Video previewer. Outputs 10 evenly spaced frames for a directory of videos.

preview.rb

Dir.glob('/YOUR_VIDEOS/*.mp4') do |f|
  name = File.basename(f, ".*")
  len = `ffprobe #{f} -show_entries format=duration -v quiet -of csv="p=0"`
  for n in (1..10)
    l = len.to_f / 10 * n
    `ffmpeg -i #{f} -ss #{l} -v quiet -vframes 1 './preview/#{name}_#{n}.png'`
  end
end