overlay.sh

FRAME_COUNT=$(ffprobe -v error -count_frames -select_streams v:0 \
  -show_entries stream=nb_read_frames -of default=nokey=1:noprint_wrappers=1 \
  "$INPUT")

FPS=$(ffprobe -v error -select_streams v -of default=noprint_wrappers=1:nokey=1 -show_entries stream=r_frame_rate "$INPUT")

ffmpeg -y \
	-r "$FPS" -i "$INPUT" \
	-loop 1 -r "$FPS" -i "$WATERMARK" \
	-filter_complex \
	"[1:v][0:v]scale2ref[logo][video]; \
	 [video][logo]overlay=:x=0:y=0:enable='eq(n,${FRAME_COUNT}-1):eof_action=pass'" \
	-shortest "${OUTPUT_VIDEO}"