Crop 4k to HD centre

ffmpeg  -loglevel verbose \
-i $1 \
-ss 17.5 \
-t 16.5 \
-c:a aac \
-vbr 5 \
-c:v libx264 \
-crf 0 \
-coder 1 \
-context 1 \
-g 1 \
-threads 8 \
-vf 'crop=1920:1080:960:540' \
-y \
-r 30000/1001 \
$2