ID attribute

All AdaptationSet, Representation, and Preselection elements within the one period should be uniquely identifiable by the id attribute.

Within the same period, AdaptationSet elements and Preselection elements must not have identical IDs. In addition, it is recommended that Representation elements have different IDs from the AdaptationSet elements and Preselection elements.

Although the MPEG‑DASH specification allows any string to be used as an element ID, for compatibility with ATSC A/344, the id attribute value must be an unsigned integer.