1 files changed, 31 insertions, 0 deletions
diff --git a/tools/spectral_editor/dct.js b/tools/spectral_editor/dct.js
new file mode 100644
index 0000000..e48ce2b
--- /dev/null
+++ b/tools/spectral_editor/dct.js
@@ -0,0 +1,31 @@
+const dctSize = 512; // Default DCT size, read from header
+
+// --- Utility Functions for Audio Processing ---
+// JavaScript equivalent of C++ idct_512
+function javascript_idct_512(input) {
+    const output = new Float32Array(dctSize);
+    const PI = Math.PI;
+    const N = dctSize;
+
+    for (let n = 0; n < N; ++n) {
+        let sum = input[0] / 2.0;
+        for (let k = 1; k < N; ++k) {
+            sum += input[k] * Math.cos((PI / N) * k * (n + 0.5));
+        }
+        output[n] = sum * (2.0 / N);
+    }
+    return output;
+}
+
+// Hanning window for smooth audio transitions (JavaScript equivalent)
+function hanningWindow(size) {
+    const window = new Float32Array(size);
+    const PI = Math.PI;
+    for (let i = 0; i < size; i++) {
+        window[i] = 0.5 * (1 - Math.cos((2 * PI * i) / (size - 1)));
+    }
+    return window;
+}
+
+const hanningWindowArray = hanningWindow(dctSize); // Pre-calculate window
+