converting a video to grayscale with ffmpeg

[NapoleonWils0n]

convert a video to grayscale

ffmpeg -i infile -filter:v "hue=s=0" outfile.mp4

cropping a video, converting to grayscale and padding

ffmpeg -i infile.mp4 -filter:v "crop=1440:1080:240:0,hue=s=0,pad=1920:ih:(ow-iw)/2" outfile.mp4

example of big buck bunny cropped, converted to grayscale and padded
then overlayed onto of Night of the living dead to mix the footage together