Add @mediabunny/ac3 extension package

shared/ac3-misc.ts

@@ -0,0 +1,13 @@
+/*!
+ * Copyright (c) 2026-present, Vanilagy and contributors
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+/** Sample rates indexed by fscod (Table 4.1) */
+export const AC3_SAMPLE_RATES = [48000, 44100, 32000];
+
+/** E-AC-3 reduced sample rates for fscod2 per ATSC A/52:2018 */
+export const EAC3_REDUCED_SAMPLE_RATES = [24000, 22050, 16000];