@@ -1,91 +1,108 @@
//
// ToneOutputUnit .swift
// RecordAudio .swift
//
// This is a Swift 2.x class (which should be instantiated as a singleton object)
// that can record samples of audio input on iOS devices
// This is a Swift 3.0 class
// that uses the iOS Audio Unit v3 API and RemoteIO Audio Unit
// to record audio input samples,
// (should be instantiated as a singleton object.)
//
// Created by Ronald Nicholson rhn@nicholson.com on 5/01/2016.
// http://www.nicholson.com/rhn/
// Copyright © 2016 Ronald H Nicholson, Jr. All rights reserved.
// Created by Ronald Nicholson on 10/21/16.
// Copyright © 2016 HotPaw Productions. All rights reserved.
// BSD 2-clause license
//
import Foundation
import AVFoundation
import AudioUnit
// call setupAudioSessionForRecording() during controlling view load
// call startRecording() to start recording in a later UI call
final class RecordAudio : NSObject {
var auAudioUnit : AUAudioUnit ! = nil
var enableRecord = true
var sessionActive = false
var audioSetupDone = false
var running = false
var sampleRate : Double = 44100.0 // desired audio sample rate
var enableRecording = true
var audioSessionActive = false
var audioSetupComplete = false
var isRecording = false
var f0 = 880.0 // default frequency of tone
var v0 = 16383.0 // default volume of tone
var sampleRate : Double = 48000.0 // desired audio sample rate
let mBufferSize = 8192 // for Audio Unit AudioBufferList mData buffer
let cirBuffSize = 32768 // lock-free circular fifo/buffer size
var circBuffer = [ Int16] ( count: 32768 , repeatedValue: 0 )
let circBuffSize = 32768 // lock-free circular fifo/buffer size
var circBuffer = [ Float] ( repeating: 0 , count: 32768 )
var circInIdx : Int = 0 // sample input index
var circOutIdx : Int = 0 // sample output index
private var micPermission = false
private var micPermissionDispatchToken : dispatch_once_t = 0
private var interrupted = false // for restart from audio interruption notification
var audioLevel : Float = 0.0
private var micPermissionRequested = false
private var micPermissionGranted = false
// for restart from audio interruption notification
private var audioInterrupted = false
private var renderBlock : AURenderBlock ? = nil
func startRecording( ) {
if running { return }
self . enableRecord = true
if isRecording { return }
if ( sessionActive == false ) {
if audioSessionActive == false {
// configure and activate Audio Session, this might change the sampleRate
setupAudioSession ( )
setupAudioSessionForRecording ( )
}
guard micPermissionGranted && audioSessionActive else { return }
let audioFormat = AVAudioFormat (
commonFormat: AVAudioCommonFormat . PCMFormatInt16 , // short int samples
sampleRate: Double ( sampleRate) ,
channels: AVAudioChannelCount ( 2 ) ,
interleaved: true ) // interleaved stereo
commonFormat: AVAudioCommonFormat . pcmFormatInt16 , // pcmFormatInt16, pcmFormatFloat32,
sampleRate: Double ( sampleRate) , // 44100.0 48000.0
channels: AVAudioChannelCount ( 2 ) , // 1 or 2
interleaved: true ) // true for interleaved stereo
if ( auAudioUnit == nil ) {
setupRemoteIOAudioUnit ( audioFormat)
setupRemoteIOAudioUnitForRecord ( audioFormat : audioFormat)
}
// not running, so start hardware
let renderBlock = auAudioUnit. renderBlock
renderBlock = auAudioUnit. renderBlock // returns AURenderBlock()
if ( enableRecord && micPermission && audioSetupDone && sessionActive) {
let pcmBufferSize : UInt32 = UInt32 ( mBufferSize)
let inputBuffer = AVAudioPCMBuffer (
PCMFormat: audioFormat, frameCapacity: pcmBufferSize)
if ( enableRecording
&& micPermissionGranted
&& audioSetupComplete
&& audioSessionActive
&& isRecording == false ) {
auAudioUnit. isInputEnabled = true
auAudioUnit. inputEnabled = true
auAudioUnit. inputHandler = { // AUInputHandler?
