FFmpeg Pad Filter: Letterbox and Pillarbox Video for Any Aspect Ratio

FFmpeg's pad filter adds black or colored bars to videos to fit any target aspect ratio without distorting the image. The command combines scale and pad filters to first resize the video while preserving aspect ratio, then center it on a canvas of the desired dimensions. Examples include recipes for 16:9, 9:16, and 1:1 outputs, with options for custom bar colors.