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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 ID3
* @copyright Copyright (c) 2008 The PHP Reader Project Workgroup
* @license http://code.google.com/p/php-reader/wiki/License New BSD License
* @version $Id: RVA2.php 105 2008-07-30 14:56:47Z svollbehr $
* @since ID3v2.4.0
*/
/**#@+ @ignore */
require_once("ID3/Frame.php");
/**#@-*/
/**
* The <i>Relative volume adjustment (2)</i> frame is a more subjective frame than
* the previous ones. It allows the user to say how much he wants to
* increase/decrease the volume on each channel when the file is played. The
* purpose is to be able to align all files to a reference volume, so that you
* don't have to change the volume constantly. This frame may also be used to
* balance adjust the audio. The volume adjustment is encoded as a fixed point
* decibel value, 16 bit signed integer representing (adjustment*512), giving
* +/- 64 dB with a precision of 0.001953125 dB. E.g. +2 dB is stored as $04 00
* and -2 dB is $FC 00.
*
* There may be more than one RVA2 frame in each tag, but only one with the same
* identification string.
*
* @package php-reader
* @subpackage ID3
* @author Sven Vollbehr <svollbehr@gmail.com>
* @author Ryan Butterfield <buttza@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: 105 $
* @since ID3v2.4.0
*/
final class ID3_Frame_RVA2 extends ID3_Frame
{
/**
* The channel type key.
*
* @see $types
* @var string
*/
const channelType = "channelType";
/**
* The volume adjustment key. Adjustments are +/- 64 dB with a precision of
* 0.001953125 dB.
*
* @var string
*/
const volumeAdjustment = "volumeAdjustment";
/**
* The peak volume key.
*
* @var string
*/
const peakVolume = "peakVolume";
/**
* The list of channel types.
*
* @var Array
*/
public static $types = array
("Other", "Master volume", "Front right", "Front left", "Back right",
"Back left", "Front centre", "Back centre", "Subwoofer");
/** @var string */
private $_device;
/** @var Array */
private $_adjustments;
/**
* Constructs the class with given parameters and parses object related data.
*
* @param Reader $reader The reader object.
* @param Array $options The options array.
*/
public function __construct($reader = null, &$options = array())
{
parent::__construct($reader, $options);
if ($reader === null)
return;
list ($this->_device, $this->_data) =
$this->explodeString8($this->_data, 2);
for ($i = $j = 0; $i < 9; $i++) {
$this->_adjustments[$i] = array
(self::channelType => Transform::fromInt8($this->_data[$j++]),
self::volumeAdjustment =>
Transform::fromInt16BE(substr($this->_data, $j++, 2)) / 512.0);
$j++;
$bitsInPeak = Transform::fromInt8($this->_data[$j++]);
$bytesInPeak = $bitsInPeak > 0 ? ceil($bitsInPeak / 8) : 0;
switch ($bytesInPeak) {
case 8:
case 7:
case 6:
case 5:
$this->_adjustments[$i][self::peakVolume] =
Transform::fromInt64BE(substr($this->_data, $j, $bytesInPeak));
break;
case 4:
case 3:
$this->_adjustments[$i][self::peakVolume] =
Transform::fromUInt32BE(substr($this->_data, $j, $bytesInPeak));
break;
case 2:
$this->_adjustments[$i][self::peakVolume] =
Transform::fromUInt16BE(substr($this->_data, $j, $bytesInPeak));
break;
case 1:
$this->_adjustments[$i][self::peakVolume] =
Transform::fromUInt8(substr($this->_data, $j, $bytesInPeak));
}
$j += $bytesInPeak;
}
}
/**
* Returns the device where the adjustments should apply.
*
* @return string
*/
public function getDevice() { return $this->_device; }
/**
* Sets the device where the adjustments should apply.
*
* @param string $device The device.
*/
public function setDevice($device) { $this->_device = $device; }
/**
* Returns the array containing volume adjustments for each channel. Volume
* adjustments are arrays themselves containing the following keys:
* channelType, volumeAdjustment, peakVolume.
*
* @return Array
*/
public function getAdjustments() { return $this->_adjustments; }
/**
* Sets the array of volume adjustments for each channel. Each volume
* adjustment is an array too containing the following keys: channelType,
* volumeAdjustment, peakVolume.
*
* @param Array $adjustments The volume adjustments array.
*/
public function setAdjustments($adjustments)
{
$this->_adjustments = $adjustments;
}
/**
* Returns the frame raw data.
*
* @return string
*/
public function __toString()
{
$data = $this->_device . "\0";
foreach ($this->_adjustments as $channel) {
$data .= Transform::toInt8($channel[self::channelType]) .
Transform::toInt16BE($channel[self::volumeAdjustment] * 512);
if (abs($channel[self::peakVolume]) <= 0xff)
$data .= Transform::toInt8(8) .
Transform::toUInt8($channel[self::peakVolume]);
else if (abs($channel[self::peakVolume]) <= 0xffff)
$data .= Transform::toInt8(16) .
Transform::toUInt16BE($channel[self::peakVolume]);
else if (abs($channel[self::peakVolume]) <= 0xffffffff)
$data .= Transform::toInt8(32) .
Transform::toUInt32BE($channel[self::peakVolume]);
else
$data .= Transform::toInt8(64) .
Transform::toInt64BE($channel[self::peakVolume]); // UInt64
}
$this->setData($data);
return parent::__toString();
}
}
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