ytplayer/frontend/vendor/jamesdsp/jamesdsp-feature.js

/* Lazy classic-script bridge for the optional JamesDSP ES module and worklet. */
(function (root) {
  'use strict';

  const PRESETS = Object.freeze({
    flat: { name: 'Flat', params: {} },
    bass: { name: 'Bass', params: { 'eq.enabled': 1, 'eq.band0': 4, 'eq.band1': 3, 'bass.enabled': 1, 'bass.boost': 5, gain: -3 } },
    vocal: { name: 'Vocal', params: { 'eq.enabled': 1, 'eq.band5': 2, 'eq.band7': 3, 'eq.band9': 2, 'compressor.enabled': 1 } },
    loudness: { name: 'Loudness', params: { 'limiter.threshold': -3, gain: 2 } },
    headphone: { name: 'Headphone', params: { 'crossfeed.enabled': 1, 'crossfeed.mode': 1 } },
    bright: { name: 'Bright', params: { 'eq.enabled': 1, 'eq.band9': 2, 'eq.band10': 3, 'eq.band11': 3, 'eq.band12': 2 } },
    warm: { name: 'Warm', params: { 'eq.enabled': 1, 'eq.band0': 3, 'eq.band1': 2, 'eq.band7': -1, gain: -2 } },
  });

  const clampGain = value => Math.max(-24, Math.min(12, Number(value) || 0));

  function createController(options) {
    const graph = options.graph;
    let desired = false, active = false, nodeEntry = null, gainNode = null, context = null;
    let elements = [], standardInput = null, levelDb = 0, settings = null;
    let tail = Promise.resolve(), maxLiveHeaps = 0, liveHeaps = 0, nodesCreated = 0, nodesDestroyed = 0;
    let faultListener = null, notifying = false, dspAnalyser = null;

    const serial = fn => {
      const result = tail.then(fn, fn);
      tail = result.catch(() => {});
      return result;
    };

    function snapshot() { return { active, desired, liveHeaps, maxLiveHeaps, nodesCreated, nodesDestroyed, sampleRate: context?.sampleRate || null }; }

    function routeStandard() {
      if (!elements.length) return;
      try {
        graph.routeAll(elements, standardInput || context?.destination);
      } catch (error) {
        try { if (context?.destination) graph.routeAll(elements, context.destination); } catch { /* direct graph route is the last audible fallback */ }
        throw error;
      }
    }

    function releaseNode() {
      const entry = nodeEntry;
      nodeEntry = null;
      if (faultListener && entry) entry.node.removeEventListener('error', faultListener);
      faultListener = null;
      try { entry?.node.node.disconnect(); } catch { /* already disconnected */ }
      try { gainNode?.disconnect(); } catch { /* already disconnected */ }
      gainNode = null;
      try { dspAnalyser?.disconnect(); } catch { /* already disconnected */ }
      dspAnalyser = null;
      if (entry) {
        try { entry.node.destroy(); } catch { /* continue freeing references */ }
        if (entry.live) { entry.live = false; liveHeaps = Math.max(0, liveHeaps - 1); nodesDestroyed++; }
      }
    }

    function fail(error) {
      desired = false;
      active = false;
      try { routeStandard(); } catch { /* graph route has already tried a direct audible fallback */ }
      releaseNode();
      if (!notifying) {
        notifying = true;
        try { options.onError?.(error instanceof Error ? error : new Error(String(error || 'JamesDSP failed'))); }
        finally { notifying = false; }
      }
    }

    function rampGain(value) {
      if (!gainNode || !context) return;
      const param = gainNode.gain;
      const now = context.currentTime || 0;
      if (context.state !== 'running' || typeof param.linearRampToValueAtTime !== 'function') {
        param.value = value;
        return;
      }
      param.cancelScheduledValues?.(now);
      param.setValueAtTime?.(param.value, now);
      param.linearRampToValueAtTime(value, now + 0.018);
    }

