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SOLVED: i3-12100 transcoding performance (Expectation vs reality?) - Printable Version

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+--- Thread: SOLVED: i3-12100 transcoding performance (Expectation vs reality?) (/t-solved-i3-12100-transcoding-performance-expectation-vs-reality)



i3-12100 transcoding performance (Expectation vs reality?) - radiator - 2023-07-28

I recently upgraded my home server to an i3-12100 to enable hardware transcoding.  During my research on which CPU to choose, I often saw comments about the recent 100-series CPUs that said things like, "just get the 100, it transcodes 3-4 streams at once without breaking a sweat"

I got hardware transcoding set up and configured and did some testing using the Jellyfin web client to force transcoding.  One 4k stream does great, two start to struggle, and three is not happening.  I'm curious how my experience lines up with others' and if there are settings I could change to make transcoding use fewer resources.  I'm including the ffmpeg log and a screenshot of intel_gpu_top (attached) while transcoding just one 4k stream.

Jellyfin 10.8.10 on Linux Docker using the linuxserver.io container

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RE: i3-12100 transcoding performance (Expectation vs reality?) - TheDreadPirate - 2023-07-28

That ffmpeg doesn't appear to be complete. After it starts transcoding, there should also be logs at the bottom indicating how fast it is transcoding.

You also don't mention what resolution you are transcoding to. 4K to lower bitrate 4K? 4K to 1080P? 4K to 3-4 1080p (or lower) streams should not be a problem. 4K to lower bitrate 4K is significantly more taxing. I am assuming you are going 4K to lower bitrate 4K. One 4K transcode is roughly 4x the load of a 1080 transcode. If you enabled transcoding to HEVC, you might be able to get more performance, at the cost of quality, if you disable that and let it transcode to H264.

With all that said, what you've described is about right. If you need more transcode capacity, you will need a dedicated GPU.


RE: i3-12100 transcoding performance (Expectation vs reality?) - radiator - 2023-07-28

Thank you for these comments and for taking a look!  My intent was to transcode from 4k --> 1080p but I guess I'm not sure what actually ended up happening.  I'm attaching the full log that should have any extra info you were after.

i do currently have transcoding to HEVC enabled, so good to know I could try disabling that if I do need more performance.


RE: i3-12100 transcoding performance (Expectation vs reality?) - TheDreadPirate - 2023-07-28

Quote:  Stream #0:0 -> #0:0 (hevc (native) -> h264 (h264_qsv))
......
  Stream #0:0: Video: h264, qsv(tv, bt709, progressive), 3840x2160 [SAR 1:1 DAR 16:9], q=2-31, 59423 kb/s, 23.98 fps, 90k tbn (default)
......
frame=  87 fps= 77 q=12.0 size=N/A time=00:00:03.52 bitrate=N/A speed= 3.1x

Looks like the test you ran was going 4K HEVC to 4K H264.  I'm assuming this was the only transcode running for this log file?  If so, at the speed this is going two 4K streams is probably the max you will get.  And this is about right for an iGPU.  You would get quite a few more if they were 1080p streams.  You can squeeze a bit more performance by decreasing the quality (increasing CRF number), though I don't recommend this, and using a ram disk for transcodes (requires additional setup).

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