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<?php
/**
* PHP Reader Library
*
* Copyright (c) 2008 The PHP Reader Project Workgroup. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of the project workgroup nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* @package php-reader
* @subpackage ASF
* @copyright Copyright (c) 2008 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Id: MediaObjectIndex.php 108 2008-09-05 17:00:05Z svollbehr $
*/
/**#@+ @ignore */
require_once("ASF/Object.php");
/**#@-*/
/**
* This top-level ASF object supplies media object indexing information for the
* streams of an ASF file. It includes stream-specific indexing information
* based on an adjustable index entry media object count interval. This object
* can be used to index all the video frames or key frames in a video stream.
* The index is designed to be broken into blocks to facilitate storage that is
* more space-efficient by using 32-bit offsets relative to a 64-bit base. That
* is, each index block has a full 64-bit offset in the block header that is
* added to the 32-bit offset found in each index entry. If a file is larger
* than 2^32 bytes, then multiple index blocks can be used to fully index the
* entire large file while still keeping index entry offsets at 32 bits.
*
* Indices into the <i>Media Object Index Object</i> are in terms of media
* object numbers, with the first frame for a given stream in the ASF file
* corresponding to entry 0 in the <i>Media Object Index Object</i>. The
* corresponding <i>Offset</i> field values of the <i>Index Entry</i> are byte
* offsets that, when combined with the <i>Block Position</i> value of the
* Index Block, indicate the starting location in bytes of an ASF Data Packet
* relative to the start of the first ASF Data Packet in the file.
*
* Any ASF file containing a <i>Media Object Index Object</i> shall also contain
* a <i>Media Object Index Parameters Object</i> in its
* {@link ASF_Object_Header ASF Header}.
*
* @package php-reader
* @subpackage ASF
* @author Sven Vollbehr <svollbehr@gmail.com>
* @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_MediaObjectIndex extends ASF_Object
{
/**
* Indicates that the index type is Nearest Past Data Packet. The Nearest
* Past Data Packet indexes point to the data packet whose presentation time
* is closest to the index entry time.
*/
const NEAREST_PAST_DATA_PACKET = 1;
/**
* Indicates that the index type is Nearest Past Media. The Nearest Past
* Object indexes point to the closest data packet containing an entire object
* or first fragment of an object.
*/
const NEAREST_PAST_MEDIA = 2;
/**
* Indicates that the index type is Nearest Past Cleanpoint. The Nearest Past
* Cleanpoint indexes point to the closest data packet containing an entire
* object (or first fragment of an object) that has the Cleanpoint Flag set.
*
* Nearest Past Cleanpoint is the most common type of index.
*/
const NEAREST_PAST_CLEANPOINT = 3;
/** @var integer */
private $_indexEntryCountInterval;
/** @var Array */
private $_indexSpecifiers = array();
/** @var Array */
private $_indexBlocks = 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();
$indexBlocksCount = $this->_reader->readUInt32LE();
for ($i = 0; $i < $indexSpecifiersCount; $i++)
$this->_indexSpecifiers[] = array
("streamNumber" => $this->_reader->readUInt16LE(),
"indexType" => $this->_reader->readUInt16LE());
for ($i = 0; $i < $indexBlocksCount; $i++) {
$indexEntryCount = $this->_reader->readUInt32LE();
$blockPositions = array();
for ($i = 0; $i < $indexSpecifiersCount; $i++)
$blockPositions[] = $this->_reader->readInt64LE();
$offsets = array();
for ($i = 0; $i < $indexSpecifiersCount; $i++)
$offsets[] = $this->_reader->readUInt32LE();
$this->_indexBlocks[] = array
("blockPositions" => $blockPositions,
"indexEntryOffsets" => $offsets);
}
}
/**
* Returns the interval between each index entry in number of media objects.
*
* @return integer
*/
public function getIndexEntryCountInterval()
{
return $this->_indexEntryCountInterval;
}
/**
* Returns an array of index specifiers. Each entry consists of the following
* keys.
*
* o streamNumber -- Specifies the stream number that the <i>Index
* Specifiers</i> refer to. Valid values are between 1 and 127.
*
* o indexType -- Specifies the type of index.
*
* @return Array
*/
public function getIndexSpecifiers() { return $this->_indexSpecifiers; }
/**
* Returns an array of index entries. Each entry consists of the following
* keys.
*
* o blockPositions -- Specifies a list of byte offsets of the beginnings of
* the blocks relative to the beginning of the first Data Packet (for
* example, the beginning of the Data Object + 50 bytes).
*
* o indexEntryOffsets -- Specifies the offset. An offset value of
* 0xffffffff indicates an invalid offset value.
*
* @return Array
*/
public function getIndexBlocks() { return $this->_indexBlocks; }
}
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