( actionFlags, timestamp, frameCount, inputBusNumber) -> Void in
auAudioUnit. outputProvider = { // AURenderPullInputBlock()
let err : OSStatus =
renderBlock ( actionFlags, timestamp,
AUAudioFrameCount ( frameCount) , Int ( inputBusNumber) ,
inputBuffer. mutableAudioBufferList, nil )
( actionFlags, timestamp, frameCount, inputBusNumber, inputData) -> AUAudioUnitStatus in
if err == noErr {
// save samples from current input buffer to circular buffer
self . copyMicrophoneInputSamples ( inputBuffer. mutableAudioBufferList,
frameCount: UInt32 ( frameCount) )
if let block = self . renderBlock { // AURenderBlock?
let err : OSStatus = block ( actionFlags,
timestamp,
frameCount,
1 ,
inputData,
. none)
if err == noErr {
// save samples from current input buffer to circular buffer
self . recordMicrophoneInputSamples (
inputDataList: inputData,
frameCount: UInt32 ( frameCount) )
}
}
let err2 : AUAudioUnitStatus = noErr
return err2
}
do {
circInIdx = 0 // initialize circular buffer pointers
circOutIdx = 0
try . allocateRenderResources ( )
try . startHardware ( ) // equivalent to AudioOutputUnitStart ???
running = true
isRecording = true
} catch {
// placeholder for error handling
@@ -95,116 +112,99 @@ final class RecordAudio: NSObject {
func stopRecording( ) {
if ( running ) {
if ( isRecording ) {
auAudioUnit. stopHardware ( )
running = false
isRecording = false
}
if ( sessionActive ) {
if ( audioSessionActive ) {
let audioSession = AVAudioSession . sharedInstance ( )
do {
try . setActive ( false )
} catch /* let error as NSError */ {
}
sessionActive = false
audioSessionActive = false
}
}
private func copyMicrophoneInputSamples ( // process RemoteIO Buffer from mic input
private func recordMicrophoneInputSamples ( // process RemoteIO Buffer from mic input
inputDataList : UnsafeMutablePointer < AudioBufferList > ,
frameCount : UInt32 )
{
let inputDataPtr = UnsafeMutableAudioBufferListPointer ( inputDataList)
let mBuffers : AudioBuffer = inputDataPtr [ 0 ]
let count = Int ( frameCount)
// Microphone Input Analysis
let data = UnsafePointer < Int16 > ( mBuffers. mData)
let dataArray = UnsafeBufferPointer < Int16 > (
start: data,
count: Int ( mBuffers. mDataByteSize) / sizeof( Int16) ) // words
let bufferPointer = UnsafeMutableRawPointer ( mBuffers. mData)
var j = self . circInIdx // current circular array input index
let n = self . cirBuffSize
for i in 0 ..< ( count/ 2 ) {
self . circBuffer [ j ] = dataArray [ i+ i ] // copy left channel sample
self . circBuffer [ j + 1 ] = dataArray [ i+ i+ 1 ] // copy right channel sample
j += 2 ; if j >= n { j = 0 } // into circular buffer
}
OSMemoryBarrier ( ) ; // C11 call from libkern/OSAtomic.h
self . circInIdx = j // circular index will always be less than size
}
var measuredMicVol : Float = 0.0
let n = self . circBuffSize
var audioLevelSum : Float = 0.0
if let bptr = bufferPointer? . assumingMemoryBound ( to: Int16 . self) {
for i in 0 ..< ( count/ 2 ) {
// Save samples in circular buffer for latter processing
self . circBuffer [ j ] = Float ( bptr [ i+ i ] ) // Stereo Left
self . circBuffer [ j + 1 ] = Float ( bptr [ i+ i+ 1 ] ) // Stereo Right
j += 2 ; if j >= n { j = 0 } // Circular buffer looping
// Microphone Input Analysis
let x = Float ( bptr [ i+ i ] )
let y = Float ( bptr [ i+ i+ 1 ] )
audioLevelSum += x * x + y * y
func dataAvailable( enough : Int ) -> Bool {
let buff = self . circBuffer
var idx = self . circOutIdx
var d = self . circInIdx - idx
// set ttd to always try to consume more data
// than can be produced during about 1 measurement timer interval
if d < 0 { d = d + self . cirBuffSize }
if d >= enough { // enough data in fifo
var sum = 0.0
for _ in 0 ..< enough {
// read circular buffer and increment circular index
let x = Double ( buff [ idx] )
idx = idx + 1 ; if idx >= 32768 { idx = 0 }
// calculate total energy in buffer
sum = sum + ( x * x)
}
self . circOutIdx = idx
measuredMicVol = sqrt ( Float ( sum) / Float( enough) ) // scaled volume
return ( true )
}
return ( false )
OSMemoryBarrier ( ) ; // from libkern/OSAtomic.h
self . circInIdx = j // circular index will always be less than size
