feat: build reproducible dataset editor

packages/acoustics-core/index.js

@@ -2,7 +2,9 @@ export * from "./das.js";
 export * from "./fft.js";
 export * from "./fractional-delay.js";
 export * from "./math.js";
+export * from "./mixdown.js";
 export * from "./noise.js";
 export * from "./propagation.js";
 export * from "./signal.js";
 export * from "./stft.js";
+export * from "./wav.js";

packages/acoustics-core/mixdown.js

@@ -0,0 +1,64 @@
+import { renderSignal } from "./signal.js";
+
+export const MAX_MIX_WORKING_BYTES = 384 * 1024 * 1024;
+export const MAX_MIX_SAMPLE_OPERATIONS = 250_000_000;
+
+export function estimateSceneMix(scene, assetBuffers = new Map()) {
+  const sampleCount = Math.ceil(scene.duration * scene.sampleRate);
+  const entryCount = scene.sources.length + (scene.ambient?.length ?? 0);
+  let assetBytes = 0;
+  for (const asset of assetBuffers.values()) {
+    for (const channel of asset.channels ?? []) assetBytes += channel.byteLength ?? 0;
+  }
+  return {
+    sampleCount,
+    entryCount,
+    assetBytes,
+    workingBytes: sampleCount * Float32Array.BYTES_PER_ELEMENT * 2 + assetBytes,
+    sampleOperations: sampleCount * entryCount,
+  };
+}
+
+export function renderSceneMix(scene, assetBuffers = new Map()) {
+  const estimate = estimateSceneMix(scene, assetBuffers);
+  if (!Number.isSafeInteger(estimate.sampleCount) || estimate.sampleCount <= 0) {
+    throw new Error("장면 sample 수가 올바르지 않습니다.");
+  }
+  if (estimate.workingBytes > MAX_MIX_WORKING_BYTES) {
+    throw new Error(
+      `확인용 mix 작업 메모리 ${(estimate.workingBytes / 1024 ** 2).toFixed(1)} MiB가 ` +
+        `${(MAX_MIX_WORKING_BYTES / 1024 ** 2).toFixed(0)} MiB 한도를 넘습니다. duration 또는 sample rate를 줄이세요.`,
+    );
+  }
+  if (estimate.sampleOperations > MAX_MIX_SAMPLE_OPERATIONS) {
+    throw new Error(
+      `확인용 mix 연산량 ${estimate.sampleOperations.toLocaleString()} samples가 ` +
+        `${MAX_MIX_SAMPLE_OPERATIONS.toLocaleString()} 한도를 넘습니다. duration 또는 음원 수를 줄이세요.`,
+    );
+  }
+  const { sampleCount } = estimate;
+  const samples = new Float32Array(sampleCount);
+  for (const source of scene.sources) {
+    const sourceSamples = renderSignal(source, scene, assetBuffers);
+    for (let index = 0; index < sampleCount; index += 1) samples[index] += sourceSamples[index];
+  }
+  for (const ambient of scene.ambient ?? []) {
+    const ambientSamples = renderSignal(ambient, scene, assetBuffers);
+    for (let index = 0; index < sampleCount; index += 1) samples[index] += ambientSamples[index];
+  }
+
+  let preNormalizationPeak = 0;
+  for (const value of samples) preNormalizationPeak = Math.max(preNormalizationPeak, Math.abs(value));
+  const appliedScale =
+    scene.mix?.normalization === "peak" && preNormalizationPeak > 0
+      ? scene.mix.targetPeak / preNormalizationPeak
+      : 1;
+  let peak = 0;
+  let clippedSampleCount = 0;
+  for (let index = 0; index < samples.length; index += 1) {
+    samples[index] *= appliedScale;
+    peak = Math.max(peak, Math.abs(samples[index]));
+    if (Math.abs(samples[index]) > 1) clippedSampleCount += 1;
+  }
+  return { samples, sampleRate: scene.sampleRate, preNormalizationPeak, appliedScale, peak, clippedSampleCount };
+}

packages/acoustics-core/wav.js

@@ -0,0 +1,43 @@
+function writeAscii(view, offset, value) {
+  for (let index = 0; index < value.length; index += 1) view.setUint8(offset + index, value.charCodeAt(index));
+}
+
+export const MAX_PCM_WAV_BYTES = 384 * 1024 * 1024;
+
+export function encodeMonoPcm16Wav(samples, sampleRate) {
+  if (!Number.isInteger(sampleRate) || sampleRate < 1 || sampleRate > 0xffffffff) {
+    throw new Error(`WAV sample rate가 올바르지 않습니다: ${sampleRate}`);
+  }
+  if (!samples || !Number.isSafeInteger(samples.length)) {
+    throw new Error("WAV samples는 길이가 있는 배열이어야 합니다.");
+  }
+  const bytesPerSample = 2;
+  const dataByteLength = samples.length * bytesPerSample;
+  if (!Number.isSafeInteger(dataByteLength) || dataByteLength > 0xffffffff - 36) {
+    throw new Error("PCM16 WAV가 RIFF 4 GiB 한도를 넘습니다.");
+  }
+  if (44 + dataByteLength > MAX_PCM_WAV_BYTES) {
+    throw new Error(`PCM16 WAV가 ${(MAX_PCM_WAV_BYTES / 1024 ** 2).toFixed(0)} MiB 메모리 한도를 넘습니다.`);
+  }
+  const buffer = new ArrayBuffer(44 + dataByteLength);
+  const view = new DataView(buffer);
+  writeAscii(view, 0, "RIFF");
+  view.setUint32(4, 36 + dataByteLength, true);
+  writeAscii(view, 8, "WAVE");
+  writeAscii(view, 12, "fmt ");
+  view.setUint32(16, 16, true);
+  view.setUint16(20, 1, true);
+  view.setUint16(22, 1, true);
+  view.setUint32(24, sampleRate, true);
+  view.setUint32(28, sampleRate * bytesPerSample, true);
+  view.setUint16(32, bytesPerSample, true);
+  view.setUint16(34, 16, true);
+  writeAscii(view, 36, "data");
+  view.setUint32(40, dataByteLength, true);
+  for (let index = 0; index < samples.length; index += 1) {
+    if (!Number.isFinite(samples[index])) throw new Error(`WAV sample ${index}가 유한한 숫자가 아닙니다.`);
+    const value = Math.max(-1, Math.min(1, samples[index]));
+    view.setInt16(44 + index * 2, value < 0 ? value * 0x8000 : value * 0x7fff, true);
+  }
+  return new Blob([buffer], { type: "audio/wav" });
+}