<smil>
  <head>
    <switch>
      <layout>
         <region id="test" top="0" left="0" height="100" width="100" />
      </layout>
      <layout type="text/other">
         sadjasdf;jasdfj
      </layout>
    </switch>
  </head>
  <body>
    <img src="http://smil.nist.gov/interop1/getout.jpg"
         region="test"
    />
  </body>
</smil>