if audioLevelSum > 0.0 && count > 0 {
audioLevel = logf ( audioLevelSum / Float( count) )
}
}
// set up and activate Audio Session
private func setupAudioSession ( ) {
func setupAudioSessionForRecording ( ) {
do {
let audioSession = AVAudioSession . sharedInstance ( )
if ( enableRecord && micPermission == false ) {
dispatch_once ( & micPermissionDispatchToken) {
if ( micPermissionGranted == false ) {
if ( micPermissionRequested == false ) {
micPermissionRequested = true
audioSession. requestRecordPermission ( { ( granted: Bool ) -> Void in
if granted {
self . micPermission = true
self . micPermissionGranted = true
self . startRecording ( )
return
} else {
self . enableRecord = false
self . enableRecording = false
// dispatch in main/UI thread an alert
// informing that mic permission is not switched on
}
} )
}
return
}
if enableRecord {
if enableRecording {
try . setCategory ( AVAudioSessionCategoryRecord)
}
var preferredIOBufferDuration = 0.0058 // 5.8 milliseconds = 256 samples
let hwSRate = audioSession. sampleRate // get native hardware rate
if hwSRate == 48000.0 { sampleRate = 48000.0 } // fix for iPhone 6s
if hwSRate == 48000.0 { preferredIOBufferDuration = 0.0053 }
try . setPreferredSampleRate ( sampleRate)
let preferredIOBufferDuration = 0.0053 // 5.3 milliseconds = 256 samples
try . setPreferredSampleRate ( sampleRate) // at 48000.0
try . setPreferredIOBufferDuration ( preferredIOBufferDuration)
NSNotificationCenter . defaultCenter ( ) . addObserverForName (
AVAudioSessionInterruptionNotification,
object: nil , queue: nil ,
usingBlock: myAudioSessionInterruptionHandler)
NotificationCenter . default. addObserver (
forName: NSNotification . Name. AVAudioSessionInterruption,
object: nil ,
queue: nil ,
using: myAudioSessionInterruptionHandler )
try . setActive ( true )
sessionActive = true
audioSessionActive = true
} catch /* let error as NSError */ {
// placeholder for error handling
}
}
// find and set up the sample format for the RemoteIO Audio Unit
private func setupRemoteIOAudioUnit ( audioFormat : AVAudioFormat ) {
private func setupRemoteIOAudioUnitForRecord ( audioFormat : AVAudioFormat ) {
do {
let audioComponentDescription = AudioComponentDescription (
@@ -221,48 +221,50 @@ final class RecordAudio: NSObject {
let bus1 = auAudioUnit. outputBusses [ 1 ]
try . setFormat ( audioFormat) // for microphone bus
audioSetupDone = true
audioSetupComplete = true
} catch /* let error as NSError */ {
// placeholder for error handling
}
}
private func myAudioSessionInterruptionHandler( notification: NSNotification ) {
private func myAudioSessionInterruptionHandler( notification: Notification ) -> Void {
let interuptionDict = notification. userInfo
if let interuptionType = interuptionDict ? [ AVAudioSessionInterruptionTypeKey] {
let interuptionVal = AVAudioSessionInterruptionType (
rawValue: interuptionType. unsignedIntegerValue )
if ( interuptionVal == AVAudioSessionInterruptionType . Began ) {
rawValue: ( interuptionType as AnyObject ) . uintValue )
if ( interuptionVal == AVAudioSessionInterruptionType . began ) {
// [self beginInterruption];
if ( running ) {
if ( isRecording ) {
auAudioUnit. stopHardware ( )
running = false
isRecording = false
let audioSession = AVAudioSession . sharedInstance ( )
do {
try . setActive ( false )
sessionActive = false
audioSessionActive = false
} catch {
// placeholder for error handling
}
interrupted = true
audioInterrupted = true
}
} else if ( interuptionVal == AVAudioSessionInterruptionType . Ended ) {
} else if ( interuptionVal == AVAudioSessionInterruptionType . ended ) {
// [self endInterruption];
if ( interrupted ) {
if ( audioInterrupted ) {
let audioSession = AVAudioSession . sharedInstance ( )
do {
try . setActive ( true )
sessionActive = true
audioSessionActive = true
if ( auAudioUnit. renderResourcesAllocated == false ) {
try . allocateRenderResources ( )
}
try . startHardware ( )
running = true
isRecording = true
} catch {
// placeholder for error handling
}
}
}
}
}
}
} // end of RecordAudio class
// eof
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