Basically, I am trying to play AAC(with ADTS header) streams with AudioEngine through websockets (I am using StarScream). I play these audio in real time and there are glitches between the audio packets while playing. These are the steps I tried:
- Received data from WebSocket
extension ViewController: WebSocketDelegate {
func didReceive(event: WebSocketEvent, client: WebSocket) {
switch event {
case .binary(let data):
// Here is the AAC Stream. I store them in a buffer (NSMutableData)
default:
break
}
}
}
- Parse the AAC (AAC to PCM)
Saved the data to audio.aac using FileHandle and decoded it using AVAudioFile
func decodeAACTOPCM(aac: Data) -> AVAudioPCMBuffer? {
self.fileHelper.createFile(name: "audio.aac")
self.fileHelper.writeFile(data: aac)
let url = URL(fileURLWithPath: fileHelper.path)
do {
let audioFile = try AVAudioFile(forReading: url)
guard let buffer = AVAudioPCMBuffer(pcmFormat: audioFile.processingFormat, frameCapacity: .init(audioFile.length * 3)) else {
return nil
}
try audioFile.read(into: buffer)
buffer.frameLength = buffer.frameCapacity
print("Buffer size \(buffer.frameLength)")
return buffer
} catch {
print(error)
return nil
}
}
- Play the PCM Data
func playPCM(_ pcm: AVAudioPCMBuffer) {
audioFilePlayer.scheduleBuffer(pcm, at: nil, options: .interrupts, completionHandler: nil)
}
- The final result audio has some glitch between each audio packets. The issue was similar to this.. https://storage.googleapis.com/webfundamentals-assets/videos/gap.webm
Any suggestions on what I did wrong is appreciated.
Thank you!
