Audio Session Categories
Category identifiers for audio sessions, used as values for the Kaudiosessionproperty_audiocategory property.
Overview
Each app running in iOS has a single audio session, which in turn has a single category. You can change your audio session’s category while your app is running.
You can refine the configuration provided by the kAudioSessionCategory_RecordAudio and kAudioSessionCategory_PlayAndRecord categories by using an audio session mode, as described in Audio Session Modes.
Use the kAudioSessionCategory_AmbientSound category when you want your sounds to mix with other audio (such as from the iPod app). Use one of the other playback categories when you want audio from other apps to be silenced when your session is active. However, you can enable mixing for the kAudioSessionCategory_MediaPlayback and kAudioSessionCategory_PlayAndRecord categories by using the kAudioSessionProperty_OverrideCategoryMixWithOthers property. For more information on audio session categories, see Audio Session Programming Guide.