getid3_ogg::TheoraColorSpace

	 * @return string|null
	 */
	public static function TheoraColorSpace($colorspace_id) {
		// http://www.theora.org/doc/Theora.pdf (table 6.3)
		static $TheoraColorSpaceLookup = array();
		if (empty($TheoraColorSpaceLookup)) {
			$TheoraColorSpaceLookup[0] = 'Undefined';
			$TheoraColorSpaceLookup[1] = 'Rec. 470M';
			$TheoraColorSpaceLookup[2] = 'Rec. 470BG';
			$TheoraColorSpaceLookup[3] = 'Reserved';
		}