ExoPlayer example code for Dolby Atmos support

  • Aug 3, 2023
  • Knowledge

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ExoPlayer example code for Dolby Atmos support
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ExoPlayer, Dolby Atmos, Android,
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ExoPlayer-example-code-for-Dolby-Atmos-support
Created By
MCW, 8/3/2023 12:28 AM
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Last Modified By
DFrehner, 8/3/2023 4:11 PM
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Article Content

Introduction

For app developers who prefer to customize an existing or alternative media framework to enable support for Dolby Atmos in their Android mobile app, modifications made to the ExoPlayer library for enabling Dolby Atmos playback can be used as a reference. 

ExoPlayer library support for Dolby Atmos

The ExoPlayer library consists of the following individual libraries; you can add the full library to your application, or add an individual library to your application as needed:

  • The ExoPlayer core library is a required library that provides core functionalities.
  • The ExoPlayer DASH library provides support for DASH content.
  • The ExoPlayer HLS library provides support for HLS content.
  • The ExoPlayer user interface (UI) library provides UI components and resources for use with ExoPlayer.

For Dolby Digital Plus and Dolby Digital Plus with JOC content playback support, we made code changes in the ExoPlayer core, DASH, HLS, and Smooth Streaming libraries. For Dolby AC-4 playback support, we made code changes in the ExoPlayer core and HTTP Live Streaming (HLS) libraries.

Example code for Dolby Digital Plus and Dolby Digital Plus with JOC content support

ExoPlayer includes codes to recognize Dolby Digital Plus and Dolby Digital Plus with JOC content audio format, to recognize and extract the audio stream from the container format. The example code describes all available code changes for Dolby content support in ExoPlayer.

Audio format

Refer to the following files for codes that enable ExoPlayer to recognize Dolby Digital Plus and Dolby Digital Plus with JOC content as an audio stream.

Example code description

File path

Defines ENCODING_E_AC3 audio format

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/C.java

Defines MimeTypes as eac3 and eac3‑joc and enables get function to the MimeTypes

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java

Enables get function to Dolby Atmos frame for each audio sample

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java

Enables function to add MediaCodecInfo for Dolby Digital Plus and Dolby Digital Plus with JOC content stream

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecInfo.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecUtil.java

Defines Dolby Digital Plus and Dolby Digital Plus with JOC content frame parser

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/audio/Ac3Util.java

Container format

Refer to the following files for codes that enable ExoPlayer to extract Dolby Digital Plus and Dolby Digital Plus with JOC content audio stream from the container format. 

Example code descritpion

File path

Enables demultiplexing Dolby Digital Plus and Dolby Digital Plus with JOC content from MP4 container

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/Atom.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/ AtomParsers.java

Streaming format

Refer to the following files for enabling ExoPlayer to recognize Dolby Digital Plus and Dolby Digital Plus with JOC content audio format from streaming.

Example code description

File path

Enables parsing of an HLS playlist file to identify Dolby Digital Plus and Dolby Digital Plus with JOC content

<ExoPlayer-Root>/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/DefaultHlsExtractorFactory.java

Enables parsing of a DASH manifest file to identify Dolby Digital Plus and Dolby Digital Plus with JOC content

<ExoPlayer-Root>/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DefaultManifestParser.java

Example code for Dolby AC‑4 support

ExoPlayer includes codes to recognize Dolby AC‑4 audio format, and to recognize and extract Dolby AC‑4 audio formatcontent audio stream from the container format.

Audio format

Refer to the files listed in the following table for codes that enable ExoPlayer to recognize Dolby AC‑4 as an audio stream.

Example code description

File path

Defines ac4 audio format

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/C.java

Defines MimeTypes as ac4 and enables get function to the MimeTypes

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/util/MimeTypes.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java

Enables get function to AC‑4 frame for each audio sample

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/audio/DefaultAudioSink.java

Defines AC‑4 frame parser

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/audio/Ac4Util.java

Container format

Refer to the files listed in the following table for codes that enable ExoPlayer to extract an Dolby AC‑4 audio stream from the container format.

Definitions in ETSI TS 103 190-2 v1.2.1, Digital Audio Compression (AC-4) Standard, Part 2; Immersive and Personalized Audio, are referenced by the following example codes:

  • Example code of AC-4 demultiplexer for MP4 container refers to Annex E (normative).
  • Example code of AC-4 synchronization frame refers to Annex C (normative). 

Example code description

File path

Enables demultiplexing AC-4 content from MP4 container

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/Atom.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/AtomParsers.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/FragmentedMp4Extractor.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/mp4/Mp4Extractor.java

Enables parsing AC-4 synchronization frame

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/Ac4Extractor.java

<ExoPlayer-Root>/library/core/src/main/java/com/google/android/exoplayer2/extractor/ts/Ac4Reader.java

Streaming format

Refer to the files listed in the following table for enabling ExoPlayer to recongize and extract Dolby AC‑4 audio format from streaming.

Example code description

File path

Enables parsing of an HLS playlist file to identify AC-4 content

<ExoPlayer-Root>/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/DefaultHlsExtractorFactory.java

Application Development - Android




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