File indexing completed on 2025-01-19 04:24:47

 /****************************************************************************************
  * Copyright (c) 2010 Téo Mrnjavac <teo@kde.org>                                        *
  *                                                                                      *
  * This program is free software; you can redistribute it and/or modify it under        *
  * the terms of the GNU General Public License as published by the Free Software        *
  * Foundation; either version 2 of the License, or (at your option) any later           *
  * version.                                                                             *
  *                                                                                      *
  * This program 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 General Public License for more details.             *
  *                                                                                      *
  * You should have received a copy of the GNU General Public License along with         *
  * this program.  If not, see <http://www.gnu.org/licenses/>.                           *
  ****************************************************************************************/
 
 #include "TranscodingVorbisFormat.h"
 
 #include <KLocalizedString>
 
 using namespace Transcoding;
 
 VorbisFormat::VorbisFormat()
 {
     m_encoder = VORBIS;
     m_fileExtension = QStringLiteral("ogg");
     const QString description1 =
         i18n( "The bitrate is a measure of the quantity of data used to represent a "
         "second of the audio track.<br>The <b>Vorbis</b> encoder used by Amarok supports "
         "a <a href=http://en.wikipedia.org/wiki/Vorbis#Technical_details>variable bitrate "
         "(VBR)</a> setting, which means that the bitrate value fluctuates along the track "
         "based on the complexity of the audio content. More complex intervals of "
         "data are encoded with a higher bitrate than less complex ones; this "
         "approach yields overall better quality and a smaller file than having a "
         "constant bitrate throughout the track.<br>"
         "The Vorbis encoder uses a quality rating \"-q parameter\" between -1 and 10 to define "
         "a certain expected audio quality level. The bitrate measure in this slider is "
         "just a rough estimate (provided by Vorbis) of the average bitrate of the encoded "
         "track given a q value. In fact, with newer and more efficient Vorbis versions the "
         "actual bitrate is even lower.<br>"
         "<b>-q5</b> is a good choice for music listening on a portable player.<br/>"
         "Anything below <b>-q3</b> might be unsatisfactory for music and anything above "
         "<b>-q8</b> is probably overkill.");
     QStringList valueLabels;
     const QByteArray vbr = "-q%1 ~%2kb/s";
     valueLabels
         << i18n( vbr, -1, 45 )
         << i18n( vbr, 0, 64 )
         << i18n( vbr, 1, 80 )
         << i18n( vbr, 2, 96 )
         << i18n( vbr, 3, 112 )
         << i18n( vbr, 4, 128 )
         << i18n( vbr, 5, 160 )
         << i18n( vbr, 6, 192 )
         << i18n( vbr, 7, 224 )
         << i18n( vbr, 8, 256 )
         << i18n( vbr, 9, 320 )
         << i18n( vbr, 10, 500 );
     m_propertyList << Property::Tradeoff( "quality", i18n( "Quality rating for variable bitrate encoding" ), description1,
                                           i18n( "Smaller file" ), i18n( "Better sound quality" ),
                                           valueLabels, 7 );
 }
 
 QString
 VorbisFormat::prettyName() const
 {
     return i18n( "Ogg Vorbis" );
 }
 
 QString
 VorbisFormat::description() const
 {
     return i18nc( "Feel free to redirect the english Wikipedia link to a local version, if "
                   "it exists.",
                   "<a href=http://en.wikipedia.org/wiki/Vorbis>Ogg Vorbis</a> is an open "
                   "and royalty-free audio codec for lossy audio compression.<br>It produces "
                   "smaller files than MP3 at equivalent or higher quality. Ogg Vorbis is an "
                   "all-around excellent choice, especially for portable music players that "
                   "support it." );
 }
 
 QIcon
 VorbisFormat::icon() const
 {
     return QIcon::fromTheme( QStringLiteral("audio-x-wav") );  //TODO: get a *real* icon!
 }
 
 QStringList
 VorbisFormat::ffmpegParameters( const Configuration &configuration ) const
 {
     QStringList parameters;
     parameters << QStringLiteral("-acodec") << QStringLiteral("libvorbis");   //libvorbis is better than FFmpeg's
                                               //vorbis implementation in many ways
     foreach( const Property &property, m_propertyList )
     {
         if( !configuration.property( property.name() ).isNull()
             && configuration.property( property.name() ).type() == property.variantType() )
         {
             if( property.name() == "quality" )
             {
                 int ffmpegQuality = configuration.property( "quality" ).toInt() - 1;
                 parameters << QStringLiteral("-aq") << QString::number( ffmpegQuality );
             }
         }
     }
     parameters << QStringLiteral("-vn"); // no video stream or album art, some devices can't handle that
     return parameters;
 }
 
 bool
 VorbisFormat::verifyAvailability( const QString &ffmpegOutput ) const
 {
     return ffmpegOutput.contains( QRegExp( QStringLiteral("^ .EA... vorbis +.*libvorbis") ) );
 }