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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4: */
// +----------------------------------------------------------------------------+
// | File_Ogg PEAR Package for Accessing Ogg Bitstreams |
// | Copyright (c) 2005-2007 |
// | David Grant <david@grant.org.uk> |
// | Tim Starling <tstarling@wikimedia.org> |
// +----------------------------------------------------------------------------+
// | This library is free software; you can redistribute it and/or |
// | modify it under the terms of the GNU Lesser General Public |
// | License as published by the Free Software Foundation; either |
// | version 2.1 of the License, or (at your option) any later version. |
// | |
// | This library is distributed in the hope that it will be useful, |
// | but WITHOUT ANY WARRANTY; without even the implied warranty of |
// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
// | Lesser General Public License for more details. |
// | |
// | You should have received a copy of the GNU Lesser General Public |
// | License along with this library; if not, write to the Free Software |
// | Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
// +----------------------------------------------------------------------------+
/**
* @author David Grant <david@grant.org.uk>, Tim Starling <tstarling@wikimedia.org>
* @category File
* @copyright David Grant <david@grant.org.uk>, Tim Starling <tstarling@wikimedia.org>
* @license http://www.gnu.org/copyleft/lesser.html GNU LGPL
* @link http://pear.php.net/package/File_Ogg
* @link http://flac.sourceforge.net/documentation.html
* @package File_Ogg
* @version CVS: $Id: Flac.php,v 1.9 2005/11/16 20:43:27 djg Exp $
*/
class File_Ogg_Flac extends File_Ogg_Media
{
/**
* @access private
*/
function __construct($streamSerial, $streamData, $filePointer)
{
parent::__construct($streamSerial, $streamData, $filePointer);
$this->_decodeHeader();
$this->_decodeCommentsHeader();
$this->_streamLength = $this->_streamInfo['total_samples']
/ $this->_streamInfo['sample_rate'];
}
/**
* Get a short string describing the type of the stream
* @return string
*/
function getType() {
return 'FLAC';
}
/**
* @access private
* @param int $packetType
* @param int $pageOffset
*/
function _decodeHeader()
{
fseek($this->_filePointer, $this->_streamData['pages'][0]['body_offset'], SEEK_SET);
// Check if this is the correct header.
$packet = unpack("Cdata", fread($this->_filePointer, 1));
if ($packet['data'] != 0x7f)
throw new OggException("Stream Undecodable", OGG_ERROR_UNDECODABLE);
// The following four characters should be "FLAC".
if (fread($this->_filePointer, 4) != 'FLAC')
throw new OggException("Stream is undecodable due to a malformed header.", OGG_ERROR_UNDECODABLE);
$version = unpack("Cmajor/Cminor", fread($this->_filePointer, 2));
$this->_version = "{$version['major']}.{$version['minor']}";
if ($version['major'] > 1) {
throw new OggException("Cannot decode a version {$version['major']} FLAC stream", OGG_ERROR_UNDECODABLE);
}
$h = File_Ogg::_readBigEndian( $this->_filePointer,
array(
// Ogg-specific
'num_headers' => 16,
'flac_native_sig' => 32,
// METADATA_BLOCK_HEADER
'is_last' => 1,
'type' => 7,
'length' => 24,
));
// METADATA_BLOCK_STREAMINFO
// The variable names are canonical, and come from the FLAC source (format.h)
$this->_streamInfo = File_Ogg::_readBigEndian( $this->_filePointer,
array(
'min_blocksize' => 16,
'max_blocksize' => 16,
'min_framesize' => 24,
'max_framesize' => 24,
'sample_rate' => 20,
'channels' => 3,
'bits_per_sample' => 5,
'total_samples' => 36,
));
$this->_streamInfo['md5sum'] = bin2hex(fread($this->_filePointer, 16));
}
/**
* Get an associative array containing header information about the stream
* @access public
* @return array
*/
function getHeader()
{
return $this->_streamInfo;
}
function _decodeCommentsHeader()
{
fseek($this->_filePointer, $this->_streamData['pages'][1]['body_offset'], SEEK_SET);
$blockHeader = File_Ogg::_readBigEndian( $this->_filePointer,
array(
'last_block' => 1,
'block_type' => 7,
'length' => 24
)
);
if ($blockHeader['block_type'] != 4) {
throw new OggException("Stream Undecodable", OGG_ERROR_UNDECODABLE);
}
$this->_decodeBareCommentsHeader();
}
}
?>
|
