getid3_ac3::channelsEnabledLookup

	 *
	 * @return array
	 */
	public static function channelsEnabledLookup($acmod, $lfeon) {
		$lookup = array(
			'ch1'=>($acmod == 0),
			'ch2'=>($acmod == 0),
			'left'=>($acmod > 1),
			'right'=>($acmod > 1),
			'center'=>(bool) ($acmod & 0x01),
			'surround_mono'=>false,
			'surround_left'=>false,
			'surround_right'=>false,
			'lfe'=>$lfeon);
		switch ($acmod) {
			case 4:
			case 5:
				$lookup['surround_mono']  = true;
				break;
			case 6:
			case 7:
				$lookup['surround_left']  = true;
				$lookup['surround_right'] = true;
				break;