Audio Player in swift is not getting value of volume and pitch - ios

Question

I am trying to make an audio player in SwiftUI, Audio player should have these functionality.
Play/Stop Audio
Play in loop
Change volume through slider
Change audio pitch through slider.
There are two problem currently I am facing
audio player is not using volume and pitch slider value
While I stop and play and change volume/pitch slider app crashes with following message.
2020-10-14 17:34:08.957709+0530 SwiftUIAudioPlayer[1369:24886] [avae]
AVAEInternal.h:109 [AVAudioFile.mm:484:-[AVAudioFile
readIntoBuffer:frameCount:error:]:
(ExtAudioFileRead(_imp->_extAudioFile, &ioFrames,
buffer.mutableAudioBufferList)): error -50
Here is the link to project. https://github.com/varun-naharia/SwiftUIAudioPlayer
ContentView.swift
import Foundation
import SwiftUI
struct ContentView: View {
#State var volume:Double = 0.00
#State var pitch:Double = 0.0
#State var musicFiles:[SoundModel] = [SoundModel(file: "metro35", name: "Metronome", fileExtension: "wav"), SoundModel(file: "johnson_tone_down_5min", name: "Johnson", fileExtension: "wav"), SoundModel(file: "sine_140_6s_fade_ogg", name: "Sine wave", fileExtension: "wav")]
#State var selectedMusicFile:SoundModel = SoundModel(file: "sine_140_6s_fade_ogg", name: "Sine wave", fileExtension: "wav")
#State var showSoundPicker = false
#State var selectedGraph = "skin_conductance"
#State var iconSize:CGFloat = 0.124
#State var iconSpace:CGFloat = 0.015
#State var heart = false
init() {
Player.setPitch(pitch: Float(self.pitch))
Player.setVolume(volume: Float(self.volume))
}
var body: some View {
GeometryReader { geometry in
ZStack{
VStack(alignment: .leading) {
Button(action: {
self.heart = !self.heart
self.selectedGraph = "heart"
if(self.heart)
{
Player.playMusic(musicfile: self.selectedMusicFile.file, fileExtension: self.selectedMusicFile.fileExtension)
}
else
{
Player.stopMusic()
self.selectedGraph = ""
}
})
{
Image(self.selectedGraph == "heart" ? "heart" : "heart_disabled")
.resizable()
.frame(width: geometry.size.height*self.iconSize, height: geometry.size.height*self.iconSize)
}
.frame(width: geometry.size.height*self.iconSize, height: geometry.size.height*self.iconSize)
.padding(.bottom, geometry.size.height*(self.iconSpace/2))
Button(action: {
self.showSoundPicker = !self.showSoundPicker
})
{
Image("tone")
.resizable()
.frame(width: geometry.size.height*self.iconSize, height: geometry.size.height*self.iconSize)
}
.frame(width: geometry.size.height*self.iconSize, height: geometry.size.height*self.iconSize)
.padding(.bottom, geometry.size.height*(self.iconSpace/2))
HStack{
SwiftUISlider(
thumbColor: .green,
thumbImage: "musicNote 2",
value: self.$volume
).padding(.horizontal)
Button(action: {
})
{
Image("centerGraph")
.resizable()
.frame(width: geometry.size.width*0.05, height: geometry.size.width*0.05)
}
.frame(width: geometry.size.width*0.03, height: geometry.size.width*0.03)
SwiftUISlider(
thumbColor: .green,
thumbImage: "timerSlider 2",
minValue: 0,
maxValue: 20,
value: self.$pitch
)
.padding(.horizontal)
.frame(width: (geometry.size.width/2)-geometry.size.width*0.05, height: geometry.size.width*0.05)
}
.background(Color(UIColor.lightGray))
.frame(width: geometry.size.width, height: geometry.size.height*0.10)
if(self.showSoundPicker)
{
ChooseSoundView(
musicFiles: self.musicFiles,
selectedMusicFile: self.$selectedMusicFile ,
showSoundPicker: self.$showSoundPicker,
isPlaying: self.selectedGraph != ""
)
.frame(width: geometry.size.width*0.6, height: geometry.size.height*0.7, alignment: .center)
.background(Color.white)
}
}
.frame(maxWidth: geometry.size.width,
maxHeight: geometry.size.height)
.background(Color(UIColor.lightGray))
}
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
struct ChooseSoundView: View {
#State var musicFiles:[SoundModel]
#Binding var selectedMusicFile:SoundModel
#Binding var showSoundPicker:Bool
#State var isPlaying:Bool
var body: some View {
GeometryReader { geometry in
