# echoTouch

echoTouch demonstrates using the Voice Processing I/O audio unit for handling audio input and output. The application tests local audio playback and simulated "far-talker" audio playback allowing you to record and listen back to the results. It also lets you to turn on/off the VPIO comparing the recorded results.

The Voice Processor I/O audio unit was discussed in the WWDC Session "Fundamentals of Digital Audio for Mac OS X and iPhone OS" which can be found here: < https://developer.apple.com/devcenter/download.action?path=/videos/wwdc_2010__sd/session_411__fundamentals_of_digital_audio_for_mac_os_x_and_iphone_os.mov >

## Main Files

ViewController.mm

- Source for the main sample implementation.

ViewController.h

- Header for main controller class.

echoTouchHelper.cpp

- Utility functions for setting up the I/O unit, AVAudioSession and loading data for the simulated input audio.

echoTouchHelper.h

- Headear for echoTouchHelper.cpp

echoTouchAppDelegate

- Standard App delegate files.

MeteringViews Folder

- Classes implementing the VU meters.

PublicUtility Folder

- AUOutputBuffer class

- CAStreamBasicDescription class

Audio Folder

- fx.caf : Sound Effects audio file.

- sampleVoiceXXXkHz.wav : Simulated far-talker audio files at various sample rates.

## Version History

Version 1.0 - Initial release.

## Requirements

### Build

Xcode 8.0, iOS 10 SDK

### Runtime

macOS 10.11.6 or greater

iOS 9.3 or greater

Copyright (C) 2016 Apple Inc. All rights reserved.