feat: mic bpm

Author: sliterok

mic-sender.js

@@ -1,10 +1,45 @@
-import record from 'node-record-lpcm16'
+import { Essentia, arrayToVector } from 'essentia.js'
+import mic from 'mic'
 import WebSocket from 'ws'
 
-const url = process.argv[2] || 'ws://localhost:8081'
-const ws = new WebSocket(url)
+async function main() {
+  const url = process.argv[2] || 'ws://localhost:8081'
+  const ws = new WebSocket(url)
+  await new Promise(resolve => ws.once('open', resolve))
+
+  const essentia = await Essentia()
+  const sampleRate = 44100
+  const bufferSizeSec = 5
+  const bufferSize = sampleRate * bufferSizeSec
+  let buffer = new Float32Array(0)
+
+  const rhythmAlgo = (signal) =>
+    essentia.RhythmExtractor2013({ signal, sampleRate })
+
+  const micInst = mic({ rate: sampleRate.toString(), channels: '1' })
+  const micStream = micInst.getAudioStream()
+
+  micInst.start()
+
+  micStream.on('data', (chunk) => {
+    ws.send(chunk)
+    const pcm = new Float32Array(chunk.buffer, chunk.byteOffset, chunk.length / 4)
+    const tmp = new Float32Array(buffer.length + pcm.length)
+    tmp.set(buffer)
+    tmp.set(pcm, buffer.length)
+    buffer = tmp
+    if (buffer.length >= bufferSize) {
+      const sigVec = arrayToVector(buffer)
+      const res = rhythmAlgo(sigVec)
+      const bpm = res.bpm
+      ws.send(JSON.stringify({ bpm }))
+      console.log(`BPM: ${bpm.toFixed(2)}, ticks: ${res.ticks.length}`)
+      buffer = buffer.subarray(bufferSize)
+    }
+  })
+
+  micStream.on('error', console.error)
+}
+
+main().catch(console.error)
 
-ws.on('open', () => {
-  const mic = record.start({ sampleRate: 44100, channels: 1 })
-  mic.on('data', chunk => ws.send(chunk))
-})

package.json

@@ -54,7 +54,8 @@
 		"express": "^4.18.2",
 		"fft-js": "^0.0.12",
 		"music-tempo": "^1.0.3",
-		"node-record-lpcm16": "^1.0.1",
+                "mic": "^2.1.1",
+                "essentia.js": "^0.1.3",
 		"react": "^19.1.0",
 		"react-colorful": "^5.6.1",
 		"react-dom": "^19.1.0",

pnpm-lock.yaml

@@ -55,15 +55,17 @@ export const getPulseColor: IColorGetter = (_, time) => {
 
 	const dt = (time - lastPulseTime) * settings.effectSpeed
 	lastPulseTime = time
-	pulsePhase += dt / pulseCycle
+
+	const elapsed = pulsePhase * pulseCycle + dt
+	pulseCycle = target
+	pulsePhase = elapsed / pulseCycle
 
 	if (pulsePhase >= 1) {
-		pulsePhase %= 1
+		const cycles = Math.floor(pulsePhase)
+		pulsePhase -= cycles
 		pulseColor = hslToRgb(Math.random() * 360, 1, 0.5)
 	}
 
-	pulseCycle = target
-
 	const intensity = Math.sin(pulsePhase * Math.PI)
 	return pulseColor.map(c => Math.round(c * intensity)) as IArrColor
 }

src/backend/pattern/extra.ts

@@ -20,7 +20,16 @@ export function startAudioServer(port = 8081) {
 	const wss = new WebSocketServer({ port })
 	wss.on('connection', ws => {
 		ws.on('message', data => {
-			if (Buffer.isBuffer(data)) processAudio(data)
+			if (Buffer.isBuffer(data)) {
+				processAudio(data)
+			} else {
+				try {
+					const msg = JSON.parse(data.toString())
+					if (typeof msg.bpm === 'number') audioState.bpm = msg.bpm
+				} catch {
+					// ignore non-json messages
+				}
+			}
 		})
 	})
 }