Fix access to CPrologEpilogVideo after destruction from sound callback

client/CMusicHandler.cpp

@@ -322,6 +322,13 @@ void CSoundHandler::setCallback(int channel, std::function<void()> function)
 		iter->second.push_back(function);
 }
 
+void CSoundHandler::resetCallback(int channel)
+{
+	boost::mutex::scoped_lock lockGuard(mutexCallbacks);
+
+	callbacks.erase(channel);
+}
+
 void CSoundHandler::soundFinishedCallback(int channel)
 {
 	boost::mutex::scoped_lock lockGuard(mutexCallbacks);

client/CMusicHandler.h

@@ -85,6 +85,7 @@ public:
 	void stopSound(int handler);
 
 	void setCallback(int channel, std::function<void()> function);
+	void resetCallback(int channel);
 	void soundFinishedCallback(int channel);
 
 	int ambientGetRange() const;

client/mainmenu/CPrologEpilogVideo.cpp

@@ -74,6 +74,7 @@ void CPrologEpilogVideo::show(Canvas & to)
 void CPrologEpilogVideo::clickPressed(const Point & cursorPosition)
 {
 	close();
+	CCS->soundh->resetCallback(voiceSoundHandle); // reset callback to avoid memory corruption since 'this' will be destroyed
 	CCS->soundh->stopSound(voiceSoundHandle);
 	CCS->soundh->stopSound(videoSoundHandle);
 	if(exitCb)