使用Web Audio API录制的音频在开始时被截断

在这个过程中,用户必须说出写在屏幕上的单词,我会分别记录他们说出的每个单词。我的问题是,一些录音在开头或结尾被截断,只留下一部分单词。

以下是我请求访问麦克风的简单代码:

navigator.getUserMedia({
  audio: {
    echoCancellation: false,
    noiseSuppression: false,
    autoGainControl: false
  }
}, this._handleUserMedia.bind(this), () => {
  this.setState({
    recorderAvailable: false
  });
});

_handleUserMedia(stream) {
  this._mediaRecorder = new MediaRecorder(stream);

  this._mediaRecorder.ondataavailable = event => {
    this._mediaBuffer.push(event.data);
  };

  this._mediaRecorder.onstart = () => {
    console.log("Recording started");
    document.getElementById("wordsStage").style.color = "red";
  }

  this._mediaRecorder.onstop = () => {
    // Create an URL to download the recording
    this.state.results[this.state.currentWordIdx].recordingUrl = URL.createObjectURL(new Blob(this._mediaBuffer));

    // Reinitialize the buffer for next recording
    this._mediaBuffer = [];
    console.log("Recording stopped");
    document.getElementById("wordsStage").style.color = "black";

    this._gotoNextWord();
  };

  this._gotoNextWord();
}

这是我开始/停止录制的代码:

_registerAnswer(isCorrect) {
  this.state.results.push({
    word: this.props.data.words[this._currentWordIdx],
    isCorrect
  });

  this._mediaRecorder && this._mediaRecorder.state === "recording" && this._mediaRecorder.stop();

  // mediaRecorder.onstop handler will trigger the next word once the recording has been saved
}

_gotoNextWord() {
  const dataSource = this.state.isDoingExamples ? this.props.data.examples : this.props.data.words;
  if (this._currentWordIdx < dataSource.length - 1) {
    // Starts the recording
    !this.state.isDoingExamples && this._mediaRecorder && this._mediaRecorder.start(500);

    // displays the concentration point
    this._displayWordOnStage(null, true);

    // displays the current word after the concentration's point duration elapsed
    setTimeout(() => this._displayWordOnStage(++this._currentWordIdx), Shared.FocusPointDurationInMs);
  } else if (this.state.isDoingExamples) {
    this._currentWordIdx = -1;
    this.setState({
        isDoingExamples: false
      },
      this._gotoNextWord
    );
  } else {
    this._finishTraining();
  }
}

here

编辑:

this blog post 表示在Chrome中 noiseSuppression 虽然约束处于启用状态,但不受支持,因此无法将其禁用。较新版本的Chrome确实有此限制,但嵌入Electron的版本没有此限制:使用时未列出此限制 navigator.mediaDevices.getSupportedConstraints(); . 这可能就是大多数单词在开头被截断的原因吧?
我试过用电子,但没用反应,没关系,所以不可能是。。。

编辑3 :我将Electron更新为最新版本(2.0.3),其中包括Chrome 61.0.3163.100。我仍然有这个问题。