Very High CPU with playback

[rainman]

Hi I am new to Jellyfin and containers on NAS so am hoping some kind soul can guide me in the right direction.

I am running a Synology 920+ NAS with 20GB RAM with Jellyfin 10.9.9 installed in a container.

As soon as I start playback on a video file (playing back in a firefox browser on a Macbook Pro) the NAS CPU shoots up to almost 100%.  The video runs ok but I am concerned about the over use of CPU.

Here is a link to the transcode log: https://pastebin.com/icdbDSiy

Any help would be much appreciated. Thanks.

[Efficient_Good_5784]

Have you setup HWA? I also have a DS920+ and using the CPU to transcode a 1080p HEVC video will make the CPU reach around 70-80% utilization.

[rainman]

I haven’t set up HWA (don’t even know what it is). I’ll have a look into it. Will that improve it do you think?

I’m not sure what HEVC video is but I’ve set up subs to be downloaded via Bazarr so I assume you are talking about the process of including them over the video? Is there a setting to just stop this if subs aren’t needed?

I haven’t figured out how to run a client on my device to lower the cpu demand on the NAS. Do you know if that is possible?

[Efficient_Good_5784]

HWA stands for Hardware Acceleration. For Jellyfin, it refers to using a GPU to handle transcoding instead of the CPU. A GPU can generally encode a video faster than a CPU.

https://jellyfin.org/docs/general/server/transcoding

If you enable HWA, the CPU utilization during a transcode on the DS920+ will be around 35-50% for a 1080p to 1080p conversion.

Go to your dashboard and into the playback section for transcoding settings.

You need to pass the GPU into the container first however if you're running Jellyfin in a Docker container.

Look at my guide if you want to see how to do so using Compose: https://forum.jellyfin.org/t-guide-runni...er-compose

[presentabsence]

If you are using a Synology DS920+ NAS you do not have Hardware with which to Accelerate.

In basic terms - if your client, web client via Firefox in this case, is not able to play the file you are attempting to play in its native format then the server must convert it into a version that your client _can_ play. There are other reasons that will initiate a transcode, but I suspect that's what is happening. Transcoding on CPU is a very resource-intensive process. Your NAS's poor little CPU will be working its ass off to convert the video faster than you can watch it. On traditional servers you can add hardware such as a graphics card and then configure Hardware Acceleration as mentioned above and offload the transcoding workload to that card instead... but not on a basic consumer grade NAS.

Alternatively, you have a limited few other options. The three that come to mind are first, consider using a Jellyfin client with broader compatibility, my understanding is somewhat dated as I don't come here often anymore but the web browser clients are limited in that regard. Second, disable transcoding in your Jellyfin server settings entirely (under Dashboard -> Playback), though be aware that if your client cannot play a video it will simply not play it (I think it gives you an error or something idk, been a long time since I've dealt with that). Or third... just let your NAS sweat trying to convert your video on CPU. You may find some files that simply cannot be converted fast enough to have an enjoyable viewing experience, though.

[Efficient_Good_5784]

If you are using a Synology DS920+ NAS you do not have Hardware with which to Accelerate.

This is false.
Look at page 5 of this spec sheet PDF for the DS920+: https://global.download.synology.com/dow...et_enu.pdf

As you can see, the CPU the DS920+ has is an Intel Celeron J4125 which has an iGPU (Intel UHD Graphics 600): https://www.intel.com/content/www/us/en/...tions.html

The only thing they can't do with a Synology at the moment is HDR tonemap due to the Linux kernel being behind and Synology not updating it.

I don't have a list, but there are Synology models that came out after 2021 (I believe) that have an AMD CPU. Those do not have an iGPU.
So for anybody else that wants to use the iGPU of a Synology unit, they just have to make sure it uses an Intel CPU and not an AMD CPU by looking up its specs.

[rainman]

As you can see, the CPU the DS920+ has is an Intel Celeron J4125 which has an iGPU (Intel UHD Graphics 600): https://www.intel.com/content/www/us/en/...tions.html

Correct! I managed to set it up and the CPU has dropped from 95% down to 6-15% when playing back... fantastic!

Go to your dashboard and into the playback section for transcoding settings.
 
You need to pass the GPU into the container first however if you're running Jellyfin in a Docker container.

Look at my guide if you want to see how to do so using Compose: https://forum.jellyfin.org/t-guide-runni...er-compose

This guide was perfect for me on the 920+: https://www.wundertech.net/jellyfin-transcoding/

I did wonder if I have setup the preferences for the encoding type:
------------------------------------------------------------------------
Enable hardware decoding for
H264: selected (this was default)
HEVC: selected  (changed this from default as should be supported: https://jellyfin.org/docs/general/admini...ion/intel/)
MPEG2: selected  (changed this from default - this was a guess)
VC1: selected (this was default)
VP8: not selected (didn't change default)
VP9: not selected (didn't change default)
AV1: not selected (I don't think this is supported with the Celeron j4125: https://jellyfin.org/docs/general/admini...ion/intel/)
HEVC 10bit:  selected (this was default)
VP9 10bit:  selected (this was default)

Prefer OS native DXVA or VA-API hardware decoders: selected (this was default)
------------------------------------------------------------------------

Does anybody have the preferred transcoding options for Synology 920+?

[Efficient_Good_5784]

I did wonder if I have setup the preferences for the encoding type:
------------------------------------------------------------------------
Enable hardware decoding for
H264: selected (this was default)
HEVC: selected  (changed this from default as should be supported: https://jellyfin.org/docs/general/admini...ion/intel/)
MPEG2: selected  (changed this from default - this was a guess)
VC1: selected (this was default)
VP8: not selected (didn't change default)
VP9: not selected (didn't change default)
AV1: not selected (I don't think this is supported with the Celeron j4125: https://jellyfin.org/docs/general/admini...ion/intel/)
HEVC 10bit:  selected (this was default)
VP9 10bit:  selected (this was default)

Prefer OS native DXVA or VA-API hardware decoders: selected (this was default)
------------------------------------------------------------------------

Does anybody have the preferred transcoding options for Synology 920+?

The J4125's iGPU can handle all the decode codecs except for AV1.

So just enable all of them minus AV1.

Likewise for the encoding format options, you can enable HEVC, but keep AV1 encoding disabled.