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Dolby Digital Plus and HTTP Live StreamingThis section specifies the required data formatting and signaling between the server (sender) and the clients (receivers) to use Dolby Digital Plus audio bitstreams in Apple HTTP Live Streaming audio/video (A/V) delivery applications.
HTTP Live Streaming playlist filesAn HTTP Live Streaming master playlist file provides information for your product about the available content for a media presentation.
Codec type indication for Dolby Atmos contentFor HTTP Live Streaming streams containing Dolby Digital Plus tracks with Dolby Atmos content, the CODEC attribute of the EXT-X-STREAM-INF parameter must include a value of ec-3 for indication of the audio codec. In addition, a CHANNELS attribute must be included in the #EXT-X-MEDIA parameter.

IntroductionThis documentation supports the system designers and engineers who are building a content creation product. It lists the requirements for creating Dolby Digital Plus content in such a product and provides guidance to help in meeting the requirements.
Product overviewA typical product built and tested using the resources in this kit delivers Dolby Digital Plus content in an online container that supports adaptive streaming.
RequirementsAn online delivery content creation product must meet all defined requirements for the online delivery formats it supports.
Dolby Digital Plus streams in online delivery formatsThe Dolby Digital Plus format provides a high level of flexibility and can support complex bitstream configurations. To minimize impact on decoding devices while ensuring that a wide range of applications can be supported, some constraints are applied to the permitted bitstream structure and to bitstream parameter settings.
Dolby Digital Plus and MPEG-DASHThese topics provide guidance to assist you in meeting the requirements for delivering Dolby Digital Plus streams using the MPEG-DASH standard in conjunction with the ISO base media file format.
Dolby Digital Plus and HTTP Live StreamingThis section specifies the required data formatting and signaling between the server (sender) and the clients (receivers) to use Dolby Digital Plus audio bitstreams in Apple HTTP Live Streaming audio/video (A/V) delivery applications.
- HTTP Live Streaming transport stream segmentsGenerally, the HTTP Live Streaming application uses segmented MPEG-2 transport streams or fragmented MP4 files to deliver a multimedia presentation that contains both audio and video content. Apple recommends using the fragmented MP4 file solution.
- Dolby Digital Plus packetization into an MPEG-2 transport streamThis section describes the process of analyzing and preparing a Dolby Digital Plus bitstream for storage within an HTTP Live Streaming compliant MPEG-2 transport stream.
- MPEG-2 transport stream segment transition requirementsAt the transition point from one MPEG-2 transport stream segment to another, specific requirements must be followed to ensure that playback across the transition point continues seamlessly for both audio and video.
- Dolby Digital Plus packetization into an audio-only elementary stream Dolby Digital Plus bitstreams can be packetized into HTTP Live Streaming compliant audio-only elementary streams by using pack audio with the ID3 tag.
- Dolby Digital Plus packetization into a fragmented MP4 fileThe latest HTTP Live Streaming specification recommends using fragmented MP4 files for delivery of a multimedia presentation that contains both audio and video content, with audio and video content packetized in separate fragmented MP4 files. For details about Dolby Digital Plus packetization into an MP4 file, refer to Dolby Digital Plus and ISO base media file format.
- HTTP Live Streaming playlist filesAn HTTP Live Streaming master playlist file provides information for your product about the available content for a media presentation.
  - Codec type indication for Dolby Digital Plus For media streams containing Dolby Digital Plus, the CODEC attribute of the EXT-X-STREAM-INF parameter is recommended for codec type indication.
  - Codec type indication for Dolby Atmos contentFor HTTP Live Streaming streams containing Dolby Digital Plus tracks with Dolby Atmos content, the CODEC attribute of the EXT-X-STREAM-INF parameter must include a value of ec-3 for indication of the audio codec. In addition, a CHANNELS attribute must be included in the #EXT-X-MEDIA parameter.
  - Construction of the HTTP Live Streaming master playlist fileTo construct an HTTP Live Streaming master playlist file for a media presentation with multiple audio codecs (such as Dolby Digital Plus and AAC), use the #EXT-X parameters.
  - Examples of HTTP Live Streaming playlist files with Dolby Digital Plus This topic contains examples of HTTP Live Streaming playlist files with Dolby Digital Plus.
Dolby Digital Plus and ISO base media file formatThis section describes the process of analyzing and preparing a Dolby Digital Plus bitstream for online delivery within an ISO base media file.
Glossary
Notices

Codec type indication for Dolby Atmos content

For HTTP Live Streaming streams containing Dolby Digital Plus tracks with Dolby Atmos content, the CODEC attribute of the EXT-X-STREAM-INF parameter must include a value of ec-3 for indication of the audio codec. In addition, a CHANNELS attribute must be included in the #EXT-X-MEDIA parameter.

The value of the CHANNELS attribute is the number of decodable objects followed by a slash (/) and then JOC. JOC is the audio coding identifier for a Dolby Digital Plus bitstream with joint object coding data. The number of decodable objects is the decimal representation of the eight-bit bit field for complexity_index_type_a in the EC3SpecificBox of a Dolby Digital Plus audio track. The complexity_index_type_a parameter has a value range of 1 to 16.

For example, for a media presentation containing a Dolby Digital Plus bitstream with Dolby Atmos content, the CHANNELS attribute of the #EXT-X-MEDIA parameter must include the JOC identifier:

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="ATMOS",LANGUAGE="eng",
NAME="ATMOS Track",AUTOSELECT=YES,DEFAULT=YES,CHANNELS="16/JOC",
URI="../../DDP/ChID_voices_6ch_256kbps_ddp_sub.m3u8"

To ensure playback on systems that are not Dolby Atmos enabled, use one of the following options:

Include an equivalent 5.1 bitstream in your manifest with the CHANNELS attribute set to 6. The 5.1 bitstream must be added to the same #EXT-X-MEDIA group as the Dolby Atmos bitstream. We recommend adding a 5.1 bitstream since it provides lower bit rate options.
Reuse the Dolby Atmos bitstream and add an additional entry with the CHANNELS attribute set to 6 to the same #EXT-X-MEDIA group. In this way you only need to prepare one media asset.