Media Object Index Parameters Object supplies information about * those streams that actually indexed (there must be at least one stream in an * index) by media objects. This object shall be present in the * {@link ASF_Object_Header Header Object} if there is a * {@link ASF_Object_MediaObjectIndex Media Object Index Object} present in the * file. * * An Index Specifier is required for each stream that will be indexed by the * {@link ASF_Object_MediaObjectIndex Media Object Index Object}. These * specifiers must exactly match those in the * {@link ASF_Object_MediaObjectIndex Media Object Index Object}. * * @package php-reader * @subpackage ASF * @author Sven Vollbehr * @copyright Copyright (c) 2008 The PHP Reader Project Workgroup * @license http://code.google.com/p/php-reader/wiki/License New BSD License * @version $Rev: 108 $ */ final class ASF_Object_MediaObjectIndexParameters extends ASF_Object { /** @var string */ private $_indexEntryCountInterval; /** @var Array */ private $_indexSpecifiers = array(); /** * Constructs the class with given parameters and reads object related data * from the ASF file. * * @param Reader $reader The reader object. * @param Array $options The options array. */ public function __construct($reader, &$options = array()) { parent::__construct($reader, $options); $this->_indexEntryCountInterval = $this->_reader->readUInt32LE(); $indexSpecifiersCount = $this->_reader->readUInt16LE(); for ($i = 0; $i < $indexSpecifiersCount; $i++) { $this->_indexSpecifiers[] = array ("streamNumber" => $this->_reader->readUInt16LE(), "indexType" => $this->_reader->readUInt16LE()); } } /** * Returns the interval between each index entry by the number of media * objects. This value cannot be 0. * * @return integer */ public function getIndexEntryCountInterval() { return $this->_indexEntryCountInterval; } /** * Returns an array of index entries. Each entry consists of the following * keys. * * o streamNumber -- Specifies the stream number that the Index Specifiers * refer to. Valid values are between 1 and 127. * * o indexType -- Specifies the type of index. Values are defined as * follows: * 1 = Nearest Past Data Packet, * 2 = Nearest Past Media Object, * 3 = Nearest Past Cleanpoint, * 0xff = Frame Number Offset. * For a video stream, the Nearest Past Media Object and Nearest Past Data * Packet indexes point to the closest data packet containing an entire * video frame or first fragment of a video frame; Nearest Past Cleanpoint * indexes point to the closest data packet containing an entire video * frame (or first fragment of a video frame) that is a key frame; and * Frame Number Offset indicates how many more frames need to be read for * the given stream, starting with the first frame in the packet pointed * to by the index entry, in order to get to the requested frame. Nearest * Past Media Object is the most common value. Because ASF payloads do not * contain the full frame number, there is often a Frame Number Offset * index alongside one of the other types of indexes to allow the user to * identify the exact frame being seeked to. * * @return Array */ public function getIndexSpecifiers() { return $this->_indexSpecifiers; } }