Generate video thumbnails at 15 sec timestamp from directory of MP4 files

genthumbs.sh

#!/bin/bash

for i in *.mp4; do
  [[ $i == *"- clean"* ]] && continue # this line excludes files that contain "- clean" in filename
  prefix=`echo "$i" | sed "s/^\([0-9]*\)\.\(.*\)/\1/"`;
  ffmpeg -i "$i" -ss 00:00:15.00 -vf "thumbnail,scale=480:270" -frames:v 1 "$prefix.webp"
done