Quickly check for supported NVENC and NPP hardware acceleration capabilities in FFmpeg on your platform:
Depending on how you built ffmpeg, you may want to check the supported NVENC-based hardware acceleration capabilities in ffmpeg by running:
$ for i in encoders decoders filters; do
echo $i:; ffmpeg -hide_banner -${i} | egrep -i "npp|cuvid|nvenc|cuda|nvdec"
done
Sample output (as on my testbed):