[FFmpeg-user] Minimize CPU use with QuickSync?

Jason Coleman pobox at chiencorp.com
Thu Jun 28 23:49:01 EEST 2018


I recently picked up a computer with a Kaby Lake processesor, and I'm trying to setup ffmpeg transcodes to minimize impact to the CPU and maximize use of QuickSync during transcodes. I am going by indirect indicators (CPU use and GPU use, as indicated in the Windows 10 task manager) + what ffmpeg output says. I thought I had the entire pipeline (decode/scale-resize/encode) being performed by Quicksync, but I'm still getting a lot of CPU use, call it 70-90%. Maybe my expectations are out of line and I need to adjust those? Am I missing anything that would cause operations to happen on the CPU instead? I'm currently using a zeranoe 64 bit build, on Win10 home, with the current Intel drivers. So this is an example encoding line, I don't have an output from ffmpeg in front of me, apologies, I can put one up later:

C:\ffmpeg\ffmpeg.exe -hwaccel qsv -init_hw_device qsv=qsv:MFX_IMPL_hw_any -filter_hw_device qsv -i "testvid.mp4" -vf "format=nv12,hwupload=extra_hw_frames=100,scale_qsv=640:360" -b:v 800k -c:v h264_qsv -c:a copy -y "testoutput.mp4"

Thank you!


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