MediaRecorder

MediaRecorder 是 MediaStream Recording API 提供的用来进行媒体轻松录制的接口, 他需要通过调用 MediaRecorder() 构造方法进行实例化.

MediaRecorder.MediaRecorder()

    创建一个新的MediaRecorder对象,对指定的MediaStream 对象进行录制,支持的配置项包括设置容器的MIME 类型 (例如"video/webm" 或者 "video/mp4")和音频及视频的码率或者二者同用一个码率

MediaRecorder.mimeType (en-US) 只读

    返回 MediaRecorder 对象创建时选择器选择的录制容器的 MIME type

MediaRecorder.state (en-US) 只读

    返回录制对象MediaRecorder  的当前状态(闲置中,录制中或者暂停 ) (inactive, recording, or paused.)

MediaRecorder.stream (en-US) 只读

    返回录制器对象 MediaRecorder 创建时构造函数传入的stream对象

MediaRecorder.ignoreMutedMedia (en-US)

    用以指定 MediaRecorder是否录制无声的输入源. 如果这个属性是false. 录制器对象MediaRecorder  会录制无声的音频或者黑屏的视频, 默认值是false

MediaRecorder.videoBitsPerSecond (en-US) 只读

返回视频采用的编码比率. 它可能和构造函数的设置比率不同.  (if it was provided).

MediaRecorder.audioBitsPerSecond 只读

返回音频采用的编码比率,它可能和构造函数中设置的比率不同. (if it was provided).

MediaRecorder.isTypeSupported() (en-US)

返回一个Boolean (en-US) 值,来表示设置的MIME type 是否被当前用户的设备支持.

MediaRecorder.pause()

暂停媒体录制

MediaRecorder.requestData() (en-US)

请求一个从开始到当前接收到的,存储为Blob类型的录制内容. (或者是返回从上一次调用requestData() 方法之后到现在的内容).  调用这个方法后,录制将会继续进行,但是会创建一个新的Blob对象

MediaRecorder.resume() (en-US)

继续录制之前被暂停的录制动作.

MediaRecorder.start() (en-US)

开始录制媒体,这个方法调用时可以通过给timeslice参数设置一个毫秒值,如果设置这个毫秒值,那么录制的媒体会按照你设置的值进行分割成一个个单独的区块, 而不是以默认的方式录制一个非常大的整块内容.

MediaRecorder.stop() (en-US)

停止录制. 同时触发dataavailable事件,返回一个存储Blob内容的录制数据.之后不再记录

MediaRecorder.isTypeSupported()

静态方法，判断给定的MIME类型是否支持。返回Boolean (en-US)类型的值。

MediaRecorder.ondataavailable

调用它用来处理 dataavailable 事件, 该事件可用于获取录制的媒体资源 (在事件的 data 属性中会提供一个可用的 Blob 对象.)

MediaRecorder.onerror (en-US)

An EventHandler (en-US) called to handle the recordingerror event, including reporting errors that arise with media recording. These are fatal errors that stop recording.

MediaRecorder.onpause (en-US)

用来处理 pause (en-US) 事件, 该事件在媒体暂停录制时触发（MediaRecorder.pause()）.

MediaRecorder.onresume (en-US)

用来处理 resume 事件, 该事件在暂停后回复录制视频时触发（MediaRecorder.resume() (en-US)）.

MediaRecorder.onstart (en-US)

用来处理 start 事件, 该事件在媒体开始录制时触发（MediaRecorder.start() (en-US)）.

MediaRecorder.onstop (en-US)

用来处理 stop 事件, 该事件会在媒体录制结束时、媒体流（MediaStream）结束时、或者调用MediaRecorder.stop() (en-US) 方法后触发.

Listen to these events using addEventListener() or by assigning an event listener to the oneventname property of this interface.

error

Fired when an error occurs: for example because recording wasn't allowed or was attempted using an unsupported codec.
Also available via the onerror property.

if (navigator.mediaDevices) {
  console.log('getUserMedia supported.');

  var constraints = { audio: true };
  var chunks = [];

  navigator.mediaDevices.getUserMedia(constraints)
  .then(function(stream) {

    var mediaRecorder = new MediaRecorder(stream);

    visualize(stream);

    record.onclick = function() {
      mediaRecorder.start();
      console.log(mediaRecorder.state);
      console.log("recorder started");
      record.style.background = "red";
      record.style.color = "black";
    }

    stop.onclick = function() {
      mediaRecorder.stop();
      console.log(mediaRecorder.state);
      console.log("recorder stopped");
      record.style.background = "";
      record.style.color = "";
    }

    mediaRecorder.onstop = function(e) {
      console.log("data available after MediaRecorder.stop() called.");

      var clipName = prompt('Enter a name for your sound clip');

      var clipContainer = document.createElement('article');
      var clipLabel = document.createElement('p');
      var audio = document.createElement('audio');
      var deleteButton = document.createElement('button');

      clipContainer.classList.add('clip');
      audio.setAttribute('controls', '');
      deleteButton.innerHTML = "Delete";
      clipLabel.innerHTML = clipName;

      clipContainer.appendChild(audio);
      clipContainer.appendChild(clipLabel);
      clipContainer.appendChild(deleteButton);
      soundClips.appendChild(clipContainer);

      audio.controls = true;
      var blob = new Blob(chunks, { 'type' : 'audio/ogg; codecs=opus' });
      chunks = [];
      var audioURL = URL.createObjectURL(blob);
      audio.src = audioURL;
      console.log("recorder stopped");

      deleteButton.onclick = function(e) {
        evtTgt = e.target;
        evtTgt.parentNode.parentNode.removeChild(evtTgt.parentNode);
      }
    }

    mediaRecorder.ondataavailable = function(e) {
      chunks.push(e.data);
    }
  })
  .catch(function(err) {
    console.log('The following error occured: ' + err);
  })
}

• [1] The initial Firefox OS implementation only supported audio recording.

• Using the MediaRecorder API
• Web Dictaphone: MediaRecorder + getUserMedia + Web Audio API visualization demo, by Chris Mills (source on Github.)
• Recording a media element
• simpl.info MediaStream Recording demo, by Sam Dutton.
• navigator.mediaDevices.getUserMedia (en-US)
• FingerSpell: Sign Language Fingerspelling practice using MediaDevices and the MediaStream Recording API to create and download recordings, MediaRecorder API supported desktop browsers only (source on GitHub)