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+--- Thread: SOLVED: High CPU usage (/t-solved-high-cpu-usage--14019)
High CPU usage - HoubaCZ - 2025-10-08
Hi,
So I recently got into homelabbing, if you can even call it that, so I'm still bad at this, so I apologize for any mistakes in advance. Following some tutorials, I installed CasaOS on my old PC, which runs Debian, and through that I installed Jellyfin (Nvidia GPU). Now my problem is that when I'm trying to watch a film or a series, my CPU usage spikes up to like 85%. I read some posts that said it might have something to do with subtitles, but I have them turned off. I have Nvidia drivers installed, and my GPU usage does go up to like 12% from 0%. Sometimes the video lags for like 3 seconds and the audio keeps going. Is it possible that my CPU is just too old? What would be the solution to this?
I have attached some logs that I got from the Jellyfin dashboard, although I had to delete some lines from the beginning of the log.txt since it was too large to attach.
Specs:
Jellyfin: 10.10.6
GPU: 1060(6gb)
CPU: I5-8400
RE: High CPU usage - nyanmisaka - 2025-10-09
1. Hardware decoder not enabled
2. Audio transcoding occurred
RE: High CPU usage - HoubaCZ - 2025-10-09
1. That doesnt really help me much. I thought it was enabled when you enable hardware acceleration in settings, https://pasteboard.co/00itcp5nsNr0.png this is how I have it set up.
2. Can audio transcoding really use up that much of my cpu?
RE: High CPU usage - nyanmisaka - 2025-10-09
You need to enable HEVC 10bit hardware decoding. Your video is in this format.
RE: High CPU usage - 34626 - 2025-10-09
Hello to you :-)
1. Yes transcoding can requre a lot.
My questions to you:
Is Jellyfin running in docker? I would recommend that, its very easy to backup and restore.
I dont have experience with Nvidia, but have you installed the Nvidia driver on the PC?
Have you read up on hardware acceleration: https://jellyfin.org/docs/general/post-install/transcoding/hardware-acceleration/
What kernel version do you use? I Use Debian 13 trixie, so im asking because you mention CasaOS is based on Debian.
RE: High CPU usage - HoubaCZ - 2025-10-09
(2025-10-09, 11:21 AM)nyanmisaka Wrote: You need to enable HEVC 10bit hardware decoding. Your video is in this format.
Thanks that helped, now my CPU usage is only at 20%. Should I enable all other formats? I read somewhere that only certain GPUs support certain formats.
RE: High CPU usage - HoubaCZ - 2025-10-09
(2025-10-09, 11:34 AM)34626 Wrote: Is Jellyfin running in docker? I would recommend that, its very easy to backup and restore.Yes, Jellyfin should be running in Docker. I believe that CasaOS does that automatically.
(2025-10-09, 11:34 AM)34626 Wrote: I dont have experience with Nvidia, but have you installed the Nvidia driver on the PC?I have installed Nvidia drivers. Specificaly - Driver Version: 535.247.01 CUDA Version: 12.2
(2025-10-09, 11:34 AM)34626 Wrote: Have you read up on hardware acceleration: https://jellyfin.org/docs/general/post-install/transcoding/hardware-acceleration/
I tried to read up on hardware acceleration a bit, but I don't understand it much. As I said, I'm quite a noob regarding this.
(2025-10-09, 11:34 AM)34626 Wrote: What kernel version do you use? I Use Debian 13 trixie, so im asking because you mention CasaOS is based on Debian.
I believe that I have Debian 12 bookworm.
RE: High CPU usage - 34626 - 2025-10-09
(2025-10-09, 11:49 AM)HoubaCZ Wrote:(2025-10-09, 11:34 AM)34626 Wrote: Is Jellyfin running in docker? I would recommend that, its very easy to backup and restore.Yes, Jellyfin should be running in Docker. I believe that CasaOS does that automatically.
(2025-10-09, 11:34 AM)34626 Wrote: I dont have experience with Nvidia, but have you installed the Nvidia driver on the PC?I have installed Nvidia drivers. Specificaly - Driver Version: 535.247.01 CUDA Version: 12.2
(2025-10-09, 11:34 AM)34626 Wrote: Have you read up on hardware acceleration: https://jellyfin.org/docs/general/post-install/transcoding/hardware-acceleration/
I tried to read up on hardware acceleration a bit, but I don't understand it much. As I said, I'm quite a noob regarding this.
(2025-10-09, 11:34 AM)34626 Wrote: What kernel version do you use? I Use Debian 13 trixie, so im asking because you mention CasaOS is based on Debian.
I believe that I have Debian 12 bookworm.
I can't access CasaOS' website, but you could consider Debian 13, theres a newer kernel with great improvements.
I dont know how much you have invested, but Intel has some great GPUs, which would allow you to use Intel Quick Sync, which is a lot better then Nvidia/AMD, but this is just a kind information.
As i understand, your transcoding issue sounds to be fixed, but you are always welcome to reach out again :-)
RE: High CPU usage - nyanmisaka - 2025-10-10
(2025-10-09, 11:39 AM)HoubaCZ Wrote:(2025-10-09, 11:21 AM)nyanmisaka Wrote: You need to enable HEVC 10bit hardware decoding. Your video is in this format.
Thanks that helped, now my CPU usage is only at 20%. Should I enable all other formats? I read somewhere that only certain GPUs support certain formats.
According to the documentation you can also enable the VC1 hardware decoder. The remaining formats require the CPU to handle video decoding.
https://developer.nvidia.com/video-encode-decode-support-matrix#