Adaptation sets

An adaptation set describes the overall media presentation.

The media presentation typically consists of multiple instances of the same audio, video, or audio/video content, with each instance encoded at a different data rate. A representation describes the parameters of each individual encoding of an adaptation set:

• The codecs attribute is required. It specifies the codecs used to encode all representations within the adaptation set. For all Dolby Digital Plus bitstreams, the codecs attribute must include the entry ec-3^[1].

  For Dolby Digital Plus bitstreams that carry Dolby Atmos content, the corresponding representations must include additional SupplementalProperty descriptors.

• The mimeType attribute describes the encapsulation format used to store the Dolby Digital Plus bitstreams present in the adaptation set. For adaptation sets that conform to ISO/IEC 14496-12, the mimeType attribute must be set to audio/mp4 (for ISO base media files that contain a Dolby Digital Plus audio track but no accompanying video track).