Add @mediabunny/ac3 extension package

packages/ac3/src/decoder.ts

@@ -0,0 +1,70 @@
+/*!
+ * 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/.
+ */
+
+import {
+	CustomAudioDecoder,
+	AudioCodec,
+	AudioSample,
+	EncodedPacket,
+	registerDecoder,
+} from 'mediabunny';
+import { sendCommand } from './worker-client';
+
+class Ac3Decoder extends CustomAudioDecoder {
+	private ctx = 0;
+
+	static override supports(codec: AudioCodec): boolean {
+		return codec === 'ac3' || codec === 'eac3';
+	}
+
+	async init() {
+		const result = await sendCommand({
+			type: 'init-decoder',
+			data: { codec: this.codec },
+		});
+		this.ctx = result.ctx;
+	}
+
+	async decode(packet: EncodedPacket) {
+		const encodedData = packet.data.slice().buffer;
+		const timestamp = Math.round(packet.timestamp * this.config.sampleRate);
+
+		const result = await sendCommand({
+			type: 'decode',
+			data: { ctx: this.ctx, encodedData, timestamp },
+		}, [encodedData]);
+
+		const sample = new AudioSample({
+			data: result.pcmData,
+			format: result.format,
+			numberOfChannels: result.channels,
+			sampleRate: result.sampleRate,
+			timestamp: result.pts / result.sampleRate,
+		});
+		this.onSample(sample);
+	}
+
+	async flush() {
+		await sendCommand({ type: 'flush-decoder', data: { ctx: this.ctx } });
+	}
+
+	close() {
+		void sendCommand({ type: 'close-decoder', data: { ctx: this.ctx } });
+	}
+}
+
+/**
+ * Registers AC-3 and E-AC-3 decoders, which Mediabunny will then use automatically when applicable. Make sure to call
+ * this function before starting any decoding task.
+ *
+ * @group \@mediabunny/ac3
+ * @public
+ */
+export const registerAc3Decoder = () => {
+	registerDecoder(Ac3Decoder);
+};