Bug 122514

I can confirm this with the xine engine.
It looks like the second track is recognised as having started playing at the beginning of the xfade, resulting in two concurrent playback threads - if pause is hit in this xfade period, the fade-out of the first track is what is actually paused, while the fade-in and playback of the second track continues. 
This seems to confuse the button state, so that the pause state is still on for the first inactive track.
Hitting pause after this doesn't seem to do anything useful.
Expected behaviour would be to pause playback of all tracks.

I can also confirm this with xine and alsa output with crossfade enabled with the latest svn (22/04/06). I hope this one gets fixed.

Attached a patch solving the issue

Note:
On some places in XineEngine the call to xine_get_param( m_stream, XINE_PARAM_SPEED ) is checked against 0
0 is defined in the xine header as XINE_SPEED_PAUSE.
I've replaced the 0 check with XINE_SPEED_PAUSE, as that is more safe.
The value of XINE_SPEED_PAUSE is xine internal, and could change in the future.

Created attachment 17549 [details]
Patch solving the issue

Created attachment 17550 [details]
Patch solving the issue

Ooops,
In case of stopping the current track or quitting amarok in the xfade pause
state, the fade thread thread should go on, otherwise we end up in an endless
loop.
Patch corrected

Created attachment 17551 [details]
Patch solving the issue

Sorry,
I've forgot to save the patch in the editor.
Now the correct patch should have been appended

SVN commit 586431 by markey:

This patch by Markus Kaufhold <M.Kaufhold@gmx.de> solves the following problem:
"Pause during crossfade using xine causes the next song to continue playing."

Also it provides a number of safety code improvements.

BUG: 122514


 M  +31 -6     xine-engine.cpp  
 M  +3 -0      xine-engine.h  


--- trunk/extragear/multimedia/amarok/src/engine/xine/xine-engine.cpp #586430:586431
@@ -35,7 +35,6 @@
 
 #include <qapplication.h>
 #include <qdir.h>
-#include <qtimer.h>
 
 extern "C"
 {
@@ -93,6 +92,7 @@
     // Wait until the fader thread is done
     if( s_fader ) {
         m_stopFader = true;
+        s_fader->resume(); // safety call if the engine is in the pause state
         s_fader->wait();
         delete s_fader;
     }
@@ -349,6 +349,9 @@
 void
 XineEngine::stop()
 {
+    if( s_fader && s_fader->running() )
+        s_fader->resume(); // safety call if the engine is in the pause state
+
     if ( !m_stream )
        return;
     if( !m_fadeOutRunning || state() == Engine::Paused )
@@ -367,14 +370,20 @@
 void
 XineEngine::pause()
 {
-    if( xine_get_param( m_stream, XINE_PARAM_SPEED ) )
+    if( xine_get_param( m_stream, XINE_PARAM_SPEED ) != XINE_SPEED_PAUSE )
     {
+        if( s_fader && s_fader->running() )
+            s_fader->pause();
+
         xine_set_param( m_stream, XINE_PARAM_SPEED, XINE_SPEED_PAUSE ); 
         xine_set_param( m_stream, XINE_PARAM_AUDIO_CLOSE_DEVICE, 1);
         emit stateChanged( Engine::Paused );
 
     } else {
 
+        if( s_fader && s_fader->running() )
+            s_fader->resume();
+
         xine_set_param( m_stream, XINE_PARAM_SPEED, XINE_SPEED_NORMAL );
         emit stateChanged( Engine::Playing );
     }
@@ -388,7 +397,7 @@
 
     switch( xine_get_status( m_stream ) )
     {
-    case XINE_STATUS_PLAY: return xine_get_param( m_stream, XINE_PARAM_SPEED ) ? Engine::Playing : Engine::Paused;
+    case XINE_STATUS_PLAY: return xine_get_param( m_stream, XINE_PARAM_SPEED )  != XINE_SPEED_PAUSE ? Engine::Playing : Engine::Paused;
     case XINE_STATUS_IDLE: return Engine::Empty;
     case XINE_STATUS_STOP:
     default:               return m_url.isEmpty() ? Engine::Empty : Engine::Idle;
@@ -991,6 +1000,7 @@
    , m_port( engine->m_audioPort )
    , m_post( engine->m_post )
    , m_fadeLength( fadeMs )
+   , m_paused( false )
 {
     if( engine->makeNewStream() )
     {
@@ -1029,19 +1039,23 @@
     uint stepsCount = m_fadeLength < 1000 ? m_fadeLength / 10 : 100;
     uint stepSizeUs = (int)( 1000.0 * (float)m_fadeLength / (float)stepsCount );
 
-    QTime t;
-    t.start();
     float mix = 0.0;
+    float elapsedUs = 0.0;
     while ( mix < 1.0 )
     {
         // sleep a constant amount of time
         QThread::usleep( stepSizeUs );
 
+        if ( m_paused )
+        	continue;
+
+        elapsedUs += stepSizeUs;
+
         // get volume (amarok main * equalizer preamp)
         float vol = Engine::Base::makeVolumeLogarithmic( m_engine->m_volume ) * m_engine->m_preamp;
 
         // compute the mix factor as the percentage of time spent since fade begun
-        float mix = (float)t.elapsed() / (float)m_fadeLength;
+        float mix = (elapsedUs / 1000.0) / (float)m_fadeLength;
         if ( mix > 1.0 )
         {
             if ( m_increase )
@@ -1117,7 +1131,18 @@
     deleteLater();
 }
 
+void
+Fader::pause()
+{
+	m_paused = true;
+}
 
+void
+Fader::resume()
+{
+	m_paused = false;
+}
+
 bool XineEngine::metaDataForUrl(const KURL &url, Engine::SimpleMetaBundle &b)
 {
     bool result = false;
--- trunk/extragear/multimedia/amarok/src/engine/xine/xine-engine.h #586430:586431
@@ -105,12 +105,15 @@
     xine_audio_port_t  *m_port;
     xine_post_t        *m_post;
     uint               m_fadeLength;
+    bool               m_paused;
 
     virtual void run();
 
 public:
     Fader( XineEngine *, uint fadeLengthMs );
    ~Fader();
+   void pause();
+   void resume();
 };
 
 class OutFader : public QObject, public QThread