title: MPEG-DASH - How is the content separated in AdaptationSet?
body: <p>I'm trying to understand the MPD format. I read the information about AdaptationSet in the standard, but I don't understand well how the separation of the Representations into different AdaptationSets is made.</p>
  
  <p>The standard points out:</p>
  
  <p><em>Representations are arranged into Adaptation Sets according to the media content component properties of the media content components present in the Representations, namely</em></p>
  
  <pre><code>the language as described by the @lang attribute, 
  the media component type described by the @contentType attribute, 
  the picture aspect ratio as described by the @par attribute, 
  the role property as described by the Role elements, 
  the accessibility property as described by the Accessibility elements, 
  the viewpoint property as described by the Viewpoint elements, 
  the rating property as described by the Rating elements.*
  </code></pre>
  
  <p>For example: <a href="http://www-itec.aau.at/~cmueller/libdashtest/showcases/redbull_segment_template.mpd" rel="nofollow">http://www-itec.aau.at/~cmueller/libdashtest/showcases/redbull_segment_template.mpd</a></p>
  
  <p>There are five AdaptationSets, I think the <strong>media component type (contentType)</strong> is video for all them, although I don't understand the value of the attribute <em>contentType="RedBull 320x240"</em>, <em>contentType="RedBull 480x360"</em>, etc. and the <strong>picture aspect ratio</strong> is equal for the first two adaptationSet and it is equal for the last three AdaptationSet. And for other mentioned properties(role, viewpoint, etc.), no information is provided.</p>
  
  <p>In another example: <a href="http://ftp-itec.uni-klu.ac.at/dash/conformance/mp4-full-gdr/mp4-full-gdr-mpd-AV-BS.mpd" rel="nofollow">http://ftp-itec.uni-klu.ac.at/dash/conformance/mp4-full-gdr/mp4-full-gdr-mpd-AV-BS.mpd</a>, the value of <strong>codecs</strong> is different for each representation into the same AdaptationSet. Therefore, this attribute doesn't affect to the separation in different AdaptationSet.</p>
  
  <p>Any help?</p>
  
  <p>Thank you!</p>