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spectrum.html
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<!DOCTYPE html>
<body>
<script>
const audioCtx = new AudioContext();
//Create audio source
//Here, we use an audio file, but this could also be e.g. microphone input
const audioEle = new Audio();
audioEle.src = "2023-05-23-19-00-00.mp3"; //insert file name here
audioEle.autoplay = true;
audioEle.preload = "auto";
const audioSourceNode = audioCtx.createMediaElementSource(audioEle);
//Create analyser node
const analyserNode = audioCtx.createAnalyser();
analyserNode.fftSize = 256;
const bufferLength = analyserNode.frequencyBinCount;
const dataArray = new Float32Array(bufferLength);
//Set up audio node network
audioSourceNode.connect(analyserNode);
analyserNode.connect(audioCtx.destination);
//Create 2D canvas
const canvas = document.createElement("canvas");
canvas.style.position = "absolute";
canvas.style.top = "0";
canvas.style.left = "0";
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
document.body.appendChild(canvas);
const canvasCtx = canvas.getContext("2d");
canvasCtx.clearRect(0, 0, canvas.width, canvas.height);
console.log('ok', audioEle)
function draw() {
//Schedule next redraw
requestAnimationFrame(draw);
//Get spectrum data
analyserNode.getFloatFrequencyData(dataArray);
//Draw black background
canvasCtx.fillStyle = "rgb(0, 0, 0)";
canvasCtx.fillRect(0, 0, canvas.width, canvas.height);
//Draw spectrum
const barWidth = (canvas.width / bufferLength) * 2.5;
let posX = 0;
for (let i = 0; i < bufferLength; i++) {
const barHeight = (dataArray[i] + 140) * 2;
canvasCtx.fillStyle =
"rgb(" + Math.floor(barHeight + 100) + ", 50, 50)";
canvasCtx.fillRect(
posX,
canvas.height - barHeight / 2,
barWidth,
barHeight / 2
);
posX += barWidth + 1;
}
}
draw();
</script>
</body>