realTimeVideoRecorder = function(canvas) { var div = html`

` $('').text('RT Video Rec').appendTo(div); var startButton = $('').appendTo(div).css({margin:"0 14px"}).click(onStart); var stopButton = $('').appendTo(div).css({margin:"0 14px"}).hide().click(onStop); var progress = $('progress...').appendTo(div).hide(); var link = $('').appendTo(div).hide(); var recordedChunks = []; var mediaRecorder; var t0; var progressInterval=-1; const now = ()=> new Date().getTime(); function onStart(){ startButton.hide(); stopButton.show(); progress.show(); link.hide(); recordedChunks=[]; var fps = 25; var stream = canvas.captureStream(fps); mediaRecorder = new MediaRecorder(stream, { mimeType: "video/webm; codecs=vp9" }); mediaRecorder.start(); mediaRecorder.ondataavailable = function (event) { //console.log({ondataavailable:event.data}); recordedChunks.push(event.data); }; mediaRecorder.onstop = function (event) { //console.log({onstop:recordedChunks.length}); var blob = new Blob(recordedChunks, { type: "video/webm" }); var url = URL.createObjectURL(blob); link.text("download video").attr('href', url); }; t0=now(); progressInterval = setInterval(function(){ console.log('prog intv'); var t=((now()-t0)/1000).toFixed(1); progress.text("time: "+t+" sec"); }, 250); } function onStop(){ startButton.show(); stopButton.hide(); progress.hide(); link.show(); mediaRecorder.stop(); clearInterval(progressInterval); } return div; }