Messing around with AudioContext and Canvas. Simple example, drop a music file on the canvas and watch.
Created
March 11, 2016 20:42
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Simple Audio Visualization
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| <canvas id="canvas" ></canvas> | |
| <canvas id="canvas2" ></canvas> | |
| <div id="note">Drag and Drop a Music File</div> |
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| // audio and analyser loading from http://codepen.io/agorkem/pen/qdazPG | |
| var audio, | |
| analyser, | |
| audioContext, | |
| sourceNode, | |
| stream, | |
| row = 0, | |
| next = 0, | |
| canvas = document.getElementById('canvas'), | |
| canvas2 = document.getElementById('canvas2'), | |
| note = document.getElementById('note'), | |
| context = canvas.getContext('2d'), | |
| context2 = canvas2.getContext('2d'), | |
| width = canvas.width = canvas2.width = window.innerWidth, | |
| height = canvas2.height = canvas.height = window.innerHeight, | |
| c = 0; | |
| audioContext = new AudioContext(); | |
| analyser = (analyser || audioContext.createAnalyser()); | |
| analyser.smoothingTimeConstant = 1; | |
| analyser.fftSize = 512; | |
| window.addEventListener('drop', function(e) { | |
| e.stopPropagation(); | |
| e.preventDefault(); | |
| stream = URL.createObjectURL(event.dataTransfer.files[0]); | |
| if (audio) | |
| audio.pause(); | |
| audio = new Audio(); | |
| audio.crossOrigin = "anonymous" | |
| audio.src = stream; | |
| start(); | |
| note.style.display = 'none'; | |
| }); | |
| window.addEventListener('dragover', function(e) { | |
| e.stopPropagation(); | |
| e.preventDefault(); | |
| }); | |
| function start() { | |
| audio.addEventListener('canplay', function() { | |
| sourceNode = audioContext.createMediaElementSource(audio); | |
| sourceNode.connect(analyser); | |
| sourceNode.connect(audioContext.destination); | |
| audio.play(); | |
| }); | |
| } | |
| update(); | |
| function update() { | |
| var freqArray = new Uint8Array(analyser.frequencyBinCount); | |
| analyser.getByteTimeDomainData(freqArray); | |
| context2.clearRect(0, 0, width, height); | |
| context2.lineWidth = 10; | |
| context2.beginPath(); | |
| for (var i = 0; i < freqArray.length; i += 10) { //skipping 10 to save your computers life | |
| var v = freqArray[i]; | |
| context2.strokeStyle = 'rgb(' + v + ', ' + v + ',' + v + ')' | |
| context.fillStyle = 'rgb(0, ' + v + ',' + v / 1.5 + ')' | |
| context2.lineTo(i * (width / freqArray.length), (height / 2) + (v - 128)); | |
| context2.stroke(); | |
| context.beginPath(); | |
| context.arc((width / 2), (height / 2), v * 1.5, 0, Math.PI * 2, true) | |
| context.fill(); | |
| // | |
| //} | |
| } | |
| requestAnimationFrame(update); | |
| } |
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| body,html{margin:0;padding:0;border:0;width:100%;height:100%} | |
| canvas{position:absolute;} | |
| div{ color:white;background-color:silver;padding: 5px 15px;border-radius: 15px; font: 400 25px 'Open Sans', sans-serif;text-align:center;} | |
| body{ | |
| background-color: #000000; | |
| margin: 0px; | |
| overflow: hidden; | |
| background-image: radial-gradient(ellipse farthest-corner at center, #23233f 0%, #000000 80%); | |
| } |
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