xine engine: make volume control logarithmic for versions of xine < 1.2.13. For xine versions >= 1.2.13, libxine already makes the volume logarithmic. This relates to TDE/tdemultimedia#40.

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit b5977d5e67)

src/app/mainWindow.cpp

@@ -265,7 +265,7 @@ MainWindow::setupActions()
 
    (new KWidgetAction( m_positionSlider, i18n("Position Slider"), 0, 0, 0, ac, "position_slider" ))->setAutoSized( true );
 
-   new VolumeAction( toolBar(), ac );
+   m_volumeAction = new VolumeAction( toolBar(), ac );
 }
 
 void

src/app/mainWindow.h

@@ -11,6 +11,7 @@ class KURL;
 class TQLabel;
 class TQPopupMenu;
 class TQSlider;
+class VolumeAction;
 
 
 namespace Codeine
@@ -65,6 +66,7 @@ namespace Codeine
       TQLabel  *m_timeLabel;
       TQLabel  *m_titleLabel;
       TQWidget *m_analyzer;
+      VolumeAction *m_volumeAction;
 
       //undefined
       MainWindow( const MainWindow& );

src/app/stateChange.cpp

@@ -16,6 +16,7 @@
 #include "theStream.h"
 #include "videoSettings.h" //FIXME unfortunate
 #include "xineEngine.h"
+#include "volumeAction.h"
 
 
 //TODO do in Sconstruct
@@ -62,9 +63,7 @@ MainWindow::engineStateChanged( Engine::State state )
       toggleAction( "play" )->setChecked( state == Playing );
 
       //FIXME bad design to do this way
-      TQSlider *volume = (TQSlider*)toolBar()->child( "volume" );
-      if (volume)
-         volume->setValue( engine()->volume() );
+      m_volumeAction->sliderMoved( engine()->volume() );
    }
 
 

src/app/volumeAction.cpp

@@ -77,7 +77,7 @@ VolumeAction::toggled( bool const b )
 {
    DEBUG_BLOCK
 
-   TQString t = TQString::number(Codeine::engine()->volume()) + "%";
+   TQString t = TQString::number(100 - m_widget->slider->value()) + "%";
    setToolTip( i18n( "Volume: %1" ).arg( t ) );
    m_widget->label->setText( t );
 

src/app/volumeAction.h

@@ -17,9 +17,11 @@ class VolumeAction : public TDEToggleAction
 
    virtual int plug( TQWidget*, int );
 
+public slots:
+   void sliderMoved( int );
+
 private slots:
    void toggled( bool );
-   void sliderMoved( int );
    void sliderReleased() { setChecked( false ); toggled( false ); }
 
 public:

src/app/xineEngine.cpp

@@ -26,6 +26,7 @@ namespace Codeine {
 
 
 VideoWindow *VideoWindow::s_instance = 0;
+bool VideoWindow::s_logarithmicVolume = false;
 
 
 VideoWindow::VideoWindow( TQWidget *parent )
@@ -53,6 +54,13 @@ VideoWindow::VideoWindow( TQWidget *parent )
    //TODO sucks
    //TODO namespace this?
    myList->next = myList; //init the buffer list
+
+   // Detect xine version, this is used for volume adjustment.
+   // Xine versions prior to 1.2.13 use linear volume, so the engine uses logarithmic volume.
+   // Xine versions starting from 1.2.13 use logarithmic volume, so the engine uses linear volume.
+   int xinemajor = 0, xineminor = 0, xinemaint = 0;
+   xine_get_version(&xinemajor, &xineminor, &xinemaint);
+   s_logarithmicVolume = (xinemajor * 1000000 + xineminor * 1000 + xinemaint < 1002013);
 }
 
 VideoWindow::~VideoWindow()
@@ -65,7 +73,12 @@ VideoWindow::~VideoWindow()
    if( m_stream && xine_get_status( m_stream ) == XINE_STATUS_PLAY ) {
       int cum = 0;
       for( int v = 99; v >= 0; v-- ) {
-         xine_set_param( m_stream, XINE_PARAM_AUDIO_AMP_LEVEL, v );
+         int vol = v;
+         if (s_logarithmicVolume)
+         {
+           vol = makeVolumeLogarithmic(vol);
+         }
+         xine_set_param( m_stream, XINE_PARAM_AUDIO_AMP_LEVEL, vol );
          int sleep = int(32000 * (-std::log10( double(v + 1) ) + 2));
 
          ::usleep( sleep );
@@ -255,6 +268,7 @@ VideoWindow::load( const KURL &url )
       setParameter( XINE_PARAM_SPU_CHANNEL, -1 );
       setParameter( XINE_PARAM_AUDIO_CHANNEL_LOGICAL, -1 );
       setParameter( XINE_PARAM_VO_ASPECT_RATIO, 0 );
+      // 100 is the same for both linear and logarithmic volume control
       setParameter( XINE_PARAM_AUDIO_AMP_LEVEL, 100 );
       #undef setParameter
 
@@ -445,8 +459,20 @@ VideoWindow::posTimeLength( PosTimeLength type ) const
 uint
 VideoWindow::volume() const
 {
-   //TODO I don't like the design
-   return xine_get_param( m_stream, XINE_PARAM_AUDIO_AMP_LEVEL );
+   int vol = xine_get_param( m_stream, XINE_PARAM_AUDIO_AMP_LEVEL );
+   if (s_logarithmicVolume)
+   {
+      vol = 100 - 100.0 * (pow(10, (100.0 - vol) / 100.0) - 1) / 9.0;
+   }
+   if (vol < 0)
+   {
+      vol = 0;
+   }
+   if (vol > 100)
+   {
+      vol = 100;
+   }
+   return (uint)vol;
 }
 
 void
@@ -532,6 +558,13 @@ VideoWindow::seek( uint pos )
       xine_set_param( m_stream, XINE_PARAM_AUDIO_AMP_MUTE, 0 );
 }
 
+int
+VideoWindow::makeVolumeLogarithmic(int volume)
+{
+   // We're using a logarithmic function to make the volume ramp more natural.
+   return static_cast<uint>( 100 - 100.0 * std::log10( ( 100 - volume ) * 0.09 + 1.0 ) );
+}
+
 void
 VideoWindow::setStreamParameter( int value )
 {
@@ -558,6 +591,10 @@ VideoWindow::setStreamParameter( int value )
    {
       parameter = XINE_PARAM_AUDIO_AMP_LEVEL;
       value = 100 - value; // TQt sliders are wrong way round when vertical
+      if (s_logarithmicVolume)
+      {
+        value = makeVolumeLogarithmic(value);
+      }
    }
    else
       return;

src/app/xineEngine.h

@@ -39,6 +39,7 @@ namespace Codeine
       enum PosTimeLength { Pos, Time, Length };
 
       static VideoWindow *s_instance;
+      static bool s_logarithmicVolume;
 
       VideoWindow( const VideoWindow& ); //disable
       VideoWindow &operator=( const VideoWindow& ); //disable
@@ -120,6 +121,7 @@ namespace Codeine
    private:
       static void destSizeCallBack( void*, int, int, double, int*, int*, double* );
       static void frameOutputCallBack( void*, int, int, double, int*, int*, int*, int*, double*, int*, int* );
+      static int makeVolumeLogarithmic(int volume);
 
       void initVideo();
       void cleanUpVideo();