Here is the main method I use:
func synthesize(utteranceString: String, avAudioPCMBufferFormatSettings: [String:Any], usingVoiceIdentifier voiceIdentifier: String, utteranceRate: Float, pitchMultiplier: Float, andSaveAudioFileTo saveToURL: URL, completionHandler: ((_ pcmBuffer: AVAudioPCMBuffer, _ audioFile: AVAudioFile?)->Void)? = nil) {
print("#", #function, "voiceIdentifier: \(voiceIdentifier)", terminator: "\n")
let utterance = AVSpeechUtterance(string: utteranceString)
utterance.rate = utteranceRate
utterance.pitchMultiplier = pitchMultiplier
let voice = AVSpeechSynthesisVoice(identifier: voiceIdentifier) // TODO: Why is this generating a nil?
utterance.voice = voice
synthesizer.write(utterance) { (buffer: AVAudioBuffer) in
print("in closure")
// TODO: Tailor code in this closure to adjust to current device running this app project.
guard let pcmBuffer = buffer as? AVAudioPCMBuffer else {
fatalError("unknown buffer unknown buffer type: \(buffer)")
}
if pcmBuffer.frameLength == 0 {
print("done because buffer frame length equals 0")
} else {
// append buffer to file
if self.audioFile == nil {
print("self.audioFile == nil")
do {
self.audioFile = try AVAudioFile(
forWriting: saveToURL,
settings: pcmBuffer.format.settings,
commonFormat: .pcmFormatInt16,
interleaved: false)
} catch {
print("try AVAudioFile( catch error: \(error.localizedDescription)")
completionHandler?(pcmBuffer, nil)
}
}
do {
try self.audioFile!.write(from: pcmBuffer)
print("!!! 2")
completionHandler?(pcmBuffer, self.audioFile)
} catch {
print("try self.audioFile!.write(from: pcmBuffer) catch error: \(error.localizedDescription)")
completionHandler?(pcmBuffer,nil)
}
}
}
}
