Web音頻API-捕獲音頻-禁用低通濾波器

Question

我使用了本教程： http : //typedarray.org/from-microphone-to-wav-with-getusermedia-and-web-audio/

以及這個實時演示頁面： http : //typedarray.org/wp-content/projects/WebAudioRecorder/

創建我的高頻分析儀。

我的問題是，默認情況下，Web Audio API會切斷高頻。

當我錄制WAV並播放10000hz信號時，wav包含我的頻率。

如果我播放17000Hz信號，WAV將不包含我的頻率。

如何禁用低通濾波器？

碼：

function success(e){
    // creates the audio context
    audioContext = window.AudioContext || window.webkitAudioContext;
    context = new audioContext();

    // creates a gain node
    volume = context.createGain();

    // creates an audio node from the microphone incoming stream
    audioInput = context.createMediaStreamSource(e);

    // connect the stream to the gain node
    audioInput.connect(volume);

    /* From the spec: This value controls how frequently the audioprocess event is 
    dispatched and how many sample-frames need to be processed each call. 
    Lower values for buffer size will result in a lower (better) latency. 
    Higher values will be necessary to avoid audio breakup and glitches */
    var bufferSize = 2048;
    recorder = context.createJavaScriptNode(bufferSize, 2, 2);

    recorder.onaudioprocess = function(e){
        console.log ('recording');
        var left = e.inputBuffer.getChannelData (0);
        var right = e.inputBuffer.getChannelData (1);
        // we clone the samples
        leftchannel.push (new Float32Array (left));
        rightchannel.push (new Float32Array (right));
        recordingLength += bufferSize;
    }

    // we connect the recorder
    volume.connect (recorder);
    recorder.connect (context.destination); 
}

Answer 1

這在getUserMedia ，而不在Web Audio API中。 默認情況下， getUserMedia提供給您的MediaStream包含已經（取決於瀏覽器）的數據：-取消了回聲-抑制了噪音-應用了自動增益補償

您可以使用約束禁用這些約束（例如，對於Firefox）：

navigator.mediaDevices.getUserMedia({audio: { echoCancellation: false, mozNoiseSuppression: false, mozAutoGainControl: false });

我們目前正在對這些屬性進行標准化，但尚未完成。