve tried multiple reboots, reinstalls and different clients in the past with no success, but it seems like the log cleanup may have helped. I’m hopeful the issue is resolved for now.

In your experience would this be a cause of problems?

Thanks for your time

[TheDreadPirate]

There is not information to narrow down the cause. It could be many many different factors.