Profiles

A profile imposes a set of specific restrictions, which are typically on features of the MPD files and segment formats.

The profiles are signaled by the profiles attribute of the root XML element by one of the following URNs.
  • urn:mpeg:dash:profile:isoff-on-demand:2011

    ISO base media file format on-demand profile

  • urn:mpeg:dash:profile:isoff-live:2011

    ISO base media file format live profile

  • urn:mpeg:dash:profile:isoff-broadcast:2015

    ISO base media file format broadcast TV profile

Additionally, to indicate compatibility with different application specifications, the profiles attribute of the root XML element might contain one of the following URNs.
  • urn:dvb:dash:profile:dvb-dash:2014

    2014 edition of the DVB-DASH profile

  • urn:dvb:dash:profile:dvb-dash:2017

    2017 edition of the DVB-DASH profile

  • urn:hbbtv:dash:profile:isoff-live:2012

    HbbTV 1.5 DASH profile

  • http://dashif.org/guidelines/dash-atsc-main

    Main DASH interoperability point for ATSC

Multiple profiles can be simultaneously specified by providing multiple URNs as a comma-separated list to the profiles attribute.

Profiles for OTT applications

For OTT applications, the ISO base media file format on-demand and live profiles are commonly used.

For OTT content, it is anticipated that, for efficiency reasons, each experience is delivered on demand individually. Thus, for OTT delivery, a Dolby AC-4 bitstream ideally contains just one presentation.

Profile for broadcast and multicast applications

To meet the requirements for DASH delivery over multicast (for example, in a one-to-many, unidirectional way) and ATSC 3.0 broadcast, the ISO base media file format broadcast TV profile is defined. For more efficient bandwidth usage, it is recommended that Dolby AC-4 bitstreams are generated to contain all available audio components in one single elementary stream. One or multiple presentations in the Dolby AC-4 stream use combinations of the available components to provide a given number of audio experiences a user can choose from. To adequately signal these presentations in MPD, the preselection element is defined as part of the new profile.