Convert Youtube Caption to SRT.

convert.rb

#coding:utf-8
require 'xmlsimple'
require 'time'

def generate_time f
  hour = (f/60/60).to_i
  f += -(hour*60*60)
  min = (f/60).to_i
  f += -(min*60)
  sec = f.to_i
  float = ((f-sec)*1000).to_i
  "#{pad hour}:#{pad min}:#{pad sec},#{float}"
end

def pad i
  i = i.to_i
  if i < 10
    "0#{i}"
  else
    i.to_s
  end
end
xml = XmlSimple.xml_in(open(ARGV[0]).read)
srt = ''
xml['text'].each_with_index{|x,i|
  start = x['start'].to_f
  from = generate_time x['start'].to_f
  to = generate_time x['start'].to_f + x['dur'].to_f
  srt += <<EOS
#{i+1}
#{from} --> #{to}
#{x['content']}

EOS

}
puts srt

Usage:
ruby convert #{Youtube Caption's XML} > foobar.srt