Saving Audio After Effect in iOS - ios

Question

i am developing an applicatoin so that people can record and change their voices thru app and share it . Basically i so many things and now its time to ask you to help . Here is my play function which plays recorded audio file and adds effects on it .
private func playAudio(pitch : Float, rate: Float, reverb: Float, echo: Float) {
// Initialize variables
audioEngine = AVAudioEngine()
audioPlayerNode = AVAudioPlayerNode()
audioEngine.attachNode(audioPlayerNode)
// Setting the pitch
let pitchEffect = AVAudioUnitTimePitch()
pitchEffect.pitch = pitch
audioEngine.attachNode(pitchEffect)
// Setting the platback-rate
let playbackRateEffect = AVAudioUnitVarispeed()
playbackRateEffect.rate = rate
audioEngine.attachNode(playbackRateEffect)
// Setting the reverb effect
let reverbEffect = AVAudioUnitReverb()
reverbEffect.loadFactoryPreset(AVAudioUnitReverbPreset.Cathedral)
reverbEffect.wetDryMix = reverb
audioEngine.attachNode(reverbEffect)
// Setting the echo effect on a specific interval
let echoEffect = AVAudioUnitDelay()
echoEffect.delayTime = NSTimeInterval(echo)
audioEngine.attachNode(echoEffect)
// Chain all these up, ending with the output
audioEngine.connect(audioPlayerNode, to: playbackRateEffect, format: nil)
audioEngine.connect(playbackRateEffect, to: pitchEffect, format: nil)
audioEngine.connect(pitchEffect, to: reverbEffect, format: nil)
audioEngine.connect(reverbEffect, to: echoEffect, format: nil)
audioEngine.connect(echoEffect, to: audioEngine.outputNode, format: nil)
audioPlayerNode.stop()
let length = 4000
let buffer = AVAudioPCMBuffer(PCMFormat: audioPlayerNode.outputFormatForBus(0),frameCapacity:AVAudioFrameCount(length))
buffer.frameLength = AVAudioFrameCount(length)
try! audioEngine.start()
let dirPaths: AnyObject = NSSearchPathForDirectoriesInDomains( NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0]
let tmpFileUrl: NSURL = NSURL.fileURLWithPath(dirPaths.stringByAppendingPathComponent("effectedSound.m4a"))
do{
print(dirPaths)
let settings = [AVFormatIDKey: NSNumber(unsignedInt: kAudioFormatMPEG4AAC), AVSampleRateKey: NSNumber(integer: 44100), AVNumberOfChannelsKey: NSNumber(integer: 2)]
self.newAudio = try AVAudioFile(forWriting: tmpFileUrl, settings: settings)
audioEngine.outputNode.installTapOnBus(0, bufferSize: (AVAudioFrameCount(self.player!.duration)), format: self.audioPlayerNode.outputFormatForBus(0)){
(buffer: AVAudioPCMBuffer!, time: AVAudioTime!) in
print(self.newAudio.length)
print("=====================")
print(self.audioFile.length)
print("**************************")
if (self.newAudio.length) < (self.audioFile.length){
do{
//print(buffer)
try self.newAudio.writeFromBuffer(buffer)
}catch _{
print("Problem Writing Buffer")
}
}else{
self.audioPlayerNode.removeTapOnBus(0)
}
}
}catch _{
print("Problem")
}
audioPlayerNode.play()
}
I guess the problem is i am installTapOnBus to audioPlayerNode but the effected audio is on audioEngine.outputNode .However i tried to installTapOnBus to audioEngine.outputNode but it gives me error.Also i've tried to connect effects to audioEngine.mixerNode but it also not a solution . So that do you have any experiences on saving effected audio file ? How can i get this effected audio?
Any help is appreciated
Thank you

