Tutorial: Cómo agregar videos de YouTube en los comentarios de Blogger

<script src='http://code.jquery.com/jquery-latest.js' type='text/javascript'/>
<script type='text/javascript'>
//<![CDATA[
// if oetag=0, just use video urls like:
//           http://www.youtube.com/watch?v=12345678901
//           surrounded by white space (video tag can be used, too)
// if oetag=1 (for nerdy blogs?), use syntax:
//           [video=http://www.youtube.com/watch?v=12345678901]
// config:
var oetag = 0;           // see above
var oetagname = "video"; // [video=zzz], maybe you like "embed" or "youtube" more?
var oelazy = -1; // -1 detect, 0 = normal, 1 = lazy (needs lazy load hack)
//
function oe_loadscript(filename) {
  var scr=document.createElement('script');
  scr.setAttribute("type","text/javascript");
  scr.setAttribute("src",filename);
  document.getElementsByTagName("head")[0].appendChild(scr);
}
function oe_jumptohash() { // reposition to anchor
  window.scrollTo(0, $("#"+window.location.hash.replace(/^#/, "")).offset().top);
}
var oe_tid;
var oe_elems = {};
//
function oembed_callback(response) {
  var resp = response;
  revurl = resp.url.split("").reverse().join("");
  html = oe_elems[response.callID].html();
  ee = $(resp.html);
  w = parseInt(ee.attr("width"));
  h = parseInt(ee.attr("height"));
  if(oelazy==1) { // convert to lazy load
    src = ee.attr("src");
    src += ((src.indexOf("?")==-1) ? "?" : "&") + "autoplay=1";
    ee.attr("src", src);
    ee.attr("style", "vertical-align:top;");
    htm = $("<div/>").append(ee).html();
    htm = $('<div/>').text(htm).html().replace(/"/g,'&quot;');
    resp.html = '<a href="'+resp.url+'" class="youtube-lazy-link" style="width: '+w+'px; height: '+h+'px; background: #000 url('+resp.thumbnail_url+') center center no-repeat;" onclick="$(this).replaceWith(\''+htm+'\');return false;"><div style="width:'+(w-4)+'px;height:'+(h-4)+'px;" class="youtube-lazy-link-div"></div><div class="youtube-lazy-link-info"><b>'+resp.title+(resp.playlist ? '</b> [playlist]' : '</b>')+'<br /><small>by '+resp.author_name+'</small></div></a>';
  }
  htmlx = html.replace("[" + oetagname + "="+resp.url+"]", " " + resp.url + " ");
  htmlx = htmlx.replace("[" + oetagname + "="+resp.url+" ]", " " + resp.url + " ");
  htmlx = htmlx.replace('"'+resp.url+'"', '"'+revurl+'"');  // trick to preserve href="url"
  htmlx = htmlx.replace(resp.url, '<div style="height:'+h+'px;" class="oembed youtube">'+resp.html+'</div>')
  htmlx = htmlx.replace('"'+revurl+'"', '"'+resp.url+'"');  // trick to preserve href="url"
  if(html != htmlx) {
    oe_elems[response.callID].html(htmlx);
    if(window.location.hash.replace(/^#/, "").length > 0) {
      if(oe_tid) window.clearTimeout(oe_tid);
      oe_tid = window.setTimeout("oe_jumptohash()", 1000);
    }
  }
}
function oembed_yt(url, width, callID) {
  src = "http://oembed-js.appspot.com/?url=" + encodeURIComponent(url) + "&callback=oembed_callback&callID=" + encodeURIComponent(callID);
  if(width) src = src + "&maxwidth=" + width + "&maxheight=" + width;
  oe_loadscript(src);
}
$(document).ready(function() {
 det=$('<div class="youtube-lazy-link-div" />');
 $("body").append(det);
 if(det.css("position")=="absolute") {
  if(oelazy != 0) oelazy=1;
 }
 else oelazy = 0;
 det.remove();
 window.setTimeout(function() {
  var callID=0;
  $(".comment-content,.comment-body,.comment-body-author").each(function() {
    html = " " + $(this).html() + " ";
    if(oetag)
      matches = html.match(new RegExp("\\["+oetagname+"=(https?:\\/\\/[^\\s<\\/]*youtu\\.*be[^\\]]+)", "g"));
    else
      matches = html.match(/([>\s^]|\[\w+=)(https?:\/\/[^\s<\/]*youtu\.*be[^\s<\]]+)/g);
    if(matches && matches.length) {
      for(var i=0;i<matches.length;i++) {
        url = matches[i].match(/https?:\/\/[^\s<\/]*youtu\.*be[^\s<\]]+/);
        oe_elems[callID] = $(this);
        oembed_yt(url, $(this).width(), callID++);
      }
    }
  });
 }, 500);
});
//]]>
</script>