Summary

This chapter began with an overview of the background audio player and showed how it is used to control the playback of local or remote audio files. You looked at how audio file information is represented by the AudioTrack class and examined the role of background audio agents, which are used to coordinate audio playback while your app is not running in the foreground. You saw that when used in the foreground, a BackgroundAudioPlayer forwards all calls to the registered AudioPlayerAgent. Conversely, when a BackgroundAudioPlayer is used in an AudioPlayerAgent, it directly affects playback on the device.

The chapter then demonstrated how to build a UI that leverages the background audio agent, for controlling playback while your app is in the foreground.

Finally, the chapter examined audio streaming agents, and you saw how they are used to provide custom streaming and decoding of audio files. You also saw how a custom audio streaming agent can be employed to play audio directly from an assembly resource, something not possible using the built-in streaming and decoding system of the phone.