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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: SDTP.php 92 2008-05-10 13:43:14Z svollbehr $
*/
/**#@+ @ignore */
require_once("ISO14496/Box/Full.php");
/**#@-*/
/**
* The <i>Independent and Disposable Samples Box</i> optional table answers
* three questions about sample dependency:
* 1) does this sample depend on others (is it an I-picture)?
* 2) do no other samples depend on this one?
* 3) does this sample contain multiple (redundant) encodings of the data at
* this time-instant (possibly with different dependencies)?
*
* In the absence of this table:
* 1) the sync sample table answers the first question; in most video codecs,
* I-pictures are also sync points,
* 2) the dependency of other samples on this one is unknown.
* 3) the existence of redundant coding is unknown.
*
* When performing trick modes, such as fast-forward, it is possible to use the
* first piece of information to locate independently decodable samples.
* Similarly, when performing random access, it may be necessary to locate the
* previous sync point or random access recovery point, and roll-forward from
* the sync point or the pre-roll starting point of the random access recovery
* point to the desired point. While rolling forward, samples on which no others
* depend need not be retrieved or decoded.
*
* The value of sampleIsDependedOn is independent of the existence of redundant
* codings. However, a redundant coding may have different dependencies from the
* primary coding; if redundant codings are available, the value of
* sampleDependsOn documents only the primary coding.
*
* A sample dependency Box may also occur in the {@link ISO14496_Box_TRAF Track
* Fragment Box}.
*
* @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_SDTP extends ISO14496_Box_Full
{
/** @var Array */
private $_sampleDependencyTypeTable = 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);
$data = $this->_reader->read
($this->getOffset() + $this->getSize() - $this->_reader->getOffset());
$dataSize = strlen($data);
for ($i = 1; $i <= $dataSize; $i++)
$this->_sampleDependencyTypeTable[$i] = array
("sampleDependsOn" => (($tmp = Transform::fromInt8
($data[$i - 1])) >> 4) & 0x3,
"sampleIsDependedOn" => ($tmp >> 2) & 0x3,
"sampleHasRedundancy" => $tmp & 0x3);
}
/**
* Returns an array of values. Each entry is an array containing the following
* keys.
* o sampleDependsOn -- takes one of the following four values:
* 0: the dependency of this sample is unknown;
* 1: this sample does depend on others (not an I picture);
* 2: this sample does not depend on others (I picture);
* 3: reserved
* o sampleIsDependedOn -- takes one of the following four values:
* 0: the dependency of other samples on this sample is unknown;
* 1: other samples depend on this one (not disposable);
* 2: no other sample depends on this one (disposable);
* 3: reserved
* o sampleHasRedundancy -- takes one of the following four values:
* 0: it is unknown whether there is redundant coding in this sample;
* 1: there is redundant coding in this sample;
* 2: there is no redundant coding in this sample;
* 3: reserved
*
* @return Array
*/
public function getSampleDependencyTypeTable()
{
return $this->_sampleDependencyTypeTable;
}
}
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