Wordpress: Add/Remove MineType

gistfile1.txt

//Add mineType
add_filter('upload_mimes','add_custom_mime_types');
	function add_custom_mime_types($mimes){
		return array_merge($mimes,array (
			'ac3' => 'audio/ac3',
			'mpa' => 'audio/MPA',
			'flv' => 'video/x-flv'
		));
}

//Remove mineType
add_filter('upload_mimes','remove_mime_types');
	function remove_mime_types($mimes){
		unset( $existing_mimes['mp4'] );
}