Getting YouTube download URLs for a given video ID

gistfile1.php

// fill in the video ID here
$video_id       = '';

$info_url       = 'http://www.youtube.com/get_video_info?video_id=' . $video_id;
$info_page      = file_get_contents($info_url);

// put query strings into local scope
parse_str($info_page);

// parse fmt_stream_map
$stream_map     = explode("|", $fmt_stream_map);

// select first stream URL
$yt_url         = urldecode($stream_map[1]);

// now you can do anything with $yt_url