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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: STSH.php 92 2008-05-10 13:43:14Z svollbehr $
*/
/**#@+ @ignore */
require_once("ISO14496/Box/Full.php");
/**#@-*/
/**
* The <i>Shadow Sync Sample Box</i> table provides an optional set of sync
* samples that can be used when seeking or for similar purposes. In normal
* forward play they are ignored.
*
* Each entry in the Shadow Sync Table consists of a pair of sample numbers. The
* first entry (shadowedSampleNumber) indicates the number of the sample that a
* shadow sync will be defined for. This should always be a non-sync sample
* (e.g. a frame difference). The second sample number (syncSampleNumber)
* indicates the sample number of the sync sample (i.e. key frame) that can be
* used when there is a random access at, or before, the shadowedSampleNumber.
*
* The shadow sync samples are normally placed in an area of the track that is
* not presented during normal play (edited out by means of an edit list),
* though this is not a requirement. The shadow sync table can be ignored and
* the track will play (and seek) correctly if it is ignored (though perhaps not
* optimally).
*
* The Shadow Sync Sample replaces, not augments, the sample that it shadows
* (i.e. the next sample sent is shadowedSampleNumber+1). The shadow sync sample
* is treated as if it occurred at the time of the sample it shadows, having the
* duration of the sample it shadows.
*
* Hinting and transmission might become more complex if a shadow sample is used
* also as part of normal playback, or is used more than once as a shadow. In
* this case the hint track might need separate shadow syncs, all of which can
* get their media data from the one shadow sync in the media track, to allow
* for the different time-stamps etc. needed in their headers.
*
* @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_STSH extends ISO14496_Box_Full
{
/** @var Array */
private $_shadowSyncSampleTable = 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 = 0; $i < $entryCount; $i++)
$this->_shadowSyncSampleTable[$i] = array
("shadowedSampleNumber" =>
Transform::fromUInt32BE(substr($data, ($i - 1) * 8, 4)),
"syncSampleNumber" =>
Transform::fromUInt32BE(substr($data, $i * 8 - 4, 4)));
}
/**
* Returns an array of values. Each entry is an array containing the following
* keys.
* o shadowedSampleNumber - gives the number of a sample for which there is
* an alternative sync sample.
* o syncSampleNumber - gives the number of the alternative sync sample.
*
* @return Array
*/
public function getShadowSyncSampleTable()
{
return $this->_shadowSyncSampleTable;
}
}
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