Audio Management

The QNX SDK for Apps and Media uses the audio manager to route audio streams to output devices and to manage the behavior of concurrent audio streams.

Overview:

The QNX SDK for Apps and Media 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:

the audio stream with the highest priority takes precedence and has access to the preferred output device(s)
other audio streams are attenuated or muted, as required by the system configuration
media playback is stopped or paused when an audio stream is "ducked" in favor of a higher priority audio stream, and restarted when appropriate

Applications implemented using QNX SDK for Apps and Media should use the audio manager to route audio streams to their preferred output devices, and based on the configuration, attenuate or mute audio streams when higher-priorty audio stream types open. The audio manager doesn't pause or stop audio playback. 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:

automatic routing, and manual routing of the PCM preferred path
audio stream type identification
audio concurrency policy (ducking) management
audio device monitoring and mounting (e.g., headset, A2DP, HDMI)

For more information about using the audio manager, see Audio Manager Library Reference.

PPS objects:

The audio manager uses the PPS objects listed below. For information about these objects, see the relevant pages in the PPS Objects Reference.