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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 ISO 14496
* @copyright Copyright (c) 2008 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Id: STSC.php 92 2008-05-10 13:43:14Z svollbehr $
*/
/**#@+ @ignore */
require_once("ISO14496/Box/Full.php");
/**#@-*/
/**
* Samples within the media data are grouped into chunks. Chunks can be of
* different sizes, and the samples within a chunk can have different sizes.
* The <i>Sample To Chunk Box</i> table can be used to find the chunk that
* contains a sample, its position, and the associated sample description.
*
* The table is compactly coded. Each entry gives the index of the first chunk
* of a run of chunks with the same characteristics. By subtracting one entry
* here from the previous one, you can compute how many chunks are in this run.
* You can convert this to a sample count by multiplying by the appropriate
* samplesPerChunk.
*
* @package php-reader
* @subpackage ISO 14496
* @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: 92 $
*/
final class ISO14496_Box_STSC extends ISO14496_Box_Full
{
/** @var Array */
private $_sampleToChunkTable = array();
/**
* Constructs the class with given parameters and reads box related data from
* the ISO Base Media file.
*
* @param Reader $reader The reader object.
*/
public function __construct($reader, &$options = array())
{
parent::__construct($reader, $options);
$entryCount = $this->_reader->readUInt32BE();
$data = $this->_reader->read
($this->getOffset() + $this->getSize() - $this->_reader->getOffset());
for ($i = 1; $i <= $entryCount; $i++)
$this->_sampleToChunkTable[$i] = array
("firstChunk" =>
Transform::fromUInt32BE(substr($data, ($i - 1) * 12, 4)),
"samplesPerChunk" =>
Transform::fromUInt32BE(substr($data, $i * 12 - 8, 4)),
"sampleDescriptionIndex" =>
Transform::fromUInt32BE(substr($data, $i * 12 - 4, 4)));
}
/**
* Returns an array of values. Each entry is an array containing the following
* keys.
* o firstChunk -- an integer that gives the index of the first chunk in
* this run of chunks that share the same samplesPerChunk and
* sampleDescriptionIndex; the index of the first chunk in a track has the
* value 1 (the firstChunk field in the first record of this box has the
* value 1, identifying that the first sample maps to the first chunk).
* o samplesPerChunk is an integer that gives the number of samples in each
* of these chunks.
* o sampleDescriptionIndex is an integer that gives the index of the sample
* entry that describes the samples in this chunk. The index ranges from 1
* to the number of sample entries in the {@link ISO14496_Box_STSD Sample
* Description Box}.
*
* @return Array
*/
public function getSampleToChunkTable()
{
return $this->_sampleToChunkTable;
}
}
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