iosswiftavaudioengineavaudioplayernode

Saving Audio After Effect in iOS


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


Solution

  • 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()
    
    }