Rendering a video with KDEnlive 22.08.1 under Ubuntu 22.04 on the Acer Nitro5 with the hardware accelerated VAAPI Intel H264 profile aborts with this error: Driver does not support any RC mode compatible with selected options (supported modes: CQP).
I’m not deep enough into the KDEnlive architecture to understand what I’m doing, my superficial understanding is that KDEnlive uses the MLT framework to do its rendering which generates this error. A quick search reveals that VAAPI can be configured with rc_mode parameter, so I created a new rendering profile with these parameters which worked:
f=mp4 vaapi_device=/dev/dri/renderD128 vf=’format=nv12,hwupload’ vcodec=h264_vaapi vb=30000k acodec=aac ab=192k channels=2 threads=0 rc_mode=CQP real_time=-1
George's Techblog 
I stumbled over the same issue today with my KDEnlive after finding the hardware accelerated rendering options for the first time. Thank you for sharing this fix/workaround. 🙂
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‘Thanks so much for this, I was pulling my hair out. I’ve gone from 1fps on a 4k render to 8fps.
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