I notice that checking “use hardware encoder” makes the export slower on my computer, by a factor x2.
Its really weird because I’ve got an nvidia capable GPU:
[hevc_nvenc @ 000000000503c680] Loaded Nvenc version 9.1 [hevc_nvenc @ 000000000503c680] Nvenc initialized successfully [hevc_nvenc @ 000000000503c680] 1 CUDA capable devices found [hevc_nvenc @ 000000000503c680] [ GPU #0 - < GeForce GTX 960 > has Compute SM 5.2 ] [hevc_nvenc @ 000000000503c680] supports NVENC [hevc_nvenc @ 000000000503c680] Using global_quality with nvenc is deprecated. Use qp instead. ...
I’d like to export as fast as possible the movie I made from GOPRO recordings.
I tried with both H.264 Main Profile & HEVC Main Profile and got the same results:
- without hardware encoder: ~3:05
- with hardware encoder: ~1:35
- for a 34s output movie of 2 clips with no transition between
- ProcessExplorer shows high CPU usage (99%) and no GPU usage (<1%)
My Nividia driver is up to date.
Shotcut is up to date.
I read the FAQ especially https://shotcut.org/FAQ/#how-does-shotcut-use-the-gpu-or-not
But I’m surprised to:
- see ~ x2 export time
- see no GPU usage
Also between the presets and hitting “Reset”, things change which is confusing.
Whatever I try, it is faster without checking “use hardware encoder”.
Could you help me figure out why?
I tried various rate control settings.
NVIDIA instant replay is OFF.
Wow i just found something.
Unchecking “Parallel processing” and now it takes ~15s with hardware encoder and ~45s without.
Yeah faster with hardware \o/ !!!
(GPU usage still <2% though)
But the output file size doubles with hardware encoder ?!
hmm MediaInfo shows : CABAC / 1 Ref Frames vs CABAC / 4 Ref Frames
it appears linked to the B frames settings.
Can somebody explain which value is recommended and what’s the impact on the output file.
Because visually, both version look very similar on my gopro outdoor test file…
And I definitely prefer a smaller size of course…
Maybe a better documentation/help regarding the impacts of “Parallel processing” inside the GUI could be helpful? Same for hardware encoder.