iPhoneMultichannelMixerTest

===========================================================================

DESCRIPTION:

iPhoneMultichannelMixerTest demonstrates how to build an Audio Unit Graph connecting a MultiChannel Mixer instance

to the RemoteIO unit.

Two input busses are created each with input volume controls. An overall mixer output volume control is also provided

and each bus may be enabled or disabled.

All the relevant code is in the file MultichannelMixerController.mm while the supporting UI code is in MyViewController.m

Touching the "Play Audio" button simply calls AUGraphStart while "Stop Audio" calls AUGraphStop. Changing AU volume is

performed via AudioUnitSetParameter.

Audio data is provided from two single channel audio files. Each single channel of data

(a guitar riff and drum groove respectively) is rendered to a single channel of each input bus resulting in the guitar

on the left channel and the drums on the right channel at the output. This serves no specific purpose other than making

for an obvious sample where you can turn off and change the volume of each input and be very aware of the results.

===========================================================================

RELATED INFORMATION:

Audio Session Programming Guide

Core Audio Overview

Audio Unit Processing Graph Services Reference

Output Audio Unit Services Reference

System Audio Unit Access Guide

Audio Component Services Reference

Audio File Services Reference

AudioToolbox/AUGraph.h

AudioToolbox/ExtendedAudioFile.h

===========================================================================

SPECIAL CONSIDERATIONS:

None

===========================================================================

BUILD REQUIREMENTS:

iOS 4.0 SDK

===========================================================================

RUNTIME REQUIREMENTS:

iPhone OS 3.2 or later

===========================================================================

PACKAGING LIST:

MultichannelMixerTestDelegate.h

MultichannelMixerTestDelegate.m

The MultichannelMixerTestDelegate class defines the application delegate object, responsible for adding the navigation

controllers view to the application window, setting up the Audio Session and so on.

MyViewController.h

MyViewController.m

The MyViewController class defines the controller object for the application. The object helps set up the user interface,

responds to and manages user interaction, and communicates with the MultichannelMixerController.

MultichannelMixerController.h

MultichannelMixerController.mm

This file implements setting up the AUGraph, loading up the audio data using ExtAudioFile, the input render procedure and so on.

All the code demonstrating interacting with Core Audio is in this one file, the rest of the sample can be thought of as a simple

framework for the demonstration code in this file.

===========================================================================

CHANGES FROM PREVIOUS VERSIONS:

Version 1.1, upgraded project to build with the iOS 4 SDK.

Version 1.0, tested with iPhone OS 3.0. First public release.

================================================================================

Copyright (C) 2009-2010 Apple Inc. All rights reserved.