diff options
Diffstat (limited to 'extensions/TimedMediaHandler/handlers/OggHandler/File_Ogg/File/Ogg/Opus.php')
| -rw-r--r-- | extensions/TimedMediaHandler/handlers/OggHandler/File_Ogg/File/Ogg/Opus.php | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/extensions/TimedMediaHandler/handlers/OggHandler/File_Ogg/File/Ogg/Opus.php b/extensions/TimedMediaHandler/handlers/OggHandler/File_Ogg/File/Ogg/Opus.php new file mode 100644 index 00000000..2c23d928 --- /dev/null +++ b/extensions/TimedMediaHandler/handlers/OggHandler/File_Ogg/File/Ogg/Opus.php @@ -0,0 +1,126 @@ +<?php +/* vim: set expandtab tabstop=4 shiftwidth=4: */ +// +----------------------------------------------------------------------------+ +// | File_Ogg PEAR Package for Accessing Ogg Bitstreams | +// | Copyright (c) 2013 | +// | Jan Gerber <jgerber@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 | +// +----------------------------------------------------------------------------+ + + +define( 'OGG_OPUS_COMMENTS_PAGE_OFFSET', 1 ); + +/** + * @author Jan Gerber <jgerber@wikimedia.org> + * @category File + * @copyright Jan Gerber <jgerber@wikimedia.org> + * @license http://www.gnu.org/copyleft/lesser.html GNU LGPL + * @link http://pear.php.net/package/File_Ogg + * @link http://www.opus-codec.org/ + * @package File_Ogg + * @version 1 + */ +class File_Ogg_Opus extends File_Ogg_Media +{ + /** + * @access private + */ + function __construct($streamSerial, $streamData, $filePointer) + { + parent::__construct($streamSerial, $streamData, $filePointer); + $this->_decodeHeader(); + $this->_decodeCommentsHeader(); + + $endSec = $this->getSecondsFromGranulePos( $this->_lastGranulePos ); + $startSec = $this->getSecondsFromGranulePos( $this->_firstGranulePos ); + + if( $startSec > 1){ + $this->_streamLength = $endSec - $startSec; + $this->_startOffset = $startSec; + }else{ + $this->_streamLength = $endSec; + } + $this->_avgBitrate = $this->_streamLength ? ($this->_streamSize * 8) / $this->_streamLength : 0; + } + + function getSecondsFromGranulePos( $granulePos ){ + return (( '0x' . substr( $granulePos, 0, 8 ) ) * pow(2, 32) + + ( '0x' . substr( $granulePos, 8, 8 ) ) + - $this->_header['pre_skip']) + / 48000; + } + + /** + * Get a short string describing the type of the stream + * @return string + */ + function getType() + { + return 'Opus'; + } + + /** + * Decode the stream header + * @access private + */ + function _decodeHeader() + { + fseek($this->_filePointer, $this->_streamData['pages'][0]['body_offset'], SEEK_SET); + // The first 8 characters should be "OpusHead". + if (fread($this->_filePointer, 8) != 'OpusHead') + throw new OggException("Stream is undecodable due to a malformed header.", OGG_ERROR_UNDECODABLE); + + $this->_header = File_Ogg::_readLittleEndian($this->_filePointer, array( + 'opus_version' => 8, + 'nb_channels' => 8, + 'pre_skip' => 16, + 'audio_sample_rate' => 32, + 'output_gain' => 16, + 'channel_mapping_family'=> 8, + )); + $this->_channels = $this->_header['nb_channels']; + } + + /** + * Get an associative array containing header information about the stream + * @access public + * @return array + */ + function getHeader() { + return $this->_header; + } + + function getSampleRate() + { + //Opus always outputs 48kHz, the header only lists + //the samplerate of the source as reference + return 48000; + } + + /** + * Decode the comments header + * @access private + */ + function _decodeCommentsHeader() + { + $id = 'OpusTags'; + $this->_decodeCommonHeader(false, OGG_OPUS_COMMENTS_PAGE_OFFSET); + if(fread($this->_filePointer, strlen($id)) !== $id) + throw new OggException("Stream is undecodable due to a malformed header.", OGG_ERROR_UNDECODABLE); + $this->_decodeBareCommentsHeader(); + } +} +?> |