cinny/src/app/utils/denoisePipeline.ts

/**
 * Shared client-side denoise pipeline for the in-app model tester.
 *
 * The same RNNoise/Speex/DTLN worklets that the Element Call shim
 * (build/lotus-denoise.js) injects are shipped under
 * /public/element-call/denoise/. Here we load them into a normal main-app
 * AudioContext so users can audition the models and calibrate the noise gate
 * without joining a real call. The graph mirrors the shim:
 *   source -> [noise gate] -> model -> output
 */
import { DenoiseModelId } from '../state/settings';

// Mirror CallEmbed's widget-base resolution so assets resolve under any base.
const BASE = `${import.meta.env.BASE_URL.replace(/\/+$/, '')}/public/element-call/denoise/`;

/**
 * Required AudioContext sample rate per model. RNNoise/Speex (sapphi) and
 * DeepFilterNet 3 are 48 kHz. DTLN (@workadventure) targets 16 kHz and does NOT
 * resample internally — running it at 48 kHz produces robotic/choppy/quiet
 * output, so its whole graph must run in a 16 kHz context.
 */
export const sampleRateFor = (model: DenoiseModelId): number => (model === 'dtln' ? 16000 : 48000);

export type DenoiseNode = {
  node: AudioWorkletNode;
  dispose: () => void;
};

const wasmCache: Record<string, Promise<ArrayBuffer>> = {};
function fetchWasm(file: string): Promise<ArrayBuffer> {
  if (!wasmCache[file]) {
    wasmCache[file] = fetch(BASE + file).then((r) => {
      if (!r.ok) throw new Error(`denoise asset ${file} unavailable (${r.status})`);
      return r.arrayBuffer();
    });
  }
  return wasmCache[file];
}

// addModule throws if the same module URL is added twice to one context.
const addedModules = new WeakMap<BaseAudioContext, Set<string>>();
async function addModuleOnce(ctx: BaseAudioContext, script: string): Promise<void> {
  let set = addedModules.get(ctx);
  if (!set) {
    set = new Set();
    addedModules.set(ctx, set);
  }
  if (set.has(script)) return;
  await ctx.audioWorklet.addModule(BASE + script);
  set.add(script);
}

const SAPPHI: Record<'rnnoise' | 'speex', { proc: string; script: string; wasm: string }> = {
  rnnoise: {
    proc: '@sapphi-red/web-noise-suppressor/rnnoise',
    script: 'rnnoiseWorklet.js',
    wasm: 'rnnoise.wasm',
  },
  speex: {
    proc: '@sapphi-red/web-noise-suppressor/speex',
    script: 'speexWorklet.js',
    wasm: 'speex.wasm',
  },
};

/** Build the model denoise node. RNNoise/Speex are flat sapphi worklets; DTLN
 *  uses @workadventure's self-resolving ES-module helper. */
export async function buildModelNode(
  ctx: BaseAudioContext,
  model: DenoiseModelId,
): Promise<DenoiseNode> {
  if (model === 'dtln') {
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const mod: any = await import(/* @vite-ignore */ `${BASE}workadventure/audio-worklet.js`);
    const handle = await mod.createNoiseSuppressionAudioWorklet(ctx, { bypassUntilReady: true });
    return { node: handle.node, dispose: () => handle.dispose() };
  }
  if (model === 'deepfilternet') {
    // deepfilternet3-noise-filter ESM: inlines its worklet/wasm-bindgen glue and
    // fetches only df_bg.wasm + the ONNX model, which we self-host under
    // deepfilternet/v2/... Override its cdnUrl to our absolute base so nothing
    // hits the upstream CDN. DeepFilterNet3Core builds the worklet node directly.
    const dfnBase = new URL(`${BASE}deepfilternet`, window.location.href).href;
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    const mod: any = await import(/* @vite-ignore */ `${BASE}deepfilternet/index.esm.js`);
    const core = new mod.DeepFilterNet3Core({
      sampleRate: sampleRateFor(model),
      noiseReductionLevel: 80,
      assetConfig: { cdnUrl: dfnBase },
    });
    await core.initialize();
    const node: AudioWorkletNode = await core.createAudioWorkletNode(ctx);
    return {
      node,
      dispose: () => {
        try {
          core.destroy();
        } catch {
          /* noop */
        }
      },
    };
  }
  const cfg = SAPPHI[model];
  const [, wasmBinary] = await Promise.all([addModuleOnce(ctx, cfg.script), fetchWasm(cfg.wasm)]);
  const node = new AudioWorkletNode(ctx, cfg.proc, {
    channelCount: 1,
    numberOfInputs: 1,
    numberOfOutputs: 1,
    processorOptions: { maxChannels: 1, wasmBinary },
  });
  return {
    node,
    dispose: () => {
      try {
        node.port.postMessage('destroy');
      } catch {
        /* noop */
      }
    },
  };
}

export async function buildGateNode(
  ctx: BaseAudioContext,
  thresholdDb: number,
): Promise<AudioWorkletNode> {
  await addModuleOnce(ctx, 'noiseGateWorklet.js');
  return new AudioWorkletNode(ctx, '@sapphi-red/web-noise-suppressor/noise-gate', {
    processorOptions: {
      openThreshold: thresholdDb,
      closeThreshold: thresholdDb - 5,
      holdMs: 150,
      maxChannels: 1,
    },
  });
}

/** RMS level of an analyser as dBFS, clamped to [-100, 0]. */
export function readDb(analyser: AnalyserNode): number {
  const buf = new Float32Array(analyser.fftSize);
  analyser.getFloatTimeDomainData(buf);
  let sum = 0;
  for (let i = 0; i < buf.length; i += 1) sum += buf[i] * buf[i];
  const rms = Math.sqrt(sum / buf.length);
  return rms > 0 ? Math.max(-100, 20 * Math.log10(rms)) : -100;
}