Refactored code to insert the Downmix filter in processing thread.

etc/Translation/LameXP_DE.ts

@@ -1620,7 +1620,7 @@
     </message>
     <message>
         <source>Enforce Stereo Downmix of Surround (Multi-Channel) Sources</source>
-        <translation>Surround (Mehrkanal-Ton) Quellen auf Stereo heruntermischen</translation>
+        <translation>Surround (Mehrkanal-Ton) Quellen immer auf Stereo heruntermischen</translation>
     </message>
 </context>
 <context>

src/Config.h

@@ -30,7 +30,7 @@
 #define VER_LAMEXP_MINOR_LO					3
 #define VER_LAMEXP_TYPE						Alpha
 #define VER_LAMEXP_PATCH					8
-#define VER_LAMEXP_BUILD					623
+#define VER_LAMEXP_BUILD					624
 
 ///////////////////////////////////////////////////////////////////////////////
 // Tools versions

src/Dialog_Processing.cpp

@@ -649,7 +649,7 @@ void ProcessingDialog::startNextJob(void)
 	);
 
 	//Add audio filters
-	if(m_settings->forceStereoDownmix() && (!encoder->requiresDownmix()) && ((currentFile.formatAudioChannels() > 2) || (currentFile.formatAudioChannels() == 0)))
+	if(m_settings->forceStereoDownmix() && ((currentFile.formatAudioChannels() > 2) || (currentFile.formatAudioChannels() == 0)))
 	{
 		thread->addFilter(new DownmixFilter());
 	}

src/Thread_Process.cpp

@@ -135,9 +135,9 @@ void ProcessThread::processFile()
 	}
 
 	//Do we need Stereo downmix?
-	if(((m_audioFile.formatAudioChannels() > 2) || (m_audioFile.formatAudioChannels() == 0)) && m_encoder->requiresDownmix())
+	if(m_encoder->requiresDownmix() && ((m_audioFile.formatAudioChannels() > 2) || (m_audioFile.formatAudioChannels() == 0)))
 	{
-		m_filters.prepend(new DownmixFilter());
+		insertDownmixFilter();
 	}
 
 	QString sourceFile = m_audioFile.filePath();
@@ -391,6 +391,27 @@ void ProcessThread::insertDownsampleFilter(void)
 	}
 }
 
+void ProcessThread::insertDownmixFilter(void)
+{
+	bool applyDownmixing = true;
+		
+	//Check if downmixing filter is already in the chain
+	for(int i = 0; i < m_filters.count(); i++)
+	{
+		if(dynamic_cast<DownmixFilter*>(m_filters.at(i)))
+		{
+			qWarning("Encoder requires Stereo downmix, but user has already forced downmix!");
+			applyDownmixing = false;
+		}
+	}
+		
+	//Now add the downmixing filter, if needed
+	if(applyDownmixing)
+	{
+		m_filters.prepend(new DownmixFilter());
+	}
+}
+
 ////////////////////////////////////////////////////////////
 // PUBLIC FUNCTIONS
 ////////////////////////////////////////////////////////////

src/Thread_Process.h

@@ -69,6 +69,7 @@ private:
 	QString generateOutFileName(void);
 	QString generateTempFileName(void);
 	void insertDownsampleFilter(void);
+	void insertDownmixFilter(void);
 	
 	const QUuid m_jobId;
 	AudioFileModel m_audioFile;