Audio Concurrency Management

You can manage multiple audio streams using various audio policies.

The policies control the following audio concurrency management features:

• Audio ducking (referred to as simply ducking) manages concurrent audio playback where playing one audio stream lowers the volume of another stream. Whether one audio stream causes another stream to duck (lower in volume) is determined by priorities that you configure.
• Audio ramping (referred to as simply ramping) gradually increases or decreases the volume of an audio stream so that it fades in or fades out. This effect makes ducking less abrupt.
• When audio preemption (or preemption) is configured and the system ducks an audio stream, it also temporarily suspends the playing of that stream. You specify preemption options by audio type.
• Audio type volume controls allow you to apply volume settings to all audio streams of a particular audio type.

You configure audio policies in the audio policy configuration file, which you specify using policy_conf in the [AUDIOMGMT] section of the audio configuration file. Each audio concurrency management context has its own audio policy configuration file and associated mixer device.

If your application needs to monitor the system's audio concurrency management changes, you can use control events. For more information, see “Control events” in the “Audio Architecture” chapter of this guide.