    async function configure(instance, nextSettings, nextLevelDb) {
      const preset = PRESETS[nextSettings?.preset] || PRESETS.flat;
      const params = { ...preset.params, ...(nextSettings?.params || {}) };
      params.gain = clampGain((Number(params.gain) || 0) + (Number(nextLevelDb) || 0));
      params.bypass = 1;
      if (active && context?.state === 'running') {
        rampGain(0);
        await new Promise(resolve => setTimeout(resolve, 20));
      }
      await instance.setBypass(true);
      await instance.applyPreset(params);
      await instance.setParam('gain', params.gain);
      if (desired) await instance.setBypass(false);
      if (desired) rampGain(1);
    }

    async function loadNode(audioContext) {
      const moduleURL = root.Lazy.url('/vendor/jamesdsp/jamesdsp-node.mjs');
      const { JamesDSPNode } = await import(moduleURL);
      return JamesDSPNode.create(audioContext, {
        wasmURL: root.Lazy.url('/vendor/jamesdsp/dsp/jamesdsp.wasm'),
        engineURL: root.Lazy.url('/vendor/jamesdsp/dsp/jamesdsp.mjs'),
        paramsURL: root.Lazy.url('/vendor/jamesdsp/params.mjs'),
        workletURL: root.Lazy.url('/vendor/jamesdsp/worklet.mjs'),
      });
    }

    async function enable(nextSettings, nextLevelDb = levelDb) {
      desired = true;
      settings = nextSettings || {};
      levelDb = Number(nextLevelDb) || 0;
      return serial(async () => {
        if (!desired) return false;
        const prepared = await options.prepareGraph();
        context = prepared.context;
        elements = prepared.elements;
        standardInput = prepared.standardInput;
        if (![44100, 48000].includes(context?.sampleRate)) throw new RangeError(`JamesDSP supports 44.1 or 48 kHz; this device uses ${context?.sampleRate || 'unknown'} Hz`);
        if (!desired) return false;
        let instance = nodeEntry?.node;
        if (!instance) {
          instance = await (options.loadNode || loadNode)(context);
          if (!desired) { try { instance.destroy(); } catch {} return false; }
          nodeEntry = { node: instance, live: true };
          liveHeaps++; nodesCreated++; maxLiveHeaps = Math.max(maxLiveHeaps, liveHeaps);
          faultListener = event => fail(event.detail || new Error('JamesDSP processing failed'));
          instance.addEventListener('error', faultListener);
          gainNode = context.createGain();
          gainNode.gain.value = 1;
          instance.node.connect(gainNode);
          gainNode.connect(context.destination);
        }
        if (!desired) { releaseNode(); return false; }
        await configure(instance, settings, levelDb);
        if (!desired) { releaseNode(); return false; }
        if (context.state === 'suspended') await context.resume().catch(() => {});
        graph.routeAll(elements, instance.node);
        active = true;
        return true;
      }).catch(error => { fail(error); throw error; });
    }

    function disable() {
      desired = false;
      if (active) {
        active = false;
        try { routeStandard(); } catch { /* routeStandard tried its direct fallback */ }
      }
      return serial(async () => { releaseNode(); return true; });
    }

    function setLevelDb(value) {
      levelDb = Number(value) || 0;
      if (!desired) return Promise.resolve(false);
      return enable(settings, levelDb);
    }

    function setBypass(value) {
      if (!nodeEntry) return Promise.resolve(false);
      return nodeEntry.node.setBypass(Boolean(value));
    }

    function analyser() {
      if (!active || !gainNode || !context) return null;
      if (!dspAnalyser) {
        dspAnalyser = context.createAnalyser();
        dspAnalyser.fftSize = 128;
        dspAnalyser.smoothingTimeConstant = 0.78;
        gainNode.disconnect();
        gainNode.connect(dspAnalyser);
        dspAnalyser.connect(context.destination);
      }
      return dspAnalyser;
    }

    return { enable, disable, setLevelDb, setBypass, analyser, get active() { return active; }, get desired() { return desired; }, state: snapshot };
  }

  const api = { PRESETS, createController };
  if (typeof module !== 'undefined' && module.exports) module.exports = api;
  else {
    root.YT = root.YT || {};
    root.YT.JamesDSPFeature = api;
  }
})(typeof window !== 'undefined' ? window : globalThis);