gistfile1.rb

#!/usr/bin/env ruby

def main
  source = ARGV[0]
  offset_time = ARGV[1].to_f
  trim_time = ARGV[2].to_f
  #size = '480x270'
  size = ARGV[3] 
  crop = ''
  crop = "-crop #{ARGV[4]}" unless ARGV[4].nil?
  loop = true
  frames = (trim_time * 30).to_i

  `ffmpeg -t #{trim_time} -ss #{offset_time} -i #{source} -an -vframes #{frames} %04d.png`
  if loop
    (1..(frames)).each do |i|
      copy_to = frames * 2 - i + 1
      `cp #{sprintf("%04d", i)}.png #{sprintf("%04d", copy_to)}.png`
    end
  end
#  `gm convert -delay 3.33 -loop 0 -crop "900x600+200+0" +repage -resize 450x300 *.png #{source}.gif`
  `gm convert -delay 3.33 -loop 0 #{crop} +repage -resize #{size} *.png #{source}.gif`
  `rm *.png`
  `~/workspaces/gifsicle-1.82.1-lossy/mac/gifsicle -O3 --colors 256 --lossy=100 -o #{source}_comp.gif #{source}.gif`
end
main

./mp42gif shirobako18.mp4 685.1 1.7