VStack(alignment: .leading)
{
List(self.musicFiles, id: \.name)
{ item in
Image(self.selectedMusicFile.file == item.file ? "radio-button_on" : "radio-button_off")
.resizable()
.frame(width: 15, height: 15)
Button(action: {
print(item.name)
self.selectedMusicFile = item
self.showSoundPicker = false
if(self.isPlaying)
{
// Player.stopMusic()
// Player.playMusic(musicfile: self.selectedMusicFile.file, fileExtension: self.selectedMusicFile.fileExtension)
}
}){
Text(item.name)
.frame(width: geometry.size.width*90,
height: 50.0,
alignment: .leading)
}
.frame(width: geometry.size.width*90, height: 50.0)
}
HStack{
Button(action: {
self.showSoundPicker = false
}){
Text("Done")
.frame(width: geometry.size.width*0.45,
height: 50.0,
alignment: .center)
}
.frame(width: geometry.size.width*0.45, height: 50.0)
Button(action: {
self.showSoundPicker = false
}){
Text("Cancel")
.frame(width: geometry.size.width*0.45,
height: 50.0,
alignment: .center)
}
.frame(width: geometry.size.width*0.45, height: 50.0)
}
.background(Color.white)
}
}
}
}
Player.swift
import Foundation
import AVFoundation
class Player {
private static var breathAudioPlayer:AVAudioPlayer?
private static var audioPlayerEngine = AVAudioEngine()
private static let speedControl = AVAudioUnitVarispeed()
private static var pitchControl = AVAudioUnitTimePitch()
private static var audioPlayerNode = AVAudioPlayerNode()
private static var volume:Float = 1.0
private static func playSounds(soundfile: String) {
if let path = Bundle.main.path(forResource: soundfile, ofType: "m4a"){
do{
breathAudioPlayer = try AVAudioPlayer(contentsOf: URL(fileURLWithPath: path))
breathAudioPlayer?.volume = self.volume
breathAudioPlayer?.prepareToPlay()
breathAudioPlayer?.play()
}catch {
print("Error")
}
}
}
static func playMusic(musicfile: String, fileExtension:String) {
if let path = Bundle.main.path(forResource: musicfile, ofType: fileExtension){
do{
// 1: load the file
let audioPlayFile = try AVAudioFile(forReading: URL(fileURLWithPath: path))
let audioFileBuffer = AVAudioPCMBuffer(pcmFormat: audioPlayFile.fileFormat, frameCapacity: AVAudioFrameCount(audioPlayFile.length))
try? audioPlayFile.read(into: audioFileBuffer!)
// 2: create the audio player
audioPlayerNode = AVAudioPlayerNode()
audioPlayerEngine = AVAudioEngine()
// you can replace mp3 with anything else you like, just make sure you load it from our project
// making sure to clean up the audio hardware to avoid any damage and bugs
audioPlayerNode.stop()
audioPlayerEngine.stop()
audioPlayerEngine.reset()
audioPlayerEngine.attach(audioPlayerNode)
let pitchControl = AVAudioUnitTimePitch()
// assign the speed and pitch
audioPlayerEngine.attach(pitchControl)
audioPlayerEngine.connect(audioPlayerNode, to: pitchControl, format: nil)
audioPlayerEngine.connect(pitchControl, to: audioPlayerEngine.outputNode, format: nil)
audioPlayerNode.scheduleFile(audioPlayFile, at: nil, completionHandler: nil)
// try to start playing the audio
audioPlayerNode.scheduleBuffer(audioFileBuffer!, at: nil, options: .loops, completionHandler: nil)
do {
try audioPlayerEngine.start()
} catch {
print(error)
}
// play the audio
audioPlayerNode.play()
}catch {
print("Error")
}
}
}
static func breathIn() {
// Player.playSounds(soundfile: "breathin")
}
static func breathOut() {
// Player.playSounds(soundfile: "breathout")
}
static func play(musicFile:String, fileExtension:String)
{
Player.playMusic(musicfile: musicFile,fileExtension: fileExtension)
}
static func stopMusic() {
audioPlayerNode.pause()
audioPlayerNode.stop()
}
static func setPitch(pitch:Float) {
pitchControl.pitch = pitch
}
static func setVolume(volume:Float) {
audioPlayerNode.volume = volume
}
}
SwiftUISlider.swift
import Foundation
import SwiftUI
struct SwiftUISlider: UIViewRepresentable {
var onChangeNotification:String = ""
final class Coordinator: NSObject {
// The class property value is a binding: It’s a reference to the SwiftUISlider
// value, which receives a reference to a #State variable value in ContentView.