Answer 1

Here it is my solution to question :
func playAndRecord(pitch : Float, rate: Float, reverb: Float, echo: Float) {
// Initialize variables
// These are global variables . if you want you can just (let audioEngine = etc ..) init here these variables
audioEngine = AVAudioEngine()
audioPlayerNode = AVAudioPlayerNode()
audioEngine.attachNode(audioPlayerNode)
playerB = AVAudioPlayerNode()
audioEngine.attachNode(playerB)
// Setting the pitch
let pitchEffect = AVAudioUnitTimePitch()
pitchEffect.pitch = pitch
audioEngine.attachNode(pitchEffect)
// Setting the platback-rate
let playbackRateEffect = AVAudioUnitVarispeed()
playbackRateEffect.rate = rate
audioEngine.attachNode(playbackRateEffect)
// Setting the reverb effect
let reverbEffect = AVAudioUnitReverb()
reverbEffect.loadFactoryPreset(AVAudioUnitReverbPreset.Cathedral)
reverbEffect.wetDryMix = reverb
audioEngine.attachNode(reverbEffect)
// Setting the echo effect on a specific interval
let echoEffect = AVAudioUnitDelay()
echoEffect.delayTime = NSTimeInterval(echo)
audioEngine.attachNode(echoEffect)
// Chain all these up, ending with the output
audioEngine.connect(audioPlayerNode, to: playbackRateEffect, format: nil)
audioEngine.connect(playbackRateEffect, to: pitchEffect, format: nil)
audioEngine.connect(pitchEffect, to: reverbEffect, format: nil)
audioEngine.connect(reverbEffect, to: echoEffect, format: nil)
audioEngine.connect(echoEffect, to: audioEngine.mainMixerNode, format: nil)
// Good practice to stop before starting
audioPlayerNode.stop()
// Play the audio file
// this player is also a global variable AvAudioPlayer
if(player != nil){
player?.stop()
}
// audioFile here is our original audio
audioPlayerNode.scheduleFile(audioFile, atTime: nil, completionHandler: {
print("Complete")
})
try! audioEngine.start()
let dirPaths: AnyObject = NSSearchPathForDirectoriesInDomains( NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0]
let tmpFileUrl: NSURL = NSURL.fileURLWithPath(dirPaths.stringByAppendingPathComponent("effectedSound2.m4a"))
//Save the tmpFileUrl into global varibale to not lose it (not important if you want to do something else)
filteredOutputURL = tmpFileUrl
do{
print(dirPaths)
self.newAudio = try! AVAudioFile(forWriting: tmpFileUrl, settings: [
AVFormatIDKey: NSNumber(unsignedInt:kAudioFormatAppleLossless),
AVEncoderAudioQualityKey : AVAudioQuality.Low.rawValue,
AVEncoderBitRateKey : 320000,
AVNumberOfChannelsKey: 2,
AVSampleRateKey : 44100.0
])
let length = self.audioFile.length
audioEngine.mainMixerNode.installTapOnBus(0, bufferSize: 1024, format: self.audioEngine.mainMixerNode.inputFormatForBus(0)) {
(buffer: AVAudioPCMBuffer!, time: AVAudioTime!) -> Void in
print(self.newAudio.length)
print("=====================")
print(length)
print("**************************")
if (self.newAudio.length) < length {//Let us know when to stop saving the file, otherwise saving infinitely
do{
//print(buffer)
try self.newAudio.writeFromBuffer(buffer)
}catch _{
print("Problem Writing Buffer")
}
}else{
self.audioEngine.mainMixerNode.removeTapOnBus(0)//if we dont remove it, will keep on tapping infinitely
//DO WHAT YOU WANT TO DO HERE WITH EFFECTED AUDIO
}
}
}catch _{
print("Problem")
}
audioPlayerNode.play()
}

