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MediaRecorder

The MediaRecorder interface of the MediaStream Recording API provides functionality to easily record media. It is created using the MediaRecorder() constructor.

EventTarget MediaRecorder

Constructor

MediaRecorder()

Creates a new MediaRecorder object, given a MediaStream to record. Options are available to do things like set the container's MIME type (such as "video/webm" or "video/mp4") and the bit rates of the audio and video tracks or a single overall bit rate.

Instance properties

MediaRecorder.mimeType Read only

Returns the MIME type that was selected as the recording container for the MediaRecorder object when it was created.

MediaRecorder.state Read only

Returns the current state of the MediaRecorder object (inactive, recording, or paused.)

MediaRecorder.stream Read only

Returns the stream that was passed into the constructor when the MediaRecorder was created.

MediaRecorder.videoBitsPerSecond Read only

Returns the video encoding bit rate in use. This may differ from the bit rate specified in the constructor (if it was provided).

MediaRecorder.audioBitsPerSecond Read only

Returns the audio encoding bit rate in use. This may differ from the bit rate specified in the constructor (if it was provided).

Static methods

MediaRecorder.isTypeSupported()

A static method which returns a true or false value indicating if the given MIME media type is supported by the current user agent.

Instance methods

MediaRecorder.pause()

Pauses the recording of media.

MediaRecorder.requestData()

Requests a Blob containing the saved data received thus far (or since the last time requestData() was called. After calling this method, recording continues, but in a new Blob.

MediaRecorder.resume()

Resumes recording of media after having been paused.

MediaRecorder.start()

Begins recording media; this method can optionally be passed a timeslice argument with a value in milliseconds. If this is specified, the media will be captured in separate chunks of that duration, rather than the default behavior of recording the media in a single large chunk.

MediaRecorder.stop()

Stops recording, at which point a dataavailable event containing the final Blob of saved data is fired. No more recording occurs.

Events

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

dataavailable

Fires periodically each time timeslice milliseconds of media have been recorded (or when the entire media has been recorded, if timeslice wasn't specified). The event, of type BlobEvent, contains the recorded media in its data property.

error

Fired when there are fatal errors that stop recording. The received event is based on the MediaRecorderErrorEvent interface, whose error property contains a DOMException that describes the actual error that occurred.

pause

Fired when media recording is paused.

resume

Fired when media recording resumes after being paused.

start

Fired when media recording starts.

stop

Fired when media recording ends, either when the MediaStream ends, or after the MediaRecorder.stop() method is called.

warning Deprecated

Fired when media recording has a non-fatal error.

Example

js

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

  const constraints = { audio: true };
  let chunks = [];

  navigator.mediaDevices
    .getUserMedia(constraints)
    .then((stream) => {
      const mediaRecorder = new MediaRecorder(stream);

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

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

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

        const clipName = prompt("Enter a name for your sound clip");

        const clipContainer = document.createElement("article");
        const clipLabel = document.createElement("p");
        const audio = document.createElement("audio");
        const deleteButton = document.createElement("button");

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

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

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

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

      mediaRecorder.ondataavailable = (e) => {
        chunks.push(e.data);
      };
    })
    .catch((err) => {
      console.error(`The following error occurred: ${err}`);
    });
}

Note: This code sample is inspired by the Web Dictaphone demo. Some lines have been omitted for brevity; refer to the source for the complete code.

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
MediaRecorder 47 79 25 No 36 14.1 47 47 25 36 14 5.0
MediaRecorder 47 79
25Before Firefox 58, using MediaStream.addTrack() on a stream obtained using getUserMedia(), then attempting to record the resulting stream would result in only recording the original stream without the added tracks (severe bug).
No 36 14.1 47 47
25Before Firefox 58, using MediaStream.addTrack() on a stream obtained using getUserMedia(), then attempting to record the resulting stream would result in only recording the original stream without the added tracks (severe bug).
36 14 5.0
audioBitrateMode 89 89 No No 75 No 89 89 No 63 No 15.0
audioBitsPerSecond 49 79 71 No 36 14.1 49 49 79 36 14.5 5.0
dataavailable_event 49 79 25 No 36 14.1 49 49 25 36 14 5.0
error_event
49The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
79The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
25 No
36The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
14.1
49The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
49The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
25
36The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
14
5.0The interface for this event is a plain Event, not MediaRecorderErrorEvent. See bug 1250432.
isTypeSupported_static 47 79 25 No 36 14.1 47 47 25 36 14 5.0
mimeType 49
47–49Before Chrome 49, only video is supported, not audio.
79
25Starting with Firefox 71, the behavior of mimeType is more consistent. For example, it now returns the media type even after recording has stopped.
No 36 14.1 49
47–49Before Chrome 49, only video is supported, not audio.
49
47–49Before Chrome 49, only video is supported, not audio.
25 36 14 5.0
pause 49 79 25 No 36 14.1 49 49 25 36 14.5 5.0
pause_event 49 79 65 No 36 14.1 49 49 65 36 14.5 5.0
requestData 49 79 25 No 36 14.1 49 49 25 36 14 5.0
resume 49 79 25 No 36 14.1 49 49 25 36 14.5 5.0
resume_event 49 79 65 No 36 14.1 49 49 65 36 14.5 5.0
start 47 79 25 No 36 14.1 47 47 25 36 14 5.0
start_event 49 79 25 No 36 14.1 49 49 25 36 14 5.0
state 49
47–49Before Chrome 49, only video is supported, not audio.
79 25 No 36 14.1 49
47–49Before Chrome 49, only video is supported, not audio.
49
47–49Before Chrome 49, only video is supported, not audio.
25 36 14 5.0
stop 49 79 25 No 36 14.1 49 49 25 36 14 5.0
stop_event 49 79 25 No 36 14.1 49 49 25 36 14 5.0
stream 49
47–49Before Chrome 49, only video is supported, not audio.
79 25 No 36 14.1 49 49
47–49Before Chrome 49, only video is supported, not audio.
25 36 14 5.0
videoBitsPerSecond 49 79 71 No 36 14.1 49 49 79 36 14.5 5.0
warning_event 49 79 25–71 No 36 No 49 49 25 36 No 5.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/MediaRecorder