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 <[email protected]>
(cherry picked from commit b5977d5e67d68ec18fad1d1130f5a306ce4fe598)

1 files changed, 40 insertions, 3 deletions

diff --git a/src/app/xineEngine.cpp b/src/app/xineEngine.cpp
index 74f4f35..3a05862 100644
--- a/src/app/xineEngine.cpp
+++ b/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;