Answer 2

This doesn't seem to be hooked up correctly. I'm just learning all this myself, but I found that the effects are correctly added when you connect them to a mixer node. Also, you'll want to tap the mixer, not the engine output node. I've just copied your code and made a few modifications to take this into account.
private func playAudio(pitch : Float, rate: Float, reverb: Float, echo: Float) {
// Initialize variables
audioEngine = AVAudioEngine()
audioPlayerNode = AVAudioPlayerNode()
audioEngine.attachNode(audioPlayerNode)
// Setting the pitch
let pitchEffect = AVAudioUnitTimePitch()
pitchEffect.pitch = pitch
audioEngine.attachNode(pitchEffect)
// Setting the playback-rate
let playbackRateEffect = AVAudioUnitVarispeed()
playbackRateEffect.rate = rate
audioEngine.attachNode(playbackRateEffect)
// Setting the reverb effect
let reverbEffect = AVAudioUnitReverb()
reverbEffect.loadFactoryPreset(AVAudioUnitReverbPreset.Cathedral)
reverbEffect.wetDryMix = reverb
audioEngine.attachNode(reverbEffect)
// Setting the echo effect on a specific interval
let echoEffect = AVAudioUnitDelay()
echoEffect.delayTime = NSTimeInterval(echo)
audioEngine.attachNode(echoEffect)
// Set up a mixer node
let audioMixer = AVAudioMixerNode()
audioEngine.attachNode(audioMixer)
// Chain all these up, ending with the output
audioEngine.connect(audioPlayerNode, to: playbackRateEffect, format: nil)
audioEngine.connect(playbackRateEffect, to: pitchEffect, format: nil)
audioEngine.connect(pitchEffect, to: reverbEffect, format: nil)
audioEngine.connect(reverbEffect, to: echoEffect, format: nil)
audioEngine.connect(echoEffect, to: audioMixer, format: nil)
audioEngine.connect(audioMixer, to: audioEngine.outputNode, format: nil)
audioPlayerNode.stop()
let length = 4000
let buffer = AVAudioPCMBuffer(PCMFormat: audioPlayerNode.outputFormatForBus(0),frameCapacity:AVAudioFrameCount(length))
buffer.frameLength = AVAudioFrameCount(length)
try! audioEngine.start()
let dirPaths: AnyObject = NSSearchPathForDirectoriesInDomains( NSSearchPathDirectory.DocumentDirectory, NSSearchPathDomainMask.UserDomainMask, true)[0]
let tmpFileUrl: NSURL = NSURL.fileURLWithPath(dirPaths.stringByAppendingPathComponent("effectedSound.m4a"))
do{
print(dirPaths)
let settings = [AVFormatIDKey: NSNumber(unsignedInt: kAudioFormatMPEG4AAC), AVSampleRateKey: NSNumber(integer: 44100), AVNumberOfChannelsKey: NSNumber(integer: 2)]
self.newAudio = try AVAudioFile(forWriting: tmpFileUrl, settings: settings)
audioMixer.installTapOnBus(0, bufferSize: (AVAudioFrameCount(self.player!.duration)), format: self.audioMixer.outputFormatForBus(0)){
(buffer: AVAudioPCMBuffer!, time: AVAudioTime!) in
print(self.newAudio.length)
print("=====================")
print(self.audioFile.length)
print("**************************")
if (self.newAudio.length) < (self.audioFile.length){
do{
//print(buffer)
try self.newAudio.writeFromBuffer(buffer)
}catch _{
print("Problem Writing Buffer")
}
}else{
self.audioMixer.removeTapOnBus(0)
}
}
}catch _{
print("Problem")
}
audioPlayerNode.play()
}
I also had trouble getting the file formatted properly. I finally got it working when I changed my path of the output file from m4a to caf. One other suggestion is to not have nil for the format parameter. I used the audioFile.processingFormat. I hope this helps. My audio effects/mixing is functional, although I did not chain my effects. So feel free to ask questions.

Answer 3

just change the parameter unsigned int from kAudioFormatMPEG4AAC to kAudioFormatLinearPCM and also change file type to .caf it will sure helpfull my friend

Answer 4

For anyone who have the problem of having to play the audio file TWICE to save it, i just added the following line at the respective place and it solved my problem.
might help someone in the future.
P.S: I used the EXACT same code as the checked Answer from above, just added this one line and solved my problem.
//Do what you want to do here with effected Audio
self.newAudio = try! AVAudioFile(forReading: tmpFileUrl)

Answer 5

We can use a certain way to adjust the voices such as: aliens, men, old people, robots, children, ....
and has a playback counter
var delayInSecond: Double = 0
if let lastRenderTime = self.audioPlayerNode.lastRenderTime, let playerTime = self.audioPlayerNode.playerTime(forNodeTime: lastRenderTime)
{
if let rate = rate {
delayInSecond = Double(self.audioFile.length - playerTime.sampleTime) / Double(self.audioFile.processingFormat.sampleRate) / Double(rate)
}else{
delayInSecond = Double(self.audioFile.length - playerTime.sampleTime) / Double(self.audioFile.processingFormat.sampleRate)
}
//schedule a stop timer for when audio finishes playing
self.stopTimer = Timer(timeInterval: delayInSecond, target: self, selector: #selector(stopPlay), userInfo: nil, repeats: true)
RunLoop.main.add(self.stopTimer, forMode: .default)
}

Answer 6

I got this after I add
self.newAudio = try! AVAudioFile(forReading: tmpFileUrl)
return like this
Error
Domain=com.apple.coreaudio.avfaudio
Code=1685348671 "(null)" UserInfo={failed
call=ExtAudioFileOpenURL((CFURLRef)fileUR
L, &_extAudioFile)}