Initial Commit

packages/media/audio/audio-analysis-spectrum/tests/fixtures.ts

@@ -0,0 +1,51 @@
+import { AudioDocument } from "@suaveplan/audio-core/document/document";
+
+const PAGE_SIZE = 1024 * 1024;
+
+/** Build an `AudioDocument` from a flat mono `Float32Array`. */
+export function makeDoc(
+    samples: Float32Array,
+    sampleRate = 48_000
+): AudioDocument {
+    const pages: { channelData: Float32Array[]; startSample: number }[] = [];
+    let offset = 0;
+    while (offset < samples.length) {
+        const end = Math.min(offset + PAGE_SIZE, samples.length);
+        pages.push({
+            channelData: [samples.slice(offset, end)],
+            startSample: offset,
+        });
+        offset = end;
+    }
+    if (pages.length === 0) {
+        pages.push({ channelData: [new Float32Array(0)], startSample: 0 });
+    }
+    return new AudioDocument({
+        sampleRate,
+        channels: 1,
+        sourceLength: samples.length,
+        pages,
+    });
+}
+
+export function sineWave(
+    durationSec: number,
+    freqHz: number,
+    sampleRate = 48_000
+): Float32Array {
+    const n = Math.floor(durationSec * sampleRate);
+    const out = new Float32Array(n);
+    for (let i = 0; i < n; i++)
+        out[i] = Math.sin((2 * Math.PI * freqHz * i) / sampleRate);
+    return out;
+}
+
+export function whiteNoise(length: number, seed = 12345): Float32Array {
+    let s = seed >>> 0;
+    const out = new Float32Array(length);
+    for (let i = 0; i < length; i++) {
+        s = (1_664_525 * s + 1_013_904_223) >>> 0;
+        out[i] = (s / 0xffff_ffff) * 2 - 1;
+    }
+    return out;
+}