On Linux using ffmpeg:
Code:
for f in *.*; do ffmpeg -i "$f" -vf "movie=../watermark.png [watermark]; [in][watermark] overlay=main_w-overlay_w-5:main_h-overlay_h-5 [out]" -strict -2 -y out/"$f"; done
where 'watermark.png' is the image you want to use as a watermark. This will watermark everything in the current directory on the bottom right corner. Also create a directory named 'out' under this directory and it will put the watermarked files there.
