server/lib/private/Preview/MP3.php

<?php
/**
 * @copyright Copyright (c) 2016, ownCloud, Inc.
 *
 * @author Georg Ehrke <oc.list@georgehrke.com>
 * @author Joas Schilling <coding@schilljs.com>
 * @author Lukas Reschke <lukas@statuscode.ch>
 * @author Olivier Paroz <github@oparoz.com>
 * @author Roeland Jago Douma <roeland@famdouma.nl>
 * @author Thomas Tanghus <thomas@tanghus.net>
 *
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
namespace OC\Preview;

use ID3Parser\ID3Parser;

use OCP\Files\File;
use OCP\IImage;

class MP3 extends ProviderV2 {
	/**
	 * {@inheritDoc}
	 */
	public function getMimeType(): string {
		return '/audio\/mpeg/';
	}

	/**
	 * {@inheritDoc}
	 */
	public function getThumbnail(File $file, int $maxX, int $maxY): ?IImage {
		$getID3 = new ID3Parser();

		$tmpPath = $this->getLocalFile($file);
		$tags = $getID3->analyze($tmpPath);
		$this->cleanTmpFiles();
		$picture = isset($tags['id3v2']['APIC'][0]['data']) ? $tags['id3v2']['APIC'][0]['data'] : null;
		if(is_null($picture) && isset($tags['id3v2']['PIC'][0]['data'])) {
			$picture = $tags['id3v2']['PIC'][0]['data'];
		}

		if(!is_null($picture)) {
			$image = new \OC_Image();
			$image->loadFromData($picture);

			if ($image->valid()) {
				$image->scaleDownToFit($maxX, $maxY);

				return $image;
			}
		}

		return null;
	}
}