extracts images from all video files in a directory using ffmpeg

extract-img.sh

# extract images from video file 
# sh extract-img.sh -e [extension] -fr [frame rate]

_ext=""
_fr=1
while getopts ":e:o:f:n:" opt; do
  case $opt in
    e) 
        _ext="$OPTARG"
        ;;
    f) 
        _fr="$OPTARG"
        ;;
    \?)
        echo "ERROR: Invalid option: -$OPTARG" >&2
        exit
        ;;
  esac
done

i=0
for file in *.$_ext; do
    ffmpeg -i $file -r $_fr output_"$i"_%04d.jpeg
    i=$((i+1))   
done