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<!DOCTYPE html>
<input type="text" id="text">
<button id="send">do thing</button>
<button id="recv">do thing 2</button>
<canvas id="vis" style="width: 100%; height: 20em; "></canvas>
<script>
const ctx = new AudioContext()
const encoder = new TextEncoder()
const visCanvas = document.querySelector("#vis")
const transmit = bytes => {
const tones = Array.from(bytes).flatMap(x => [x >> 6, x >> 4 & 3, x >> 2 & 3, x & 3])
console.log(tones)
let pos = 0
const oscillator = ctx.createOscillator()
oscillator.connect(ctx.destination)
oscillator.start()
const interval = setInterval(() => {
const tone = tones[pos]
oscillator.frequency.value = [200, 400, 600, 800][tone]
pos++
if (pos == tones.length) {
oscillator.stop()
oscillator.disconnect()
clearInterval(interval)
}
}, 500)
}
const analyzer = ctx.createAnalyser()
//analyzer.smoothingTimeConstant = 0
const CWIDTH = 512
const CWIDTH_MINUS_ONE = 511
const cctx = visCanvas.getContext("2d")
let q = 0;
const visualizerLoop = () => {
const w = analyzer.frequencyBinCount
const frequencyData = new Uint8Array(w)
analyzer.getByteFrequencyData(frequencyData)
const im = cctx.getImageData(1, 0, CWIDTH, w)
let max = -1;
let maxIndex = -1;
for (let i = 0; i < w; i++) {
im.data[(i * CWIDTH + CWIDTH_MINUS_ONE) * 4 + 3] = 255
im.data[(i * CWIDTH + CWIDTH_MINUS_ONE) * 4 + 1] = frequencyData[i]
if (frequencyData[i] > max) {
max = frequencyData[i]
maxIndex = i
}
}
console.log((maxIndex + 1) / w * 24000)
cctx.putImageData(im, 0, 0)
q++
requestAnimationFrame(visualizerLoop)
}
document.querySelector("#send").addEventListener("click", () => {
transmit(encoder.encode(document.querySelector("#text").value))
})
document.querySelector("#recv").addEventListener("click", () => {
navigator.mediaDevices.getUserMedia({video: false, audio: true}).then(stream => {
console.log(stream)
const node = ctx.createMediaStreamSource(stream)
node.connect(analyzer)
visCanvas.height = analyzer.frequencyBinCount
visCanvas.width = CWIDTH
cctx.fillStyle = "black"
cctx.fillRect(0, 0, CWIDTH, analyzer.frequencyBinCount)
requestAnimationFrame(visualizerLoop)
})
})
</script>