plibreader/src/MPEG/Audio/VBRIHeader.php

<?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 MPEG
 * @copyright  Copyright (c) 2008 The PHP Reader Project Workgroup
 * @license    http://code.google.com/p/php-reader/wiki/License New BSD License
 * @version    $Id: VBRIHeader.php 1 2008-07-19 10:43:41Z rbutterfield $
 */

/**#@+ @ignore */
require_once("Reader.php");
require_once("Twiddling.php");
require_once("MPEG/Object.php");
/**#@-*/

/**
 * This class represents the Fraunhofer IIS VBR header which is often found in
 * the first frame of an MPEG stream.
 *
 * @package    php-reader
 * @subpackage MPEG
 * @author     Ryan Butterfield <buttza@gmail.com>
 * @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: 1 $
 */
class MPEG_Audio_VBRIHeader extends MPEG_Object
{
  /** @var integer */
  private $_version;
  
  /** @var integer */
  private $_delay;
  
  /** @var integer */
  private $_qualityIndicator;
  
  /** @var integer */
  private $_bytes;
  
  /** @var integer */
  private $_frames;
  
  /** @var Array */
  private $_toc = array();
  
  /** @var integer */
  private $_tocFramesPerEntry;
  
  /** @var integer */
  private $_length;
  
  /**
   * Constructs the class with given parameters and reads object related data
   * from the bitstream.
   *
   * @param Reader $reader The reader object.
   * @param Array $options Array of options.
   */
  public function __construct($reader, &$options = array())
  {
    $offset = $this->_reader->getOffset();
    $this->_version = $this->_reader->readUInt16BE();
    $this->_delay = $this->_reader->readUInt16BE();
    $this->_qualityIndicator = $this->_reader->readUInt16BE();
    $this->_bytes = $this->_reader->readUInt32BE();
    $this->_frames = $this->_reader->readUInt32BE();
    $tocEntries = $this->_reader->readUInt16BE();
    $tocEntryScale = $this->_reader->readUInt16BE();
    $tocEntrySize = $this->_reader->readUInt16BE();
    $this->_tocFramesPerEntry = $this->_reader->readUInt16BE();
    $this->_toc = array_merge(unpack(($tocEntrySize == 1) ? "C*" :
      ($tocEntrySize == 2) ? "n*" : "N*",
      $this->_reader->read($tocCount * $tocEntrySize)));
    foreach ($this->_toc as $key => $value)
      $this->_toc[$key] = $tocEntryScale * $value;
    $this->_length = $this->_reader->getOffset() - $offset;
  }

  /**
   * Returns the header version.
   *
   * @return integer
   */
  public function getVersion() { return $this->_version; }

  /**
   * Returns the delay.
   *
   * @return integer
   */
  public function getDelay() { return $this->_delay; }

  /**
   * Returns the quality indicator. Return value varies from 0 (best quality) to
   * 100 (worst quality).
   *
   * @return integer
   */
  public function getQualityIndicator() { return $this->_qualityIndicator; }

  /**
   * Returns the number of bytes in the file.
   *
   * @return integer
   */
  public function getBytes() { return $this->_bytes; }

  /**
   * Returns the number of frames in the file.
   *
   * @return integer
   */
  public function getFrames() { return $this->_frames; }

  /**
   * Returns the table of contents array.
   *
   * @return Array
   */
  public function getToc() { return $this->_toc; }

  /**
   * Returns the number of frames per TOC entry.
   *
   * @return integer
   */
  public function getTocFramesPerEntry() { return $this->_tocFramesPerEntry; }

  /**
   * Returns the length of the header in bytes.
   *
   * @return integer
   */
  public function getLength() { return $this->_length; }
}