mediabunny/src/isobmff/isobmff-misc.ts

Pure TypeScript media toolkit for reading, writing, and converting media files, directly in the browser.

/*!
 * Copyright (c) 2025-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/.
 */

export const buildIsobmffMimeType = (info: {
	isQuickTime: boolean;
	hasVideo: boolean;
	hasAudio: boolean;
	codecStrings: string[];
}) => {
	const base = info.hasVideo
		? 'video/'
		: info.hasAudio
			? 'audio/'
			: 'application/';

	let string = base + (info.isQuickTime ? 'quicktime' : 'mp4');

	if (info.codecStrings.length > 0) {
		const uniqueCodecMimeTypes = [...new Set(info.codecStrings)];
		string += `; codecs="${uniqueCodecMimeTypes.join(', ')}"`;
	}

	return string;
};