About this plug-in

This plug-in allows sound designers to use audio from an external source, for example a network stream, or a microphone connected to the PC or console.

Integrating the plug-in

Aside from regular plug-in initialization (see Integration Details - Plug-Ins), integrating the Audio Input plugin requires the game to provide input audio data used by the various instances of the plug-in in the Wwise project. This is done through a callback mechanism, as exposed in AkAudioInputSourceFactory.h:

• At first, the game calls SetAudioInputCallbacks() to set the mandatory AkAudioInputPluginExecuteCallbackFunc which will be called whenever an instance of audio input requires more audio data.

  • If the audio data is not a mono stream of 32-bit floating point values, the AkAudioInputPluginGetFormatCallbackFunc must be set. This callback only accepts audio data in the following formats, where the left and right channels are stored as shown for a 16-frame buffer:

    • interleaved 16-bit integer (also known as planar)
      
    • non-interleaved 32-bit floating point
      

    AkAudioInputPluginGetFormatCallbackFunc uses AkAudioFormat which can be populated as shown in the example below: AkAudioFormat consists of audio data format specifications and channel configuration AkChannelConfig.

    AkChannelConfig can be set with the help of one of the calls mentioned below: AkChannelConfig.SetAnonymous(...), AkChannelConfig.SetStandard(...) or AkChannelConfig.SetAmbisonic(...)

    ChannelMask: There are no restrictions on channelmask. Standard and custom channelmasks are supported.

• Next, the game calls PostEvent to start the audio input plug-in.
• The Sound Engine will call AkAudioInputPluginGetFormatCallbackFunc once at the beginning of playback and then AkAudioInputPluginExecuteCallbackFunc at each audio frame until the plug-in finishes execution (either through a stop action or the execute callback setting AK_NoMoreData on io_pBufferOut->eState).

A very simple integration is demonstrated in the Microphone/AudioInput demo, using a microphone as the input. In the Integration Demo Wwise Project, a Sound Voice named Microphone uses the Audio Input plug-in as a source.

Note: In Wwise, the audio input plugin is fed with audio from the microphone input of the PC. If no microphone is connected, it will be silent.