Home
Media Presentation Description with Dolby AC-4 Use proper values in an MPD file to describe a Dolby AC-4 bitstream. Examples of MPD files for different scenarios are provided.
Media Presentation Description file examplesExample MPD files for different media presentations are provided.
Media Presentation Description with a single audio componentThis MPD example consists of one audio adaptation set with a 5.1.2 channel-based immersive Dolby AC-4 representation.

Introduction to the Dolby AC-4 in MPEG-DASH for online delivery specificationThis documentation is for online delivery (over-the-top services), specifying the required data formatting and signaling between a server (sender) and clients (receivers) to enable Dolby AC-4 to be used as an audio format within the MPEG‑DASH standard in conjunction with the ISO base media file format.
Dolby AC-4 packetization into MPEG-DASH compliant ISO base media files The process of analyzing and preparing a Dolby AC-4 bitstream for storage within an MPEG-DASH compliant ISO base media file is described. AC-4 sync frames must be converted to raw AC-4 frames before packetization.
Media Presentation Description with Dolby AC-4 Use proper values in an MPD file to describe a Dolby AC-4 bitstream. Examples of MPD files for different scenarios are provided.
- Media Presentation Description An MPD can be used to describe media presentations with one or multiple Dolby AC-4 bitstreams.
- ProfilesA profile imposes a set of specific restrictions, which are typically on features of the MPD files and segment formats.
- PeriodsMedia content can be composed of a single period or multiple consecutive media content periods.
- Adaptation sets and representationsAn adaptation set typically consists of multiple representations of the same audio, video, or A/V content. Each representation is associated with a Representation element.
- AudioChannelConfiguration descriptorThe channel configuration for a Dolby AC-4 stream is specified in the AudioChannelConfiguration descriptor.
- Accessibility descriptorThe Accessibility descriptor indicates the presence of accessibility features such as AD, visual description service, or dialogue enhancement.
- MPD for immersive stereo contentTo signal immersive stereo content in the MPD file, an additional SupplementalProperty descriptor must be included.
- ATSC 3.0 specific constraints on Media Presentation Description MPD files for ATSC 3.0 services must adhere to the constraints defined in DASH-IF Interoperability for ATSC 3.0 and the Broadcast TV Profile constraints from ISO/IEC 23009-1.
- Compatibility with ATSC 3.0 and DVB-DASHTo be compatible with ATSC 3.0 and DVB-DASH, required settings must be used for the AudioChannelConfiguration descriptor and the Accessibility descriptor.
- Media Presentation Description file examplesExample MPD files for different media presentations are provided.
  - Media Presentation Description for a single video component and single audio componentThis MPD example describes a simple media presentation that consists of a single video component with a single 5.1-channel (L, C, R, Ls, Rs, LFE) Dolby AC-4 audio component. Three representations of the video content and three representations of the audio content are provided, each at a different data rate.
  - Media Presentation Description for a single video component and an immersive stereo audio componentThis MPD example consists of two adaptation sets. One adaptation set contains an H.264 video representation, and the other one contains a 2.0-channel immersive stereo audio representation.
  - Media Presentation Description with multiple adaptation setsThis MPD example consists of three adaptation sets. The first one is a video adaptation set containing an H.264 video representation. The other two are audio adaptation sets, one containing a 2.0-channel Dolby AC-4 audio representation, and one containing a 5.1-channel Dolby AC-4 audio representation.
  - Media Presentation Description with a single audio componentThis MPD example consists of one audio adaptation set with a 5.1.2 channel-based immersive Dolby AC-4 representation.
Demultiplexing a Dolby AC-4 bitstream from an MPEG-DASH compliant ISO base media file segmentBuffering and parameter conflicts must be considered when product designers implement an ISO base media file format file demultiplexer that supports Dolby AC-4 bitstreams.
MPEG‑DASH and Dolby AC-4 overviewIntroduction about MPEG‑DASH and Dolby AC-4.
Glossary
Notices

Media Presentation Description with a single audio component

This MPD example consists of one audio adaptation set with a 5.1.2 channel-based immersive Dolby AC-4 representation.

<?xml version="1.0"?>
<MPD
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:dolby="http://www.dolby.com/ns/online/DASH"
  xmlns="urn:mpeg:dash:schema:mpd:2011"
  xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 DASH-MPD.xsd"
  profiles="urn:mpeg:dash:profile:isoff-broadcast:2015"
  type="dynamic">
  <Period>
    <AdaptationSet id="1" mimeType="audio/mp4" codecs="ac-4.02.01.02" lang="en" segmentAlignment="true" startWithSAP="1">
      <Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"/>
       <SegmentTemplate timescale="48000" media="audio_singlepres_512cm/$Time$.m4s" initialization="audio_singlepres_512cm/init.mp4">
        <SegmentTimeline>
          <S t="0" d="96000" r="36"/>
        </SegmentTimeline>
      </SegmentTemplate>
      <Representation id="r1" audioSamplingRate="48000" bandwidth="160000">
        <AudioChannelConfiguration schemeIdUri="tag:dolby.com,2015:dash:audio_channel_configuration:2015" value="0000C7"/>
      </Representation>
   </AdaptationSet>
    </Period>
</MPD>