If I reboot PC without monitor to be connected (like on server) and run command over shh then I get less fps (converting speed).
Build with instructions: https://gist.github.com/Brainiarc7/4f831867f8e55d35cbcb527e15f9f116
Tested on i7- 6700 and on i7- 8700 CPU on Ubuntu 18.04 with ffmpeg with same result -> no monitor-> less fps.
ffmpeg -hwaccel qsv -c:v h264_qsv -i 720p.mp4 -c:v h264_qsv -preset 7 -b:v 6M -vf scale_qsv=1920:1080 -an -y h264.mp4
Monitor connected : fps: 330fps
Monitor not connected: 250fps
Then I check GPU clock via "sudo intel_gpu_frequency" it jump to max 1200 MHz.
Than I try to create watermark on video:
ffmpeg -hwaccel qsv -c:v h264_qsv -i 720p.mp4 -c:v hevc_qsv -preset 7 -filter_complex "scale_qsv=1920:1080[s2];movie=watermark.png,scale=1080*0.75:-1,format=nv12,hwupload=extra_hw_frames=30[watermark];[s2][watermark]overlay_qsv=(main_w-overlay_w)/2:(main_h-overlay_h-10)/1:alpha=150[overlay]" -map [overlay] -map a? -c:a copy -b:v 6M -y out_watermark.mp4
Monitor connected : fps: 300fps
Monitor not connected: 200fps
Any idea why up to 30% less without monitor with overlay_qsv filter?
