Version 0.9

Added: Filter type "IIR", which allows to specify a user-defined IIR filter of arbitrary order with custom coefficients.
Improved: For playback devices, the APO is now installed both as GFX (post-mix) and LFX (pre-mix) APO. Normally the filtering happens in GFX, but the command "Stage" allows to select LFX to apply effects based on the number of input channels.
Added: Expression language. The commands "If", "ElseIf", "Else", "EndIf", "Eval" and inline expressions allow to change the filter behaviour based on runtime conditions.
Added: Command "Copy", which copies audio data between channels.
Added: Command "Delay", which delays the audio on the currently selected channels.
Improved: Configuration files are now locked exclusively for writing while reading them.
Improved: There is now a transition (10 ms) from old to new configuration after loading.
Improved: Substantial internal restructuring to improve extensibility and maintainability. Filtering commands now work exactly in the order they were specified.
Fixed: When the microphone input was in stereo but the application requested a mono stream, the audio was heavily distorted.
Fixed: The sine sweep generated by the Benchmark application had floating-point precision issues leading to severe artifacts when certain filters were applied.

DeviceAPOInfo.h

@@ -39,13 +39,15 @@ public:
 	std::wstring deviceName;
 	std::wstring connectionName;
 	std::wstring deviceGuid;
-	std::wstring originalApoGuid;
+	std::wstring originalLfxGuid;
+	std::wstring originalGfxGuid;
 	bool isInput;
 	bool isInstalled;
 	bool isLFX;
 	bool isAPO2;
-	bool foundAPO2Values;
+	bool isDual;
+	bool installAsAPO2;
 
 private:
-	bool tryAPOGuid(const std::wstring& keyPath, const wchar_t* valueName, bool lfx, bool apo2);
+	bool tryAPOGuid(const std::wstring& keyPath, const std::wstring& valueName, GUID guid, bool lfx, bool apo2);
 };