update_mp4_tag.rb

require 'rubygems'
require 'id3lib'

# Set file name
filename = ARGV[0]
exit unless FileTest.exists?(filename)

basename = File::basename(filename, '.mp3').scan(/.*_(.*)-(.*)/)
season = basename[0][0]
chapter = basename[0][1]

# Load a tag from a file
tag = ID3Lib::Tag.new(filename)
#p tag
#exit

# Set tag information
tag << { :id => :TPE1, :text => "FRIENDS" }
tag << { :id => :TALB, :text => "FRIENDS-#{season}" }
tag << { :id => :TIT2, :text => "FRIENDS_#{season}-#{chapter}" }
tag << { :id => :TRCK, :text => "#{chapter}/24" }
tag << { :id => :TCON, :text => "TV" }

# Add an attached picture frame
cover = {
  :id          => :APIC,
  :mimetype    => 'image/jpeg',
  :picturetype => 3,
  :description => '',
  :textenc     => 0,
  :data        => File.read("/Users/n0ts/Desktop/#{season}.jpg")
}
tag << cover

# Update tag information
tag.update!