Dolby Atmos changes the way sound works on Android by adding 3D spatial sound based on objects. This article will show you how to successfully add Dolby Atmos and Dolby MS12 to your AOSP-based Android platform. We’ll cover everything from libraries and HAL changes to efuse provisioning and certification- — all part of the AOSP engineering services we deliver to help OEMs and developers build high-performance Android devices.
What sets Dolby Atmos apart from other sound systems?
1. Object-Based Audio:
- Dolby Atmos considers each sound as an object, while traditional audio uses channels (like 5.1 or 7.1 setups).
- These sound objects are placed and moved around in a 3D space, which makes the experience more immersive than ever.
2. Object-Based Audio:
- Dolby Atmos incorporates height channels to sound, which gives it an overhead dimension.
- This makes it possible for things like rain falling from above or a helicopter flying by.
3. Scalability:
- Dolby Atmos is very flexible and works perfectly on everything from complex movie theatre setups to soundbars, headphones, and mobile devices.
4. Enhanced Clarity:
- Dolby Atmos makes sound clearer and separates audio elements better by placing sound exactly where it should be. This improves both dialogue and sound effects.
Applications of Dolby Atmos
- Cinemas: Initially, Dolby Atmos was designed for theatres, where it gives you an immersive movie experience.
- Home Entertainment: Soundbars that work with Dolby and streaming services like Netflix and Prime Video that work with Atmos.
- Music: Apple Music and Tidal are two music streaming services that now have Dolby Atmos-powered spatial audio tracks.
- Gaming: Xbox and PC games that support Dolby Atmos give players realistic, 360-degree sound.
- Mobile Devices: Dolby Atmos works on a lot of smartphones, which lets you hear movies, music, and games in 3D sound.
What is Dolby MS12?
Dolby Multistream Decoder, or Dolby MS12, is a complete audio solution for a wide range of consumer electronics, such as TVs, set-top boxes, and streaming devices. It supports a wide range of audio formats and advanced audio processing features, which makes sure that it works with a wide range of devices and platforms and has better sound quality — something our AOSP engineering services handle from integration to optimization.
Key Features of Dolby MS12
1. Multi-Format Decoding:
- Supports Dolby Digital (AC-3), Dolby Digital Plus (E-AC-3), Dolby TrueHD, Dolby Atmos, AAC, HE-AAC, and Dolby AC-4.
2. Audio Processing Pipeline:
- Input Processing:
- Format Detection: Identifies the incoming audio format.
- Bitstream Parsing: Extracts audio data and metadata from the bitstream.
- Decoding:
- Core Decoding: Converts compressed audio formats into PCM (Pulse Code Modulation) format.
- Object-Based Decoding: Decodes audio objects and metadata for Dolby Atmos.
- Post-Processing:
- Loudness Management: Maintains consistent audio levels across different content.
- Dynamic Range Control: Adjusts dynamic range to suit various listening environments.
- Dialogue Enhancement: Enhances speech clarity, especially in noisy environments.
- Bass Management: Optimizes low-frequency sounds for diverse speaker setups.
- Output Processing:
- Downmixing: Converts multi-channel audio to fewer channels (e.g., 7.1 to 2.0).
- Upmixing: Enhances stereo content to multi-channel output.
- Metadata Embedding: Adds metadata for playback devices
3. Advanced Features:
- Intelligent Loudness for following ITU-R rules.
- Dolby Atmos extensions let Dolby Digital Plus signals pass through automatically.
- Support for the Netflix Ready Device Platform SDK built in, which makes it easier to use with streaming services.
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Technical Benefits of Dolby MS12
1. Efficiency:
- Combines different audio technologies, so you don’t need as many separate decoders.
2. Flexibility:
- Works with a lot of different audio formats and settings.
3. Scalability:
- Can be used on a range of DSP platforms, so it works with a wide range of devices.
Use Cases
- Smart TVs: Improves audio quality for broadcast and streaming content.
- Set-Top Boxes: Ensures high-quality audio for cable and satellite TV.
- Streaming Devices: Decodes and improves audio from streaming services.
DSP Implementation of Dolby MS12
Dolby MS12 uses Digital Signal Processing (DSP) platforms like CEVA-BX2 to get its advanced audio features. The DSP structure has:
1. Input Stage:
- Format Detection
- Bitstream Parsing
2. Decoding Stage:
- Core Decoding
- Object-Based Decoding
3. Post-Processing:
- Loudness Management
- Dynamic Range Control
- Dialogue Enhancement
4. Output Stage:
- Downmixing
- Upmixing
1. Understanding Dolby Atmos Integration
For Dolby Atmos to work, both hardware and software are needed.
