从AVAudioNodeTap向AVAudioFile写入缓冲区保存来自AVAudioEngine的音频记录

问题描述

我正在使用AVAudioEngine监视麦克风输入。 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，文件中确实包含数据。它是一个wav文件，但不是可播放的音频文件。我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)")
        }
    }
   

解决方法

这是因为您尚未关闭要录制到的 AVAudioFile。停止引擎时将文件设置为 nil 即可播放 wav 文件。