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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.
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.
Segmenting MPEG-2 transport streams

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.
  - Segmenting MPEG-2 transport streams
  - Video and audio data offset
- 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.
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

Segmenting MPEG-2 transport streams

Perform transport stream segmentation based on the presentation time stamps (PTSs) in the transport stream. Ensure that the difference between the first (earliest) PTS in segment n and segment n + 1 is less than or equal to the segment duration indicated by the #EXT-X-TARGETDURATION attribute.

Do not split PES packet data between segments. Because A/V streams consist of interleaved PES packet data in most cases, reorganizing transport stream packet data may be required.^[1]

Because random access is limited in HTTP Live Streaming to segment boundaries, a single Program Association Table (PAT) and Program Map Table (PMT) table is sufficient in the beginning of each segment. A PAT followed by a PMT is required for media decoding. Table repetition inside the segment is not required and may be omitted to save bandwidth.

For optimal bandwidth efficiency, we recommend the use of variable bit-rate transport stream segments over a constant bit rate. Convert constant bit-rate transport stream segments to variable bit rate by removing any null packets present in the transport stream segment.

[1] In a variable bit-rate transport stream, this can be achieved relatively easily by moving the transport stream packets of the corresponding PES packet from segment n + 1 to the end of the segment n.