audiosystem-passthrough

For new adaptations audioflingerglue (and pulseaudio-modules-droid-glue) should not be used!

Features and command line arguments

Operation modes (types)

• af - AudioFlinger
  • Normal mode
  • Dummy mode - exposes the service but only replies OK to all method calls)
• qti - IQcRilAudio
  • Devices which use [email protected]::IQcRilAudioCallback or [email protected]::IQcRilAudioCallback hidl service for setting voice call related parameters.
• hw2_0 - [email protected]
  • Devices which use [email protected]::IDevicesFactory/default and [email protected]::IDevice services for setting voice call related parameters. Right now hw2_0 has only dummy implementation.

Command line arguments

-v --verbose   Verbose logging from audiosystem-passthrough
-a --address   D-Bus address for PulseAudio module interface
-i --idx       Starting index for binder calls, only applicable with operation type af
-t --type      Passthrough type. Can be af or qti
--module       Run as child process of PulseAudio module

Also passthrough type and idx arguments can be provided from environment variables
AUDIOSYSTEM_PASSTHROUGH_TYPE={qti,af,hw2_0}
AUDIOSYSTEM_PASSTHROUGH_IDX={17,18} # only applicable to af type

How to use audiosystem-passthrough

As helper for pulseaudio-modules-droid-hidl

When run from the droid-hidl module the module tries to autodetect correct configuration for the helper. If autodetection fails you can modify PulseAudio sysconfig file (/etc/sysconfig/pulseaudio) and add following environment variables:

AUDIOSYSTEM_PASSTHROUGH_TYPE={qti,af,hw2_0}
AUDIOSYSTEM_PASSTHROUGH_IDX={17,18} # only applicable to af type

Type qti is for devices which have qti HIDL interface IQcRilAudio.

In standalone dummy mode

Package audiosystem-passthrough-dummy-af contains a service file which starts audiosystem-passthrough in AudioFlinger dummy mode. This can be used on devices where AudioFlinger service needs to be present but isn't used for anything.

Package audiosystem-passthrough-dummy-hw2_0 contains a service file which starts audiosystem-passthrough in [email protected] dummy mode. This can be used on devices where [email protected] service needs to be present but isn't used for anything.

Configuration possibilites matrix

What is needed and when

Qualcomm chipsets

Android <= 8:

• for voice calls: AudioFlinger
• for media (camera etc): AudioFlinger (o)

Android >= 9:

• for voice calls: IQcRilAudio
• for media (camera etc): AudioFlinger (o)

Other chipsets

All? Android versions:

• for media (camera etc): AudioFlinger (o)

(o): Depends, that is, some devices might not need this but others do.

What can satisfy dependencies

AudioFlinger

For voice calls, one of

• pulseaudio-modules-droid-hidl and audiosystem-passthrough (with af type)
• pulseaudio-modules-droid-glue and audioflingerglue

For media, one of

• audiosystem-passthrough-dummy-af (from package audiosystem-passthrough)
• audioflingerglue

If device needs AudioFlinger for both voice calls and media and a combination of pa-modules-droid-hidl and audiosystem-passthrough is used a single instance of audiosystem-passthrough running under pulseaudio-modules-droid-hidl is enough.

IQcRilAudio

For voice calls,

• pulseaudio-modules-droid-hidl and audiosystem-passthrough (with qti type)