This is a script that helps you download any apple keynote presentation on http://www.apple.com/apple-events/. You can copy any of the keynote broadcast link, pick a resolution and feed to this script, this script will help you download the stream video.

down_video.rb

#!/usr/bin/env ruby 
# 
#  Name: Apple keynote stream video downloader
#  Author: venj<i[AT]venj.me>
#  Date: 2012-09-13
#
#  Description: 
#    This script helps you download apple keynote stream video on  
#    http://www.apple.com/apple-events/. Video format is TS. 
#    
#    This script uses many dirty code to make it possible to download
#    all the videos that is currently available on that URL. 
# 
#    This script tried its best to be future proof (and it proves!),  
#    but Apple changes the stream video file format frequently, so it 
#    may not be able to download future keynotes. But I will update 
#    this script if any change happens.
#
#  How to use: 
#    ./down_video resolution broadcast_link
#
#  Example: 
#    ./down_video 720p http://www.apple.com/apple-events/education-january-2012/
#  
#  Update Notes:
#  2012-09-13 Added support for download September 2012 apple event.
#             Now show a nicer fragment count while downloading.
#  2012-03-08 Fixed a bug that will cause open-uri error under Ruby 1.8.7
#  2012-03-08 Update resolution fields, for 3 different size 720 sized video(no 1080).
#  2012-02-07 First script that can download all apple keynotes stream video finished.
#

require "open-uri"

resolution = ARGV[0]
weblink = ARGV[1]

size_arr = ["720p", "720", "720i", "540p", "540i", "360p", "360", "360i", "224p", "224i"]
size_hash = {"720p" => "6540", "720" => "4540", "720i" => "3340", "540p" => "2540", "540i" => "1840", "360p" => "1240", "360" => "0640", "360i" => "0440", "224p" => "0240", "224i" => "0150"}

if ["--help", "help", "-h"].include?(resolution) || ARGV.size < 2
  puts "Usage: #{File.basename __FILE__} resolution broadcast_link"
  puts "\nPossible resolution values: \n\t#{size_arr.join(', ')}"
  exit 0
end

unless size_arr.include?(resolution)
  puts "Usage: #{File.basename __FILE__} resolution broadcast_link"
  puts "\nPossible resolution values: \n\t#{size_arr.join(', ')}"
  exit 0
end

m3u_link = ""

puts "Parsing webpage..."
#puts open(weblink).read
#exit
begin
  m3u_link = open(weblink).read.match(/http:\/\/.+?\.m3u8/)[0]
rescue NoMethodError => e
  begin # Handles 1 possible javascript redirection.
    redirect_link = open(weblink).read.match(/http:\/\/.+?\.html/)[0]
    m3u_link = open(redirect_link).read.match(/http:\/\/.+?\.m3u8/)[0]
  rescue NoMethodError => e
    begin
      urljs = open(weblink).read.match(/http:\/\/.+?\/url\.js/)[0] # For september-2012 event.
      m3u_link = open(urljs).read.match(/http:\/\/.+?\.m3u8/)[0]
    rescue Exception => e
      puts "No video found."
      exit 1
    end
  end
rescue Exception => e
    puts "Unknown error."
    exit 1
end

playlist_links = []

puts "Parsing outter m3u8 file..."
m3u = open(m3u_link).each_line do |line|
  playlist_links << line if line =~ /^[^#]/ && line.strip != ""
end

available_resolutions = []
playlist_links.each do |l|
  rate = ""
  segments_count = l.split("/").size
  case segments_count # A dirty way to identify different m3u8 link structure
  when 6 # Modern format with full link
    rate = File.basename(File.dirname(l))
  when 5 # Previous format with full link
    rate = l.split("/").last.split(".").first
    if !size_hash.values.include?(rate)
      rate = File.basename(l).split("_").first
    end
  when 1 # Previous format with only file name.
    rate = l.split(/(\.|_)/).first
  else
    puts "Unknown outter m3u8 format. \n\nPlease file a bug with failed link."
    exit 1
  end
  available_resolutions << (size_hash.invert)[rate]
end

unless available_resolutions.include?(resolution) 
  puts "Resolution #{resolution} is not available."
  # Ignore the audio track in one particular case: apple-events/september-2010. 
  puts "Available resolutions: #{available_resolutions.compact.sort.join(', ')}"
  exit
end

puts "Parsing inner m3u8 file..."
link_index = available_resolutions.index(resolution)
outfilename = "video_#{resolution}.ts"
File.unlink outfilename if File.exists? outfilename

video_url = playlist_links[link_index]
unless video_url =~ /^http/ # Handles inner m3u8 with only filename listed in outter m3u8
  video_url = "#{File.dirname(m3u_link)}/#{video_url}"
end
outfile = open outfilename, 'w+'

ts_fragments_list = []
open(video_url).each_line do |line|
  next if line =~ /^#/
  ts_fragments_list << line
end

counter = 1;fragments_count = ts_fragments_list.size
ts_fragments_list.each do |line|
  ts_fragment = ""
  if line.include?("http://")
    ts_fragment = line
  else
    ts_fragment = "#{File.dirname(video_url)}/#{line.strip}"
  end
  print "Download fragment (#{counter}/#{fragments_count})..."
  infile = open ts_fragment
  outfile.write infile.read
  infile.close
  counter += 1
  puts "Done"
end
outfile.close