title: Find the playlists a video is in via Youtube API
body: <p>I want to know which playlists contain a certain video. The opposite is easy: find which video's are in a playlist, but I don't want that.</p>
  
  <p>I can already have YT do this via the following route, but that's stupid and slow:</p>
  
  <ul>
  <li>get channelId from video data (<code>videos?id=...</code>)</li>
  <li>get playlists from channelId (<code>playlists?channelId=...</code>)</li>
  <li>loop through all playlists and find all their videos (<code>playlistItems?playlistId=...</code>)</li>
  </ul>
  
  <p>Like I said: stupid and slow. These steps are possible, because I only want playlists authored by the video's author. (Otherwise I'd have to download all of YT.)</p>
  
  <p>What I'm looking for, sort of, is a request: <code>playlists?videoId=...</code>, but of course that doesn't exist.</p>
  
  <p>Is there a better way than my 3 steps?</p>
  
  <p>PS. I've created <a href="http://public.home.hotblocks.nl/yt.js" rel="nofollow">the script to use my 3 steps</a>, but it's A LOT of requests. That and the playlists don't seem to have usable playlist ID's... I need the ID that the browser uses to show the playlist GUI style.</p>