interactive-player/dist/interactive-player.js

A front-end interactive music audio player using AudioWorklet for javascript and typescript

// src/interactive-player.ts
var InteractivePlayer = class {
  constructor() {
    this.ctx = new AudioContext();
    // 遅延初期化
    this.graph = {};
    const moduleUrl = (
      // ESM (ブラウザ / Node ESM)
      typeof import.meta !== "undefined" && import.meta.url || `file://${__dirname}/`
    );
    const workletUrl = new URL(
      "interactive-player-processor.js",
      moduleUrl
    );
    this.workletReady = this.ctx.audioWorklet.addModule(workletUrl.toString()).then(() => {
      this.node = new AudioWorkletNode(
        this.ctx,
        "interactive-player-processor"
      );
      this.node.connect(this.ctx.destination);
    });
  }
  /** 複数トラックをまとめてロード */
  async loadAll(tracks) {
    this.graph = tracks.reduce(
      (g, t, i) => (g[i] = t.next ?? null, g),
      {}
    );
    const buffers = await Promise.all(
      tracks.map(async (t) => {
        const arr = typeof t.src === "string" ? await (await fetch(t.src)).arrayBuffer() : t.src;
        return this.ctx.decodeAudioData(arr);
      })
    );
    await this.workletReady;
    const transferables = [];
    const payload = buffers.map((buf) => {
      const chans = [];
      for (let ch = 0; ch < buf.numberOfChannels; ch++) {
        const copy = new Float32Array(buf.getChannelData(ch));
        chans.push(copy.buffer);
        transferables.push(copy.buffer);
      }
      return chans;
    });
    this.node.port.postMessage(
      { type: "loadMulti", tracks: payload, transitions: this.graph },
      transferables
    );
  }
  /** 再生 */
  async play(startIdx = 0) {
    if (this.ctx.state !== "running") await this.ctx.resume();
    await this.workletReady;
    this.node.port.postMessage({ type: "play", start: startIdx });
  }
  /** 停止（頭出し） */
  async stop() {
    await this.workletReady;
    this.node.port.postMessage({ type: "stop" });
  }
  /** ポーズ／レジューム */
  async pause(isPause) {
    await this.workletReady;
    this.node.port.postMessage({ type: isPause ? "pause" : "resume" });
  }
  /** 次トラックをキューイング */
  async next(idx, currentIs = null) {
    await this.workletReady;
    this.node.port.postMessage({ type: "next", next: idx, currentIs });
  }
  async setFadeInSec(sec) {
    await this.workletReady;
    this.node.port.postMessage({
      type: "setFadeIn",
      fadeInSamples: this.secToSamples(sec)
    });
  }
  async setFadeOutSec(sec) {
    await this.workletReady;
    this.node.port.postMessage({
      type: "setFadeOut",
      fadeOutSamples: this.secToSamples(sec)
    });
  }
  secToSamples(sec) {
    return Math.floor(sec * this.ctx.sampleRate);
  }
};
export {
  InteractivePlayer as default
};
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