如何保存麦克风音频输入？ [英] How to save microphone audio input?

问题描述

我需要保存麦克风输入，以便稍后在AudioElement中使用。我这样做以获得麦克风输入：

I need to save microphone input to use later in an AudioElement. I do this to get microphone input:

window.navigator.getUserMedia(audio: true).then((MediaStream stream) {
  # what should go here?
});

我应该如何保存音频？

推荐答案

有很多可怕的愚蠢的例子，你可以在当前浏览器窗口中播放当前的音频录制。是否有这样的用例。对于视频，我可以成像，一个想要构建一个Skype的应用程序，并有一个预览窗口，看看你看起来愚蠢的视频，但音频...

There are many horrible stupid examples out there where you are able to play the current audio recording in the current browser window. Is there ever a use case for this. For video I can imaging that one want to build a Skype like application and have a preview window to see if you look stupid on the video, but audio ...

我发现了一个好的帖子：从麦克风到.WAV ：getUserMedia和Web Audio

I found one good post though: From microphone to .WAV with: getUserMedia and Web Audio

我已经在链接的文章中移植了一部分代码，显示如何获取数据。

I have ported a part of the code in the linked article that shows how to get hold of the data.

import 'dart:html';
import 'dart:async';
import 'dart:web_audio';

void main() {
  window.navigator.getUserMedia(video: true, audio: true).then((MediaStream stream) {
  var context = new AudioContext();
  GainNode volume = context.createGain();
  MediaStreamAudioSourceNode audioInput = context.createMediaStreamSource(stream);
  audioInput.connectNode(volume);

  int bufferSize = 2048;
  ScriptProcessorNode recorder = context.createJavaScriptNode(bufferSize, 2, 2);

  recorder.onAudioProcess.listen((AudioProcessingEvent e) {
    print('recording');
    var left = e.inputBuffer.getChannelData(0);
    var right = e.inputBuffer.getChannelData(1);
    print(left);
    // process Data
  });

  volume.connectNode(recorder);
  recorder.connectNode(context.destination);


/**
 * [How to get a file or blob from an object URL?](http://stackoverflow.com/questions/11876175)
 * [Convert blob URL to normal URL](http://stackoverflow.com/questions/14952052/convert-blob-url-to-normal-url)
 *  Doesn't work as it seems blob urls are not supported in Dart
 */
//    String url = Url.createObjectUrlFromStream(stream);
//    var xhr = new HttpRequest();
//    xhr.responseType = 'blob';
//    xhr.onLoad.listen((ProgressEvent e) {
//      print(xhr.response);
//      var recoveredBlog = xhr.response;
//      var reader = new FileReader();
//
//      reader.onLoad.listen((e) {
//        var blobAsDataUrl = reader.result;
//        reader.readAsDataUrl(blobAsDataUrl);
//      });
//    });
//    xhr.open('GET', url);
//    xhr.send();


/**
 * only for testing purposes
 **/
//    var audio = document.querySelector('audio') as AudioElement;
//    audio.controls = true;
//    audio.src = url;
  });
}

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