Composition Time to Sample Box provides the offset between * decoding time and composition time. Since decoding time must be less than the * composition time, the offsets are expressed as unsigned numbers such that * CT(n) = DT(n) + CTTS(n) where CTTS(n) is the (uncompressed) table entry for * sample n. * * The composition time to sample table is optional and must only be present if * DT and CT differ for any samples. Hint tracks do not use this box. * * @package php-reader * @subpackage ISO 14496 * @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: 92 $ */ final class ISO14496_Box_CTTS extends ISO14496_Box_Full { /** @var Array */ private $_compositionOffsetTable = 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++) $this->_compositionOffsetTable[$i] = array ("sampleCount" => Transform::fromUInt32BE(substr($data, ($i - 1) * 8, 4)), "sampleOffset" => Transform::fromUInt32BE(substr($data, $i * 8 - 4, 4))); } /** * Returns an array of values. Each entry is an array containing the following * keys. * o sampleCount -- an integer that counts the number of consecutive samples * that have the given offset. * o sampleOffset -- a non-negative integer that gives the offset between CT * and DT, such that CT(n) = DT(n) + CTTS(n). * * @return Array */ public function getCompositionOffsetTable() { return $this->_compositionOffsetTable; } }