2025-05-27, 05:43 PM
(This post was last modified: 2025-05-27, 05:53 PM by bitstream. Edited 2 times in total.)
Just did a test on the cli directly feeding ffmpeg with the same file i tested above, however without streaming of course. So the runtime is not directly comparable to the results above but the difference between the runtime of the test without hardware acc and with hardware acc is comprable.
without hardware acc:
time ffmpeg -i /nas/test.avi -c:v libx264 -f null -
real 8m11.390s
user 30m8.818s
sys 0m45.056s
with hardware acc:
time ffmpeg -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -i /nas/test.avi -vf 'format=nv12,hwupload' -c:v h264_vaapi -f null -
real 2m49.731s
user 1m41.904s
sys 0m11.403s
The relevant duration is "user" (that's duration times cpu cores used). The difference is massive: The encoding has used 18x less cpu time and the whole processes finished 4.5x faster using the iGPU compared to no hardware acceleration.
This would have been the factors i was expecting to see in JF aswell. Why is there such a big difference? I'm aware that there is also audio transconding and pot. sub titles burn-in (not the case here), but compare to video processing, thes tasks seem to consume rather low cpu power.
without hardware acc:
time ffmpeg -i /nas/test.avi -c:v libx264 -f null -
real 8m11.390s
user 30m8.818s
sys 0m45.056s
with hardware acc:
time ffmpeg -hwaccel vaapi -vaapi_device /dev/dri/renderD128 -i /nas/test.avi -vf 'format=nv12,hwupload' -c:v h264_vaapi -f null -
real 2m49.731s
user 1m41.904s
sys 0m11.403s
The relevant duration is "user" (that's duration times cpu cores used). The difference is massive: The encoding has used 18x less cpu time and the whole processes finished 4.5x faster using the iGPU compared to no hardware acceleration.
This would have been the factors i was expecting to see in JF aswell. Why is there such a big difference? I'm aware that there is also audio transconding and pot. sub titles burn-in (not the case here), but compare to video processing, thes tasks seem to consume rather low cpu power.