Here's the command that'd add pillar- or letterboxing for a fixed output width. It's a tad long, but you'll have to specify the padding some way. First, in your shell define output width and height: width=700 height=400 Then run the command: ffmpeg -i in.mp4 -filter:v "scale=iw*min($width/iw\,$height/ih):ih*min($width/iw\,$height/ih), pad=$width:$height:($width-iw*min($width/iw\,$height/ih))/2:($height-ih*min($width/iw\,$height/ih))/2" out.mp4 This is stripped down to the bare essentials needed to resize and pad—add your other video and audio options as you see fit.