Starting with Android 14, the Audio HAL interface is defined using Stable AIDL. Partners and SoC vendors are encouraged to reimplement their Audio HAL to provide an AIDL interface.

Extending the libaudiohal library adds framework support for AIDL HAL. With the AIDL implementation, the audio policy configuration specification is moved to AIDL HAL. With this change, the Audio Policy Manager (APM) gets the configuration from the HAL instead of consuming it from the vendor-provided XML file.

Audio AIDL HAL API

This section describes the Core, Effects, and Common HAL APIs for AIDL.

Use default implementation of the AIDL API at /hardware/interfaces/audio/aidl/default/ as a reference when implementing new versions of Audio HALs that interact with kernel drivers.

See the Audio HAL README file for the Audio HAL directory structure for AIDL.

Core HAL

Some of the key interfaces of Core HAL, using AIDL, are as follows:

• IModule.aidl is the entry point into the API.
• Streams are unidirectional and are used by AudioFlinger to send or receive audio to and from the HAL through IStreamOut.aidl and IStreamIn.aidl.
• ITelephony.aidl provides controls specific to telephony functions.
• IBluetooth.aidl provides BT SCO and HFP controls that were on IPrimaryModule in the HIDL API.
• IConfig.aidl provides system-wide configuration parameters.
• ISoundDose.aidl provides sound dose support. See Sound dose for more information.
• The latest version of the Core HAL API in development is in /hardware/interfaces/audio/aidl/android/hardware/audio/core/.
• The latest released version of the Core HAL API is in /hardware/interfaces/audio/aidl/aidl_api/android.hardware.audio.core/.

Effects HAL

Some of the key interfaces of Effects HAL, using AIDL, are as follows:

• IFactory.aidl is the entry point into the API.
• Descriptor.aidl contains all information such as capabilities and attributes for an effect implementation.
• Capability.aidl defines effect capabilities that don't change at runtime.
• Parameter.aidl defines all parameters supported by the effect instance.
• IEffect.aidl is used to configure and control particular effect instances.

• Effect-specific parcelables named after the effect.

• The latest version of the Effects HAL API in development is in /hardware/interfaces/audio/aidl/android/hardware/audio/effect/.

• The latest released version of the Effects HAL API is in /hardware/interfaces/audio/aidl/aidl_api/android.hardware.audio.effect.

See the Audio Effects for more information.

Common HAL

Data structures and interfaces shared between various HALs such as BT HAL, core and effects Audio HALs are in the Common HAL.

• The latest version of the Common AIDL HAL in development is in /hardware/interfaces/audio/aidl/android/hardware/audio/common/.

• The latest released version of the Common HAL API is in /hardware/interfaces/audio/aidl/aidl_api/android.hardware.audio.common/current/android/hardware/audio/common/.

Common stable data types

Stable data structure definitions are used both by HALs and the framework.

• The latest version of the stable data types in development is in /system/hardware/interfaces/media/aidl/android/media/audio/common/.

• The latest released version of the stable data types is in /system/hardware/interfaces/media/aidl_api/android.media.audio.common.types/.

Testing the Audio AIDL HAL API

New VTS tests are provided for the AIDL interface.

There are no changes in the new HAL version that can affect security.