getid3_ac3::surroundMixLevelLookup

	 *
	 * @return int|float|string|false
	 */
	public static function surroundMixLevelLookup($surmixlev) {
		static $surroundMixLevelLookup;
		if (empty($surroundMixLevelLookup)) {
			$surroundMixLevelLookup = array(
				0 => pow(2, -3.0 / 6),
				1 => pow(2, -6.0 / 6),
				2 => 0,
				3 => 'reserved'
			);