Add a watermark image overlay
video filters
// what it does
With two inputs, `-filter_complex "overlay=W-w-10:H-h-10"` composites the second file (watermark.png) onto the first (the video). `W`/`H` are the base video's dimensions and `w`/`h` are the overlay's, so `W-w-10:H-h-10` anchors the logo to the bottom-right corner with a 10px margin. overlay respects the PNG's alpha channel, so a transparent logo blends rather than sitting in a box.
// shell
$ ffmpeg -i input.mp4 -i watermark.png -filter_complex "overlay=W-w-10:H-h-10" output.mp4// gotcha
Input order is load-bearing: the first `-i` is the base and the second is the overlay — swap them and you composite the video onto a single-frame image, so the output follows the still and truncates to one frame.