[FFmpeg-user] GPU is not used

[Alexander Rodionov]

Im using ffmpeg to render video. Im saving images using matplotlib in format = rgba and pipe bytes to ffmpeg. 
If I open GPU usage - it shows 0% for ffmpeg process.

ffmpeg \
-loglevel debug \
-hwaccel videotoolbox \
-threads 16 \
-y \
-r 60 \
-s 1920x1080 \
-pix_fmt argb \
-i - \
-c:v hevc_videotoolbox \
-pix_fmt yuv420p \
-b:v 16M \
out.mp4

macOS Catalina 10.15.4
MacBook Pro (16-inch, 2019)
GPU: AMD Radeon Pro 5500M