Avoid double logarithmic volume scaling when using libxine >= 1.2.13. This relates to TDE/tdemultimedia#40

Signed-off-by: Michele Calgaro <michele.calgaro@yahoo.it>
(cherry picked from commit 41def34f87)

amarok/src/engine/xine/xine-engine.cpp

@@ -68,6 +68,7 @@ static inline TQCString configPath() { return TQFile::encodeName(locate( "data",
 static Fader *s_fader = 0;
 static OutFader *s_outfader = 0;
 
+bool XineEngine::s_logarithmicVolume = false;
 
 XineEngine::XineEngine()
         : EngineBase()
@@ -89,6 +90,12 @@ XineEngine::XineEngine()
     addPluginProperty("HasCDDA", "true"); // new property
     debug() << "hello" << endl;
 
+    // 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);
 }
 
 XineEngine::~XineEngine()
@@ -568,6 +575,15 @@ XineEngine::seek( uint ms )
     }
 }
 
+void
+XineEngine::setVolume( uint value )
+{
+    m_volume = value;
+
+    setVolumeSW( adjustVolume( value ) );
+}
+
+
 void
 XineEngine::setVolumeSW( uint vol )
 {
@@ -577,6 +593,19 @@ XineEngine::setVolumeSW( uint vol )
         xine_set_param( m_stream, XINE_PARAM_AUDIO_AMP_LEVEL, static_cast<uint>( vol * m_preamp ) );
 }
 
+// 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.
+uint
+XineEngine::adjustVolume( uint volume )
+{
+  if (s_logarithmicVolume)
+  {
+    return XineEngine::makeVolumeLogarithmic(volume);
+  }
+
+  return volume;
+}
+
 void
 XineEngine::fadeOut( uint fadeLength, bool* terminate, bool exiting )
 {
@@ -585,7 +614,7 @@ XineEngine::fadeOut( uint fadeLength, bool* terminate, bool exiting )
 
     m_fadeOutRunning = !m_fadeOutRunning;
     const bool isPlaying = m_stream && ( xine_get_status( m_stream ) == XINE_STATUS_PLAY );
-    const float originalVol = Engine::Base::makeVolumeLogarithmic( m_volume ) * m_preamp;
+    const float originalVol = adjustVolume( m_volume ) * m_preamp;
 
     // On shutdown, limit fadeout to 3 secs max, so that we don't risk getting killed
     const int length = exiting ? TQMIN( fadeLength, 3000 ) : fadeLength;
@@ -605,7 +634,7 @@ XineEngine::fadeOut( uint fadeLength, bool* terminate, bool exiting )
             if( *terminate ) break;
 
             ::usleep( stepSizeUs );
-            float vol = Engine::Base::makeVolumeLogarithmic( m_volume ) * m_preamp;
+            float vol = adjustVolume( m_volume ) * m_preamp;
             float mix = (float)t.elapsed() / (float)length;
             if ( mix > 1.0 )
             {
@@ -1294,7 +1323,7 @@ Fader::run()
         elapsedUs += stepSizeUs;
 
         // get volume (amarok main * equalizer preamp)
-        float vol = XineEngine::makeVolumeLogarithmic( m_engine->m_volume ) * m_engine->m_preamp;
+        float vol = XineEngine::adjustVolume( m_engine->m_volume ) * m_engine->m_preamp;
 
         // compute the mix factor as the percentage of time spent since fade begun
         float mix = (elapsedUs / 1000.0) / (float)m_fadeLength;

amarok/src/engine/xine/xine-engine.h

@@ -53,7 +53,10 @@ class XineEngine : public Engine::Base
     virtual Amarok::PluginConfig *configure() const;
     virtual void setEqualizerEnabled( bool );
     virtual void setEqualizerParameters( int preamp, const TQValueList<int>& );
+    virtual void setVolume( uint value );
     virtual void setVolumeSW( uint );
+    static  uint adjustVolume( uint volume );
+
     virtual void fadeOut( uint fadeLength, bool* terminate, bool exiting = false );
 
     static  void XineEventListener( void*, const xine_event_t* );
@@ -80,6 +83,7 @@ class XineEngine : public Engine::Base
     int64_t             m_currentVpts;
     float               m_preamp;
 
+    static bool         s_logarithmicVolume;
     bool                m_stopFader;
     bool                m_fadeOutRunning;
 

amarok/src/enginebase.h

@@ -179,7 +179,7 @@ namespace Engine
          * Set new volume value.
          * @param value Volume in range 0 to 100.
          */
-        void setVolume( uint value );
+        virtual void setVolume( uint value );
 
         /** Set new crossfade length (msec) */
         void setXfadeLength( int value ) { m_xfadeLength = value; }