Recording a screencast

In fact, while building the service for taking screenshots, we have done most of the work for screencast recording. We already have the MediaStream object delivered by webkitGetUserMedia. We just need a way to define the start and end of recording and save the collected frames in a video file. That is where we can benefit from the MediaStream Recording API, which captures the data produced by MedaStream or HTMLMediaElement (for example, <video>) so that we can save it. So, we modify the service again:

./js/Service/Capturer.js

//... 
const toBuffer = require( "blob-to-buffer" ); 
//... 
start( desktopStreamId ){ 
    navigator.webkitGetUserMedia(/* constaints */, ( stream ) => { 
        let chunks = []; 
        this.dom.video.srcObject = stream; 
        this.mediaRecorder = new MediaRecorder( stream ); 
        this.mediaRecorder.onstop = ( e ) => { 
          const blob = new Blob( chunks, { type: "video/webm" }); 
          toBuffer( blob, ( err, buffer...