Our AOSP engineering services cover the entire workflow — from adding Dolby libraries:
- Adding libraries from Dolby, such as libdolbyms12.so and libHwAudio_dcvdec.so.
- Efuse provisioning to turn on Dolby audio on the target SoC.
- Changing the AOSP source code to add Dolby Atmos effects to the audio pipeline.
2. Prerequisites
Before starting the integration, ensure you have:
Files and Libraries
- Dolby MS12 Library: libdolbyms12.so (encrypted version).
- Dolby License Library: libHwAudio_dcvdec.so for AC3/EAC3 decoding
- Efuse Pattern Generator: Script for generating efuse patterns based on a unique Dolby-provided customer ID.
Hardware Support
- Ensure your SoC (e.g., Amlogic T5, S5) supports Dolby Atmos and efuse burning.
- A Dolby-certified audio processor or DSP.
Licensing
- A valid Dolby licensing agreement.
3. Step-by-Step Integration Process
Step 1: Adding Dolby Libraries
1. Replace Existing Libraries: Replace the outdated
libHwAudio_dcvdec.so in the AOSP workspace with the latest Dolby license version
Path: /vendor/<manufacturer>/prebuilt/libstagefrighthw/lib/
2. Add Encrypted Dolby MS12 Library: Place libdolbyms12.so in the following directory:
Path: device/<manufacturer>/common/dolby_ms12/install/
encrypted_lib/libdolbyms12.so
Step 2: Efuse Provisioning
1. Generate Efuse Pattern: Use the provided script to generate an efuse pattern with the Dolby Customer ID:
cd bootloader/uboot-repo/
./fip/audio_id_gen.sh --audio-id 0x9AB1ZC24 --soc t5 -o audio_id.efuse
Replace 0x9AB1ZC24 with your unique Dolby Customer ID. That is provided by vendor.
2. Burn Efuse Pattern:
Copy the audio_id.efuse file to a USB drive and burn it using U-Boot:
usb start
fatload usb 0 12000000 audio_id.efuse
efuse <manufacturer>_set 12000000
Verify success with the message: <Manufacturer_name> EFUSE pattern programming success!
Step 3: Library Decryption
After booting the device, the encrypted libdolbyms12.so is decrypted automatically. Ensure the following components are in place:
- Decryption Tool: /vendor/bin/dolby_fw_dolbyms12
- Decryption Script: /vendor/etc/init/dolby_fw_dolbyms12.rc
- The decrypted library is saved as: Out/target/product/
product_name/odm/lib/ms12/libdolbyms12.so
Take your Android audio to the next level
Step 4: Modify Audio HAL
1. Update Audio Effects Configuration: Add Dolby Atmos to audio_effects.xml:
<effectProxy name="dolby_atmos" library="libdolbyms12" uuid="xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"/>
2. Integrate Dolby in Audio Policy: Modify AudioPolicyManager.cpp to route audio streams through the Dolby Atmos engine.
Step 5: Framework-Level Changes
1. Update AudioService: Modify AudioService.java to include methods for enabling/disabling Dolby Atmos effects.
2. Add UI Controls in Settings: Integrate toggles for Dolby Atmos in the Android Settings app under Sound settings.
Step 6: Testing and Validation
1. Play Dolby Atmos Content: Use apps like Netflix or Prime Video to play Dolby Atmos-enabled content.
2. Check Logs: Use adb logcat to verify Dolby library functionality:
adb logcat | grep libdolbyms12
Example logs: I libdolbyms12: Dolby MS12 SIDK version: Version:2.4.0.b419a3a8
I libdolbyms12: Dolby security recognize success!
3. Validate Efuse Status: Verify efuse burning status in U-Boot:
efuse_obj get_lock AUDIO_VENDOR_ID
A return value of 01 indicates success.
Our AOSP engineering services follow these exact steps, ensuring your integration meets Dolby’s certification requirements without compromising device stability.
4. Packaging and Deployment
1. Include Dolby Files in Build: Add proprietary Dolby files to Android.mk or Android.bp:
cc_library_shared {
name: "libdolbyms12",
srcs: ["libdolbyms12.so"],
proprietary: true,
vendor: true,
}
2. Certify the Build: Ensure the integration passes Dolby certification for proper functionality.
5. Best Practices and Notes
- Don’t overwrite efuses: Reburning different efuse patterns on the same board can permanently damage it.
- Licensing Compliance: Make sure you follow Dolby’s licensing rules before you give out the product.
- Testing: Try out the integration in different situations, like with headphones, speakers, and different audio tracks.
Conclusion
When you add Dolby Atmos to AOSP, your device delivers premium, spatial audio for movies, music, and games. With our AOSP engineering services, we handle everything from HAL modifications to certification, ensuring your Android product meets both technical and market expectations.