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HTTP Live Streaming playlist files with Dolby AC-4 Requirements and recommendations for a playlist that lists entries for a presentation that includes Dolby AC-4 content are described.
Codec type indication for Dolby AC-4 The codec type must be indicated in an HLS playlist.

Introduction to Dolby AC-4 and HTTP Live Streaming specificationThis information set specifies the required data formatting and signaling between the server (sender) and the clients (receivers) to enable Dolby AC-4 to be used as an audio format within HTTP Live Streaming A/V delivery applications in conjunction with packed audio or ISO base media file format.
Dolby AC-4 packetization into a fragmented MP4 file The process of analyzing and preparing a Dolby AC-4 bitstream for storage within a fragmented MP4 file is described. AC-4 sync frames must be converted to raw AC-4 frames before packetization.
Dolby AC-4 packetization into HTTP Live Streaming compliant audio-only elementary stream segmentsWhen multiplexing a Dolby AC-4 audio elementary stream into HTTP Live Streaming compliant audio-only elementary stream segments, the product must meet certain conditions.
HTTP Live Streaming playlist files with Dolby AC-4 Requirements and recommendations for a playlist that lists entries for a presentation that includes Dolby AC-4 content are described.
- CHANNELS attributeAll EXT-X-MEDIA parameters for audio components should have a CHANNELS attribute.
- Codec type indication for Dolby AC-4 The codec type must be indicated in an HLS playlist.
- Codec type indication for immersive stereo contentFor HTTP Live Streaming streams containing Dolby AC-4 tracks with immersive stereo content, the CODEC attribute of the EXT-X-STREAM-INF parameter follows the same requirements for regular Dolby AC-4 content. In addition, a CHANNELS attribute must be included in the #EXT-XMEDIA parameter.
- Examples of HTTP Live Streaming playlist files with Dolby AC-4 Examples of HTTP Live Streaming playlist files that contain Dolby AC-4 bitstreams are provided.
Demultiplexing Dolby AC-4 bitstreams from an ISO base media file segmentBuffering must be considered when product designers implement an ISO base media file format file demultiplexer that supports Dolby AC-4 bitstreams.
HTTP Live Streaming and Dolby AC-4 overviewIntroduction about HLS and Dolby AC-4
Glossary
Notices

Codec type indication for Dolby AC-4

The codec type must be indicated in an HLS playlist.

For media streams containing Dolby AC-4, we recommend using the CODEC attribute of the EXT-X-STREAM-INF parameter to indicate the codec type. The CODEC must include a dot-separated four-part value for media presentations using Dolby AC-4, as shown in this example:

#EXT-X-STREAM-INF:BANDWIDTH=3464568,CODECS="avc1.640028,ac-4.02.01.01"
example.m3u8

The FourCC ac-4 part indicates that the codec is Dolby AC-4. The latter three parts are represented by two-digital hexadecimal numbers and indicate these parameters sequentially:

The bistream_version as indicated in the ac4_toc(), which is defined in ETSI TS 103 190-2
The presentation_version as indicated for the presentation in the ac4_toc(), which is defined in ETSI TS 103 190-2
The mdcompat parameter as indicated for the presentation in the ac4_toc(), which is defined in ETSI TS 103 190-2

An object type indicator (OTI) value must not be appended to the ac-4 string.^[1]

[1] The object type indicator value is not defined for Dolby AC-4.