Add @mediabunny/dts extension package

shared/dts-misc.ts

@@ -0,0 +1,33 @@
+/*!
+ * 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 the core can be encoded at (Table 5-5) */
+export const DTS_SAMPLE_RATES = [8000, 11025, 12000, 16000, 22050, 24000, 32000, 44100, 48000];
+
+/** Channel counts DTS has a speaker layout for; 3 and 7 have no mapping */
+export const DTS_CHANNEL_COUNTS = [1, 2, 4, 5, 6];
+
+const DTS_MAX_FRAME_SIZE = 16384;
+
+/**
+ * The DTS encoder needs each frame to be big enough to hold the per-channel side info and rejects the whole
+ * configuration when it isn't, so this mirrors the check from FFmpeg's dcaenc.c.
+ */
+export const dtsBitrateFits = (bitrate: number, sampleRate: number, numberOfChannels: number) => {
+	if (bitrate < 32000 || bitrate > 3840000) {
+		return false;
+	}
+
+	const hasLfe = numberOfChannels === 6;
+	const fullbandChannels = numberOfChannels - (hasLfe ? 1 : 0);
+
+	const frameBits = 32 * Math.ceil(Math.ceil(bitrate * 512 / sampleRate) / 32);
+	const minFrameBits = 132 + (493 + 28 * 32) * fullbandChannels + (hasLfe ? 72 : 0);
+
+	return frameBits >= minFrameBits && frameBits <= 8 * DTS_MAX_FRAME_SIZE;
+};