Source for "Download YouTube Videos as MP4"

By gantt
Has 1 other script. 

// ==UserScript==
// @name           Download YouTube Videos as MP4
// @description    Adds an option to download YouTube videos.
// @namespace      http://googlesystem.blogspot.com
// @include        http://*.youtube.com/watch?*
// @include        http://youtube.com/watch?*
// @version        0.5
// ==/UserScript==

(function () {

  if (document.getElementById('download-youtube-video')) return;

  var video_id = null;
  var video_hash = null;
  var video_player = document.getElementById('movie_player');
  
  if (video_player) {
    var flash_variables = video_player.attributes.getNamedItem('flashvars');  
    if (flash_variables) {
      var flash_values = flash_variables.value;
      if (flash_values) {
        var video_id_match = flash_values.match(/video_id=([^(\&|$)]*)/);
        if (video_id_match!=null) video_id = video_id_match[1];
        var video_hash_match = flash_values.match(/t=([^(\&|$)]*)/);
        if (video_hash_match!=null) video_hash = video_hash_match[1];        
      }
    }
  }
  
  if (video_id==null || video_hash==null) {
    var args = unsafeWindow.swfArgs;
    if (args) {
      video_id = args['video_id'];
      video_hash = args['t'];  
    }
  }
  
  if (video_id==null || video_hash==null) return;
 
   var yt_mp4_path ='http://www.youtube.com/get_video?fmt=18&video_id='+video_id+'&t='+video_hash; 
   var div_embed = document.getElementById('watch-embed-div');
   if (div_embed) {      
     var div_download = document.createElement('div');
     div_download.innerHTML = '<br /> <span id=\'download-youtube-video\'> <a href=\''+yt_mp4_path+'\'>Download as MP4</a> '+ ((navigator.userAgent.indexOf('Safari')!=-1)?'(control-click and select <i>Download linked file as</i>)' : ('(right-click and select <i>Save '+ (navigator.appName=='Microsoft Internet Explorer'?'target':'link') +' as</i>)')) + '</span>';
     div_embed.appendChild(div_download);
  }
  
})();