Audio Management

The QNX CAR platform uses the audio manager to route audio streams to output devices, and the audio manager and the now playing service to manage the behavior of concurrent audio streams.


The QNX CAR platform supports diverse audio stream types (sound effects, ringtones, media from a media player, etc.). Each audio stream type must be routed to the most appropriate output device (speakers, headphones, etc.). When two or more audio streams request access to an output device, applications must know which audio stream takes priority, and what should be done with the other audio streams so that:

Applications implemented on the QNX CAR platform should use the audio manager to route audio streams to their preferred output devices, and to attenuate or mute audio streams when higher-priorty audio stream types open, based on the configuration. The audio manager doesn't pause or stop audio playback, however. For example, the audio manager may mute media playback when the telephone rings, but the media will continue playing. Applications should use the now playing service to manage pausing and stopping playback.

Audio manager

The audio manager and its library of functions and data structures provide:

For more detailed information about using the audio manager, see Audio Manager Library Reference. For information about the PPS objects used by the audio manager in QNX CAR, see "Audio manager PPS objects".

Now playing service

The now playing service (nowplaying) can be used along with the audio manager to manage audio stream concurrency. It supports two distinct PPS interfaces, one for media players (including phones), and one for media controllers.

All media players and media controllers on a system should register with the now playing service and subscribe and publish to the relevant PPS objects in order to know what other media players and controllers are doing, and to let other players and controllers know what they are doing.

For more detailed information about using the now playing service, see "Now Playing Service".