title: MPEG-4 Part 2 had some awesome face- and body- motion concepts, but they disappeared in MPEG-4 Part 10 (H.264). Why?
body: <p>During the last few weeks, I had the opportunity to read two documents:</p>
  
  <ul>
  <li>The MPEG-4 Part 2 specification (ISO/IEC 14496-2), which people just call "mpeg-4"</li>
  <li>The MPEG-4 Part 10 specification (ISO/IEC 14496-10), which is also called "h.264" or "AVC"</li>
  </ul>
  
  <p>After having read all the cool ideas in "mpeg-4" like identifying facial expression, motion of limbs of people, and sprites, I got really excited. The ideas sound very fun, maybe even fantastic, for an idea from 1999.</p>
  
  <p>But then I read the "h.264" standard, and none of those ideas were there. There was a lot of discussion on how to encode pixels, but none of the really cool ideas.</p>
  
  <p>What happened? Why were these ideas removed?</p>
  
  <p>This is not a code question, but as a programmer I feel I should attempt to understand as much of the <em>intent</em> behind a specification. If the code I write adheres to the spirit in which the specification was meant to be used, it's more likely to be positioned to take advantage of the entire specification.</p>