homeclaw/web-ui/voice-call-worklets.js

// AudioWorkletProcessors for the real-time voice call mode.
// Kept deliberately dumb: capture does downsampling + chunking + RMS only,
// playback does ring-buffer PCM output only. All turn-taking / VAD / WS
// logic lives in voice-call.js on the main thread.

class MicCaptureProcessor extends AudioWorkletProcessor {
  constructor() {
    super();
    this.targetRate = 16000;
    this.srcRate = sampleRate; // AudioWorkletGlobalScope — native context rate
    this.ratio = this.srcRate / this.targetRate;
    this.acc = 0;            // fractional resample accumulator
    this.chunk = [];         // pending int16 samples for the current outgoing chunk
    this.chunkSamples = Math.round(this.targetRate * 0.1); // ~100ms per chunk
  }

  process(inputs) {
    const input = inputs[0];
    if (!input || !input[0]) return true;
    const ch = input[0];

    for (let i = 0; i < ch.length; i++) {
      this.acc += 1;
      if (this.acc >= this.ratio) {
        this.acc -= this.ratio;
        const s = Math.max(-1, Math.min(1, ch[i]));
        this.chunk.push(s < 0 ? s * 0x8000 : s * 0x7fff);
        if (this.chunk.length >= this.chunkSamples) {
          const int16 = new Int16Array(this.chunk);
          let sumSq = 0;
          for (let j = 0; j < int16.length; j++) { const v = int16[j] / 32768; sumSq += v * v; }
          const rms = Math.sqrt(sumSq / int16.length);
          this.port.postMessage({ type: 'audio', pcm: int16, rms }, [int16.buffer]);
          this.chunk = [];
        }
      }
    }
    return true;
  }
}
registerProcessor('mic-capture-processor', MicCaptureProcessor);

class PcmPlayerProcessor extends AudioWorkletProcessor {
  constructor() {
    super();
    this.queue = [];   // array of Float32Array
    this.qi = 0;        // read offset within queue[0]
    this.port.onmessage = (e) => {
      const msg = e.data;
      if (msg.type === 'push') {
        const int16 = msg.pcm;
        const f32 = new Float32Array(int16.length);
        for (let i = 0; i < int16.length; i++) f32[i] = int16[i] / 32768;
        this.queue.push(f32);
      } else if (msg.type === 'clear') {
        this.queue = [];
        this.qi = 0;
      }
    };
  }

  process(_inputs, outputs) {
    const out = outputs[0][0];
    if (!out) return true;
    let oi = 0;
    while (oi < out.length) {
      if (this.queue.length === 0) {
        out[oi++] = 0;
        continue;
      }
      const cur = this.queue[0];
      out[oi++] = cur[this.qi++];
      if (this.qi >= cur.length) {
        this.queue.shift();
        this.qi = 0;
      }
    }
    return true;
  }
}
registerProcessor('pcm-player-processor', PcmPlayerProcessor);