将缓冲区从AVAudioNodeTap写入AVAudioFile (从AVAudioEngine保存录音)

Question

我正在使用AVAudioEngine监控麦克风输入。在AudioEngine停止后，我想将接收到的音频保存到AVAudioFile中以备将来使用。

这是我当前的实现，并且该文件包含数据。它是一个wav文件，但它不是一个可播放的音频文件。我在想，我的格式可能有问题，这是我的方法。

    private enum Setting {
        static let formatID = Int(kAudioFormatLinearPCM)
        static let sampleRate = 16000
        static let numberOfChannels = 1
        static let encoderQuality = AVAudioQuality.min.rawValue
    }

    private let settings: [String: Any] =
        [AVFormatIDKey: Setting.formatID,
         AVSampleRateKey: Setting.sampleRate,
         AVLinearPCMIsFloatKey: true,
         AVNumberOfChannelsKey: Setting.numberOfChannels,
         AVEncoderAudioQualityKey: Setting.encoderQuality]


    func record() {
        let mixer = AVAudioMixerNode()
        audioEngine.attach(mixer)
        let format = AVAudioFormat(settings: settings)
        audioEngine.connect(audioEngine.inputNode, to: mixer, format: audioEngine.inputNode.inputFormat(forBus: 0))
        audioEngine.connect(mixer, to: audioEngine.outputNode, format: format)
        
    guard let destinationURL = FileManager.default.whs_generateWAVFile() else { return }
        do {
            file = try AVAudioFile(forWriting: destinationURL, settings: mixer.outputFormat(forBus: 0).settings, commonFormat: .pcmFormatFloat32, interleaved: true)
            mixer.installTap(onBus: 0, bufferSize: 1024, format: mixer.outputFormat(forBus: 0)) { (buffer, time) in
                do { try self.file?.write(from: buffer); print("Wrote \(buffer)") } catch { print("Error: \(error)") }
            }
            audioEngine.prepare()
            do { try audioEngine.start() } catch { print("Big error:  \(RecordingError.audioEngineStart.description)"); return }
        } catch {
            print("Big Error:  \(RecordingError.audioEngineStart.description), \(error)")
        }
    }

Answer 1

这是因为您尚未关闭要录制到的AVAudioFile。停止引擎时，将file设置为nil，wav文件将可播放。