title: Media Foundation. Encoding video from bitmaps with custom IMFMediaSource
body: <p>Can anyone clarify the following questions? A decent source code snippet or example would be wonderful, the only relevant example I've found so far is WavSource in the SDK.</p>
  
  <ol>
  <li><p>How is the raw bitmap data presented to the encoder? Is it (A)RGB 32BPP or similar?</p></li>
  <li><p>On the basis of the WavSource sample something calls RequestSample() on the input stream, this returns data, play time and duration. So I'd be returning a suitably formatted buffer with a playtime and a duration of 1s?</p></li>
  </ol>
  
  <p>Thanks.</p>