I’m getting higher CPU usage than normal when Plex is generating thumbnails. The Plex transcoder is at 85-90% on a Skylake 7900x. I have hardware acceleration enabled for my nVidia GTX 970, but the GPU isn’t being used at all. Did something change with hardware acceleration in a recent update that’s causing the unusually high CPU usage? Did anything else change? I don’t ever recall getting anywhere near 80% when generating thumbnails before.
When generating thumbs at my house Plex uses - and always has used - every squirrel available (and buses in a Squad of Reds from the UK).
Trust me - I just spent the better part of a week creating a new Plexiverse -and thumb generation is something I am VERY familiar with…
AFAIK Hardware Encoding isn’t used in VPT generation:
from 2018, but still may ring true…
1 Like
@JuiceWSA LOL, alright, well I guess I never noticed before. It would definitely be nice if hardware acceleration could be used for thumbnail generation. I thought I had a good CPU, but man was it hurting!
2 Likes
Yep still totally true sadly.
I agree absolutely. When I get a moment I’m gonna take a look if there is already a feature request for this. If not I will create one.
I actually found this
It seems rather bizarre that a feature suggestion is locked due to the 90 day elapsed thing.
Especially with active votes.
fixed.
1 Like
Thanks Otto,
@Xhaka @OttoKerner Great, thanks. I put in my vote.
Me too.
without GPU assistance, any x265 content will hit the cpu pretty hard when generating thumbnails etc.
Wow, I never thought about that…
I casually added an item to Handbrake the other day - time for a quick encode… "4 Hours and 16… 17… 18… 19… WT… oh… I see… HEVC.
I’m hooked on VPTs - not yet addicted to HEVC - so we know what to do armed with that info…
lol
hevc/x265 is the devil.
which is why 4k is so difficult.
people just assume that 4k is just bigger 1080p.
unfortunately it just isn’t that simple. especially in conjunction with hdr/color space differences that are not compatible (ie washed out colors etc).
Does plex server use hardware transcode to assist in making thumbnails for the preview?
1 Like
Currently, Plex does the thumbnail generation on the CPU.
This can be done entirely using the hardware decoder AND hardware jpeg encoder, for any GPU that has a MJPEG hardware encoder (Intel does, looks like nvenc doesn’t).
ffmpeg -hwaccel vaapi -hwaccel_device /dev/dri/renderD128 -hwaccel_output_format vaapi -i input.mkv -r 1/2 -c:v mjpeg_vaapi -vf 'scale_vaapi=w=320:h=-1:format=nv12' -global_quality 90 -f image2 img-%06d.jpg
This works on my Xeon E3-1245V6 using Linux with ffmpeg 4.0.4 with very little CPU usage. Creates the jpegs at the same size and rate that Plex currently does.
Based on my testing, it’s limited by the speed of the hardware decoder, the JPEG encoding is practically free time wise.
Would be great to have Plex use the hardware for this task.
This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.
