Interesting results. May I ask what was the original source video? 1080p,4k? 8bit, 10bit?It's absurdly fast.
My i9 iMac hovers just under 90 fps at HEVC with VideoToolbox. The M1 does 240fps at HEVC.
The M1 also supports constant quality encodes which is the first device to do so with VTB. The quality is less than Intel Quick Sync based VTB at fixed encodes though.