參考 :

http://air.ghost.io/recording-to-an-audio-file-using-html5-and-js/ (html5 基礎)

https://github.com/muaz-khan/RecordRTC

https://github.com/webpack-contrib/worker-loader

https://github.com/webpack-contrib/file-loader

https://github.com/muaz-khan/RecordRTC/issues/31 (wav 太大的解決方案)

https://github.com/muaz-khan/Ffmpeg.js/blob/master/wav-to-ogg.html#L209 ( ftmpeg wav to ogg 壓縮方案 )

http://audior.ec/blog/recording-mp3-using-only-html5-and-javascript-recordmp3-js/ (wav to mp3 壓縮方案, 超小, 聲音也差.., 可以使用 lamejs 比較新)

使用插件

npm install recordrtc

npm install --save-dev file-loader

npm install --save-dev worker-loader

要使用 file,worker loading 需要在 tsconfig.app.json 加上 "node"

  "compilerOptions": {
 
"types": [
      "node"
    ]
  },

startRecord() {
  navigator.mediaDevices.getUserMedia({ audio: true }).then((stream) => {
    let recordRTC = RecordRTC(stream, {
      type: ‘audio‘,
      recorderType: RecordRTC.StereoAudioRecorder,
      disableLogs: 
 
true 
      //leftChannel: true,
      //numberOfAudioChannels: 1 // or leftChannel:true
    });
    recordRTC.startRecording();
    this.recordRTC = recordRTC;
    this.stream = stream;
  }).catch(() => {
    console.log(‘user no allow‘);
  });
}

通過 html5 的 navigator.mediaDevices.getUserMedia 獲取用戶的 permission, 然後就可以獲取到聲音了

通過 RecordRTC 來做錄制. 如果是要 to mp3 的話, 可以選擇單聲道 (不過我試過 to mp3 效果聲音效果不好, 所以最好用了 .ogg)

 stop() {
    let recordRTC = this.recordRTC;
    recordRTC.stopRecording(() => {    
      // 關閉 html5 navigator.mediaDevices.getUserMedia
      var track = this.stream.getTracks()[0]; // 0 是因為我們只有一個 track, 是可以 track 2 個的, 聲音和影像
      track.stop();

      // ff 可以 skip 掉 fileReader, 直接拿 recordRTC.blob new File 也可以, 因為 ff 返回的就是 ogg 了 
      // 下面是針對 chrome 返回的是 wav, 很大, 所以使用 ffmpeg 壓縮去 ogg 
      let fileReader = new FileReader();

      fileReader.onload = () => {
        recordRTC.clearRecordedData(); // reader 讀出來後就可以釋放 recordRTC 了. 

        //壓縮是很慢的, 所以要另開一個線程
        var WorkerConstructor = require("worker-loader!./worker2.js"); 
        var worker = new WorkerConstructor();

        worker.onmessage = (e) => {
          var result = e.data[0];
          // edge 不可以跑哦, 只有 chrome and ff ok 
          var blob = new File([result.data], ‘whatever.ogg‘, {
            type: ‘audio/ogg‘
          });
          
          let formData = new FormData();
          formData.append(‘uploadFile‘, blob, ‘whatever.ogg‘);

          // 上傳
          this.http.post(‘/api/uploadFile‘, formData).subscribe(() => {
            console.log(‘done‘);
          });

          // 做成 audio 
          let audio = new Audio();
          audio.controls = true;
          let url = window.URL.createObjectURL(blob);
          
          audio.src = url;
          let recordMp3Container = document.getElementById(‘recordmp3-container‘);
          recordMp3Container.appendChild(audio);
          audio.play();

          // 關閉 worker 
          worker.terminate(); 
        };
    
        worker.postMessage(fileReader.result);
      };

      fileReader.readAsArrayBuffer(recordRTC.blob); 
    });
  }

worker2.js

let url = require("file-loader!./ffmpeg_asm.js");  

self.importScripts(url);

let print = () => { };
self.onmessage = (event) => {
    let blob = event.data;
    let result = ffmpeg_run({
        print: print,
        printErr: print,
        files: [
            {
                data: new Uint8Array(blob),
                name: "whatever.wav"
            }
        ],
        arguments: ‘-i whatever.wav -c:a vorbis -b:a 4800k -strict experimental output.ogg‘.split(‘ ‘)
    });
    self.postMessage(result);
};

關鍵就是調用了 ffmpeg_run

https://archive.org/download/ffmpeg_asm/ffmpeg_asm.js

這個轉換器 18mb 非常大哦. 不過只要下載一次, 所以 ok 啦.

wav to mp3

步驟和上面一下, 使用單聲道.

然後 worker 用下面這個

//var url = require("file-loader!./lame.all.js");
var url = require("file-loader!lamejs/lame.all.js");  

self.importScripts(url);

self.onmessage = function (e) {
    let stream = e.data.stream;
    let streamArray = new Int16Array(stream);
    streamArray = streamArray.slice(50); //去掉一開始的雜音
    let buffer = [];
    let mp3encoder = new lamejs.Mp3Encoder(1, 44100, 128);

    let mp3Data = mp3encoder.encodeBuffer(streamArray);
    buffer.push(mp3Data);
    mp3Data = mp3encoder.flush(); //獲取最後一個 part
    buffer.push(mp3Data);
    let blob = new Blob(buffer, { type: ‘audio/mp3‘ });
    var workerResult = {
        stream: blob
    };
    self.postMessage(workerResult);
}

調用 lamejs 去壓縮.

.

錄音 voice record