Thumbnails generator script using VLC.

vlc_gen_thumbnails.sh

#!/bin/bash

VLC="vlc -I dummy"
TARGET_DIR="movies"
THUMBNAIL_DIR="movies/thumbnails"
THUMBNAIL_FMT="jpg"

set -eux

gen_options() {
  local options=''
  while read target; do
    filename=`basename $target`;
    filename=${filename%.*};
    options="$options $target \
      --rate=1 \
      --video-filter=scene \
      --vout=dummy \
      --start-time=10 \
      --stop-time=11 \
      --scene-format=$THUMBNAIL_FMT \
      --scene-ratio=24 \
      --scene-prefix=${filename}_ \
      --scene-path=$THUMBNAIL_DIR"
  done
  echo $options
  return 0
}

$VLC `find $TARGET_DIR -mindepth 1 -type f | gen_options` "vlc://quit"