Swift + AVAudioRecorder records very quietly - ios

Question

I have built an iOS App in Swift that records audio clips, these clips are then sent up to the server. Every recording I make is very quiet.
Initially I thought my problems were similar to this question on Stack Overflow - but after trying this solution, my recordings are still very quiet.
Routing the audio through the speaker does not make the recordings any louder, as is suggested here:
https://stackoverflow.com/a/5662478/1037617
Note that its not playback on the device that is an issue. The issue is that the recordings are too quiet. I have tested the Microphone itself, and it is fine.
This is the best waveform I can produce, and this is almost shouting into the Microphone. As you can see, the waveform recorded is very quiet:
Is there any way of getting my iOS App to record at a louder volume?
This is the code I am using to record the audio clips:
let recorderSettings=[
AVFormatIDKey : kAudioFormatLinearPCM,
AVEncoderAudioQualityKey : AVAudioQuality.Max.rawValue,
AVEncoderBitRateKey : 128000,
AVNumberOfChannelsKey : 1,
AVSampleRateKey : 44100.0
]
let session: AVAudioSession = AVAudioSession.sharedInstance()
var error: NSError?
if session.respondsToSelector("requestRecordPermission:") {
AVAudioSession.sharedInstance().requestRecordPermission( { (granted:Bool) -> Void in
if !granted {
println("permission not granted")
}else{
println("permission granted")
if !session.setCategory(AVAudioSessionCategoryRecord, error: &error) { // also tried PlaybackAndRecord
println("could not set sesssion category")
if let e = error {
println(e.localizedDescription)
}
}
if !session.overrideOutputAudioPort(AVAudioSessionPortOverride.Speaker, error: &error) {
println("could not override output audio")
if let e = error {
println(e.localizedDescription)
}
}
if !session.setActive(true, error: &error) {
println("could not make active")
if let e = error {
println(e.localizedDescription)
}
}
self.currentFilename = "xxxx.wav"
let dirPaths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)
let docsDir: AnyObject=dirPaths[0]
self.recordedFilePath = docsDir.stringByAppendingPathComponent(self.currentFilename)
self.recordedFileURL = NSURL(fileURLWithPath: self.recordedFilePath)
self.recorder = AVAudioRecorder(URL:self.recordedFileURL, settings: self.recorderSettings, error: &error)
if let e = error {
println(e)
println(e.localizedDescription)
var err = NSError(domain: NSOSStatusErrorDomain, code: e.code, userInfo: nil)
println(err.description)
}else{
self.recorder?.delegate = self
self.recorder?.meteringEnabled = true
self.recorder?.prepareToRecord()
self.recorder?.record()
self.meterTimer = NSTimer.scheduledTimerWithTimeInterval(0.1,
target: self,
selector: "updateRecordAudioMeter:",
userInfo: nil,
repeats: true)
}
}
})
}

Answer 1

When recording audio, set the audio session to AVAudioSessionCategoryPlayAndRecord or just AVAudioSessionCategoryRecord. When you're done, set it back to just AVAudioSessionCategoryPlayback.

Answer 2

You need to set the AVAudioSession category back to AVAudioSessionCategoryPlayback after recording