var value: Binding<Double>
// Create the binding when you initialize the Coordinator
init(value: Binding<Double>) {
self.value = value
}
// Create a valueChanged(_:) action
#objc func valueChanged(_ sender: UISlider) {
self.value.wrappedValue = Double(sender.value)
}
}
var thumbColor: UIColor = .white
var minTrackColor: UIColor?
var maxTrackColor: UIColor?
var thumbImage:String?
var minValue:Float?
var maxValue:Float?
#Binding var value: Double
func makeUIView(context: Context) -> UISlider {
let slider = UISlider(frame: .zero)
slider.thumbTintColor = thumbColor
slider.minimumTrackTintColor = minTrackColor
slider.maximumTrackTintColor = maxTrackColor
slider.value = Float(value)
if(self.minValue != nil)
{
slider.minimumValue = self.minValue!
}
if(self.maxValue != nil)
{
slider.maximumValue = self.maxValue!
}
slider.setThumbImage(UIImage(named: self.thumbImage ?? ""), for: .normal)
slider.setThumbImage(UIImage(named: self.thumbImage ?? ""), for: .focused)
slider.setThumbImage(UIImage(named: self.thumbImage ?? ""), for: .highlighted)
slider.addTarget(
context.coordinator,
action: #selector(Coordinator.valueChanged(_:)),
for: .valueChanged
)
return slider
}
func onValueChange(_ sender: UISlider) {
}
func updateUIView(_ uiView: UISlider, context: Context) {
// Coordinating data between UIView and SwiftUI view
uiView.value = Float(self.value)
}
func makeCoordinator() -> SwiftUISlider.Coordinator {
Coordinator(value: $value)
}
}
SoundModel.swift
import Foundation
import Combine
class SoundModel:ObservableObject, Identifiable
{
#Published var file:String
#Published var name:String
#Published var fileExtension:String
init(file:String, name:String, fileExtension:String) {
self.file = file
self.name = name
self.fileExtension = fileExtension
}
}

Answer 1

Your first problem is that you're not tracking changes of volume/pitch values. To do so move them to a class:
class PlayerSetup: ObservableObject {
#Published var volume:Double = 0.00 {
didSet {
Player.setVolume(volume: Float(self.volume))
}
}
#Published var pitch:Double = 0.0{
didSet {
Player.setPitch(pitch: Float(self.pitch))
}
}
}
Declare in the view:
#ObservedObject var playerSetup = PlayerSetup()
And bind to your views:
SwiftUISlider(
thumbColor: .green,
thumbImage: "musicNote 2",
value: $playerSetup.volume
).padding(.horizontal)
SwiftUISlider(
thumbColor: .green,
thumbImage: "timerSlider 2",
minValue: 0,
maxValue: 20,
value: $playerSetup.pitch
)
it crashes when finish playing the file because try? audioPlayFile.read(into: audioFileBuffer!) fails and your buffer scheduled after the file is empty. and it plays the file for the first time because of scheduleFile. If you wanna loop single file, try calling this function:
static func scheduleNext(audioPlayFile: AVAudioFile) {
audioPlayerNode.scheduleFile(audioPlayFile, at: nil) {
DispatchQueue.main.async {
scheduleNext(audioPlayFile: audioPlayFile)
}
}
}
pitchControl doesn't work because you're using local value when starting playing, just remove the local value declaration.
about to the volume. as you can see in the documentation, This property is implemented only by the AVAudioEnvironmentNode and AVAudioMixerNode class mixers. So you can't use it for a player node, you need to create a mixer node, add it to the chain of nodes, and change it's volume.
