Authentication and authorization of a client are key enablers of establishing trust in a client (e.g., a player). This is needed to ensure only clients that obey a specific set of requirements (e.g. ones imposed by advertisers or MVPDs) have access to content.
MPD linking allows pointing to media components in other MPDs to provide a relation, such that seamless transition between such MPDs is possible. A specific example is mosaic channels in combination with Spatial Relation Description as defined in the ISO/IEC 23009-1:2014 Amd.2.
The callback event is considered relevant for different use cases, including consumption and ad tracking.
Period continuity enables to break content into multiple Periods, but provides a seamless playout across Period boundaries. This is relevant for use cases such as providing robust live services and ad insertion.