With this instance of Recorder.js you can trigger the record method that starts to recording the received Audio and it will run indefinitely until the stop method from the same instance of recorder is triggered.

The Recorder.js class expects as first argument the handled stream as first argument namely the input. The previous variables should be stored globally or at least accesible in the scope for the rest of functions. This stream needs to be handled with the createMediaStreamSource method from an instance of the AudioContext API. All that you need to do is to request the microphone, once the user allows the access to the microphone, a stream object is received in the success callback of the initialization. With Recorder.js, the recording process is pretty simple. To record audio in the browser, you will need obviously access to the microphone with the getUserMedia API and the AudioContext API, so be sure that your browser supports these APIs. In this article we'll show you how to record the Audio received by the Microphone using the Recorder.js library in the browser. Obviously this process needs the approval of the user, which means that this feature can be really useful for systems like online language evalutions etc. The WebRTC advances by leaps and bounds. Using only the browser, you are able to record, although in not all of them, the Audio from the microphone of the visitor.

How to extract audio from video java