title: Windows Phone 7 and MP4
body: <p>I installed all the needed tools and I wrote a simple YouTube downloader for WP7.
  The problem is with playing.. I tried several mp4 formats (listed here <a href="http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs" rel="nofollow">http://en.wikipedia.org/wiki/YouTube#Quality_and_codecs</a>) with that code:</p>
  
  <pre><code>    new MediaPlayerLauncher() {
          Media = new Uri("http://localhost/asd.mp4"),
          Controls = MediaPlaybackControls.All
      }.Show();
  </code></pre>
  
  <p>But every time it says "Playback error".
  I've read the WP7 codec support page (<a href="http://msdn.microsoft.com/en-us/library/ff462087%28VS.92%29.aspx" rel="nofollow">http://msdn.microsoft.com/en-us/library/ff462087%28VS.92%29.aspx</a>) and it has multiple mp4+aac supports.</p>
  
  <p>Question 1: Can WP7 run YouTube videos (formats from the first url)?</p>
  
  <p>Question 2: Will Microsoft accept my app for the Marketplace?</p>