how to Direct download HQ MP4 videos from You Tube

first open the video you want to download click the hq tab under the video and then post this script

javascript:window.location.href%20=%20'http://youtube.com/get_video?video_id='%20+%20swfArgs['video_id']%20+%20"&fmt=18"%20+%20"&l="%20+%20swfArgs['l']%20+%20"&sk="%20+%20swfArgs['sk']%20+%20'&t='%20+%20swfArgs['t'];

on the address bar and then wait for the save video file and then voila! you have your HQ MP4 vid...:p