Also to clean up nodes code, I advice you to use the following code:
let nodes = [
audioPlayerNode,
pitchControl,
mixerNode,
]
nodes.forEach { node in
audioPlayerEngine.attach(node)
}
zip(nodes, (nodes.dropFirst() + [audioPlayerEngine.outputNode]))
.forEach { firstNode, secondNode in
audioPlayerEngine.connect(firstNode, to: secondNode, format: nil)
}
it connects all nodes one by one.
https://github.com/PhilipDukhov/SwiftUIAudioPlayer/tree/fixes

Answer 2

Main problem of your code that there is mixed view and view model between them. Lot of things that MUST BE in viewModel at the moment located in the View.
View:
struct ContentView: View {
#State var volume:Double = 0.00
#State var pitch:Double = 0.0
#State var musicFiles:[SoundModel] = [SoundModel(file: "metro35", name: "Metronome", fileExtension: "wav"), SoundModel(file: "johnson_tone_down_5min", name: "Johnson", fileExtension: "wav"), SoundModel(file: "sine_140_6s_fade_ogg", name: "Sine wave", fileExtension: "wav")]
#State var selectedMusicFile:SoundModel = SoundModel(file: "sine_140_6s_fade_ogg", name: "Sine wave", fileExtension: "wav")
#State var showSoundPicker = false
#State var selectedGraph = "skin_conductance"
#State var iconSize:CGFloat = 0.124
#State var iconSpace:CGFloat = 0.015
#State var heart = false
init() {
Player.setPitch(pitch: Float(self.pitch))
Player.setVolume(volume: Float(self.volume))
}
view must be:
struct PlayerView: View {
#ObservedObject var viewModel: PlayerViewModel
#State var iconSize:CGFloat = 0.124
#State var iconSpace:CGFloat = 0.015
init() {
// that was wrote here must be moved to init of playerViewModel
}
viewModel your:
import Foundation
import AVFoundation
class Player {
private static var breathAudioPlayer:AVAudioPlayer?
private static var audioPlayerEngine = AVAudioEngine()
private static let speedControl = AVAudioUnitVarispeed()
private static var pitchControl = AVAudioUnitTimePitch()
private static var audioPlayerNode = AVAudioPlayerNode()
private static var volume:Float = 1.0
private static func playSounds(soundfile: String) {
....
ViewModel must be:
import Foundation
import AVFoundation
class PlayerViewModel: ObservableObject {
#Published var volume:Double = 0.00
#Published var pitch:Double = 0.0
#Published var musicFiles:[SoundModel] = [SoundModel(file: "metro35", name: "Metronome", fileExtension: "wav"), SoundModel(file: "johnson_tone_down_5min", name: "Johnson", fileExtension: "wav"), SoundModel(file: "sine_140_6s_fade_ogg", name: "Sine wave", fileExtension: "wav")]
#Published var selectedMusicFile:SoundModel = SoundModel(file: "sine_140_6s_fade_ogg", name: "Sine wave", fileExtension: "wav")
#Published var showSoundPicker = false
#Published var selectedGraph = "skin_conductance"
//#Published var heart = false // SoundViewModel's property
private static var breathAudioPlayer:AVAudioPlayer?
private static var audioPlayerEngine = AVAudioEngine()
private static let speedControl = AVAudioUnitVarispeed()
private static var pitchControl = AVAudioUnitTimePitch()
private static var audioPlayerNode = AVAudioPlayerNode()
private static var volume:Float = 1.0
private static func playSounds(soundfile: String) {
If you will move all of this to proper place, almost sure your code will work better and possibly your problem will be fixed.
at the moment you need to track any changes manually. Your structure of code is the reason of this. You do not need to track this manually because of this is additional useless code.
You need to fix the code structure instead of use "didSet"