Play an audio file using Swift for MacOS - swift

Question

I'm trying to simply play a file (in the main bundle or on the disk) using AVAudioFile, AVAudioEngine and AVAudioPlayerNode.
Here is what I'm doing:
import Foundation
import AppKit
import AudioToolbox
import AVFoundation
struct readFile {
static var arrayFloatValues:[Float] = []
static var points:[CGFloat] = []
}
class AudioAnalisys : NSObject {
class func open_audiofile() {
let audioEngine: AVAudioEngine = AVAudioEngine()
let audioPlayer: AVAudioPlayerNode = AVAudioPlayerNode()
//get where the file is
let url = Bundle.main.url(forResource: "TeamPlaylist", withExtension: "mp3")
//put it in an AVAudioFile
let audioFile = try! AVAudioFile(forReading: url!)
//Get the audio file format
//let format = AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: file.fileFormat.sampleRate, channels: file.fileFormat.channelCount, interleaved: false)
let audioFormat = audioFile.processingFormat
let audioFrameCount = UInt32(audioFile.length)
//how many channels?
print(audioFile.fileFormat.channelCount)
print(audioFrameCount)
//Setup the buffer for audio data
let audioFileBuffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: UInt32(audioFile.length))
//put audio data in the buffer
try! audioFile.read(into: audioFileBuffer!)
//readFile.arrayFloatValues = Array(UnsafeBufferPointer(start: audioFileBuffer!.floatChannelData?[0], count:Int(audioFileBuffer!.frameLength)))
//Init engine and player
let mainMixer = audioEngine.mainMixerNode
audioEngine.attach(audioPlayer)
audioEngine.connect(audioPlayer, to:mainMixer, format: audioFileBuffer!.format)
audioPlayer.scheduleBuffer(audioFileBuffer!, completionHandler: nil)
audioEngine.prepare()
do {
try audioEngine.start()
print("engine started")
} catch let error {
print(error.localizedDescription)
}
audioPlayer.play()
}
}
I can see the channel count, the FrameCount.
I can't hear anything. What am I doing wrong?
Here is what I get in the console:
2
17414784
Optional(0x00006080000006c0)
2018-10-09 21:21:02.161593+0200 spectrum[1668:327525] [AudioHAL_Client] AudioHardware.cpp:666:AudioObjectGetPropertyData: AudioObjectGetPropertyData: no object with given ID 0
engine started
2018-10-09 21:21:02.594136+0200 spectrum[1668:327593] MessageTracer: Falling back to default whitelist

Answer 1

here is the answer:
Can't play file from documents in AVAudioPlayer
which leads to:
import Foundation
import AppKit
import AudioToolbox
import AVFoundation
struct readFile {
static var arrayFloatValues:[Float] = []
static var points:[CGFloat] = []
}
let audioEngine: AVAudioEngine = AVAudioEngine()
let audioPlayer: AVAudioPlayerNode = AVAudioPlayerNode()
class AudioAnalisys : NSObject {
class func open_audiofile() {
//get where the file is
let url = Bundle.main.url(forResource: "TeamPlaylist", withExtension: "mp3")
//put it in an AVAudioFile
let audioFile = try! AVAudioFile(forReading: url!)
//Get the audio file format
//let format = AVAudioFormat(commonFormat: .pcmFormatFloat32, sampleRate: file.fileFormat.sampleRate, channels: file.fileFormat.channelCount, interleaved: false)
let audioFormat = audioFile.processingFormat
let audioFrameCount = UInt32(audioFile.length)
//how many channels?
print(audioFile.fileFormat.channelCount)
print(audioFrameCount)
//Setup the buffer for audio data
let audioFileBuffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: UInt32(audioFile.length))
//put audio data in the buffer
try! audioFile.read(into: audioFileBuffer!)
//readFile.arrayFloatValues = Array(UnsafeBufferPointer(start: audioFileBuffer!.floatChannelData?[0], count:Int(audioFileBuffer!.frameLength)))
//Init engine and player
let mainMixer = audioEngine.mainMixerNode
audioEngine.attach(audioPlayer)
audioEngine.connect(audioPlayer, to:mainMixer, format: audioFileBuffer!.format)
audioPlayer.scheduleBuffer(audioFileBuffer!, completionHandler: nil)
audioEngine.prepare()
do {
try audioEngine.start()
print("engine started")
} catch let error {
print(error.localizedDescription)
}
audioPlayer.play()
}
}