DASH-specific preprocessing requirements

There are specific requirements that apply to incorporating watermarking with DASH-format media.

At this time, the only variant of DASH that is supported is SegmentTemplate using the $Number$ expansion in a DASH media presentation description (MPD). The $Number$ macro must be at the end of the filename, and prefixed with an underscore ("_") character. Additionally, any “init” URLs must be prefixed with an additional naming of the form, “<filename>_init.mp4.” This helps Akamai detect the file as an “init” request and tells the Edge server to skip the AB switching.

The following DASH MPD snippet shows an example of the tags and attributes:

<MPD>
  <Period>
      <AdaptationSet mimeType="video/mp4" contentType="video">
          <SegmentTemplate duration="120" timescale="30" startNumber="1"
                           media="$RepresentationID$/$RepresentationID$_$Number$.m4v"
                           initialization="$RepresentationID$/$RepresentationID$_init.m4v"/>
          ...
      </AdaptationSet>
      <AdaptationSet mimeType="audio/mp4" contentType="audio">
          <SegmentTemplate duration="192512" timescale="48000" startNumber="1"
                           media="$RepresentationID$/$RepresentationID$_$Number$.m4a"
                           initialization="$RepresentationID$/$RepresentationID$_init.m4a"/>
          ...
      </AdaptationSet>
  </Period>
</MPD>