fftest.sh

#!/bin/sh

#FLAGS="-hide_banner -loglevel error "
FLAGS="-hide_banner -loglevel warning "

echo === 128 AMD ====
vainfo --display drm --device /dev/dri/renderD128 | head -n3

# produces 5240 kb/s on  Linux 5.2.9  ffmpeg-4.2-4  libva-mesa-driver-19.1.5-1 (3.9.2019)
time ffmpeg $FLAGS -vaapi_device /dev/dri/renderD128 -i big_buck_bunny_720p_1mb.mp4 -vf 'format=nv12,hwupload' -c:v hevc_vaapi -b:v 5M -y new_bunny_128.mp4

echo === 129 Intel ===
vainfo --display drm --device /dev/dri/renderD129 | head -n3

# produces 76 kb/s on  Linux 5.2.9  ffmpeg-4.2-4  libva-mesa-driver-19.1.5-1 (3.9.2019)
#time ffmpeg $FLAGS -vaapi_device /dev/dri/renderD129 -i big_buck_bunny_720p_1mb.mp4 -vf 'format=nv12,hwupload' -c:v hevc_vaapi -b:v 5M -y new_bunny_129.mp4

# produces 5265 kb/s
#time ffmpeg $FLAGS -vaapi_device /dev/dri/renderD129 -i big_buck_bunny_720p_1mb.mp4 -vf 'format=nv12,hwupload' -c:v hevc_vaapi -b:v 5M  -rc_mode:v CBR -y new_bunny_129.mp4

# produces 4830 kb/s (= if VBR is is used, bitrate must be set but maxrate as well!)
time ffmpeg $FLAGS -vaapi_device /dev/dri/renderD129 -i big_buck_bunny_720p_1mb.mp4 -vf 'format=nv12,hwupload' -c:v hevc_vaapi -b:v 5M -maxrate:v 5M  -rc_mode:v VBR -y new_bunny_129.mp4

ls -lh new_bunny_*