[FFmpeg-user] vaapi_h264 encoding very low bitrate

[owen s]

I am running this command with
ffmpeg -y -loglevel debug \
-vaapi_device /dev/dri/renderD128 \
-loop 1 -r 1 -i ./image.jpg -pix_fmt vaapi_vld \
-b:v 18000k -minrate 18000k \
-vf 'format=nv12|vaapi,hwupload,scale_vaapi=w=1280:h=720' \
-rc_mode 3 \
-r 30 -g 60 \
-c:v h264_vaapi -f flv /dev/null

I am getting high encoding speed of greater than 3x but the bitrate is
terrible 350Kbits/s

Why is that when I can get better encoding speeds using cpu? log file
http://0x0.st/-i2j.txt