The MediaRecorder.requestData()
method (part of the MediaRecorder API) is used to raise a dataavailable
event containing a Blob
object of the captured media as it was when the method was called. This can then be grabbed and manipulated as you wish.
When the requestData()
method is invoked, the browser queues a task that runs the following steps:
- If
MediaRecorder.state
is not "recording", raise a DOMInvalidState
error and terminate these steps. IfMediaRecorder.state
is "recording", continue to the next step. - Raise a
dataavailable
event containing aBlob
of the currently captured data (the Blob is available under the event'sdata
attribute.) - Create a new Blob and place subsequently captured data into it.
Syntax
MediaRecorder.requestData()
Errors
An InvalidState
error is raised if the requestData()
method is called while the MediaRecorder
object’s MediaRecorder.state
is not "recording" — the media cannot be captured if recording is not occurring.
Example
... captureMedia.onclick = function() { mediaRecorder.requestData(); // makes snapshot available of data so far // ondataavailable fires, then capturing continues // in new Blob } ...
Specifications
Specification | Status | Comment |
---|---|---|
MediaStream Recording The definition of 'MediaRecorder.requestData()' in that specification. |
Working Draft | Initial definition |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 47[2] | 25.0 (25.0) | No support | No support | No support |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|---|
Basic support | No support | No support | 25.0 (25.0) | 1.3[1] | No support | No support | No support | No support |
[1] The intial Firefox OS implementation only supported audio recording.
[2] To try this feature on Chrome, enable Experimental Web Platform features from chrome://flags . Currently only video is supported, not audio.
See also
- Using the MediaRecorder API
- Web Dictaphone: MediaRecorder + getUserMedia + Web Audio API visualization demo, by Chris Mills (source on Github.)
- simpl.info MediaStream Recording demo, by Sam Dutton.
Navigator.getUserMedia