Refactor PortAudio backend (#7444)

Refactors the PortAudio backend to fix issues with DirectSound and MME crackling and not loading properly, as well as to improve code quality and maintainability.

---------

Co-authored-by: Dalton Messmer <[email protected]>

Author: sakertooth

include/AudioDevice.h

@@ -113,6 +113,11 @@ class AudioDevice
 		m_sampleRate = _new_sr;
 	}
 
+	void setChannels(const ch_cnt_t channels)
+	{
+		m_channels = channels;
+	}
+
 	AudioEngine* audioEngine()
 	{
 		return m_audioEngine;

include/AudioPortAudio.h

@@ -25,136 +25,91 @@
 #ifndef LMMS_AUDIO_PORTAUDIO_H
 #define LMMS_AUDIO_PORTAUDIO_H
 
-#include <QObject>
-
 #include "lmmsconfig.h"
-#include "ComboBoxModel.h"
 
 #ifdef LMMS_HAVE_PORTAUDIO
 
-#   include <portaudio.h>
-
-#   include "AudioDevice.h"
-#   include "AudioDeviceSetupWidget.h"
-
-#   if defined paNeverDropInput || defined paNonInterleaved
-#	    define PORTAUDIO_V19
-#   else
-#	    define PORTAUDIO_V18
-#   endif
+#include <QComboBox>
+#include <QFormLayout>
+#include <QString>
+#include <QWidget>
+#include <portaudio.h>
 
-#endif
+#include "AudioDevice.h"
+#include "AudioDeviceSetupWidget.h"
 
+namespace lmms {
 
-namespace lmms
+namespace detail {
+class PortAudioInitializationGuard
 {
-
-class AudioPortAudioSetupUtil : public QObject
-{
-Q_OBJECT
-public slots:
-	void updateBackends();
-	void updateDevices();
-	void updateChannels();
-
 public:
-	ComboBoxModel m_backendModel;
-	ComboBoxModel m_deviceModel;
-};
-
-
-#ifdef LMMS_HAVE_PORTAUDIO
+	PortAudioInitializationGuard()
+		: m_error(Pa_Initialize())
+	{
+		if (m_error != paNoError) { throw std::runtime_error{"PortAudio: could not initialize"}; }
+	}
 
+	~PortAudioInitializationGuard()
+	{
+		if (m_error == paNoError) { Pa_Terminate(); }
+	}
 
-namespace gui
-{
-class ComboBox;
-}
+	PortAudioInitializationGuard(const PortAudioInitializationGuard&) = delete;
+	PortAudioInitializationGuard(PortAudioInitializationGuard&&) = delete;
+	PortAudioInitializationGuard& operator=(const PortAudioInitializationGuard&) = delete;
+	PortAudioInitializationGuard& operator=(PortAudioInitializationGuard&&) = delete;
 
+private:
+	PaError m_error = paNoError;
+};
+} // namespace detail
 
 class AudioPortAudio : public AudioDevice
 {
 public:
-	AudioPortAudio( bool & _success_ful, AudioEngine* audioEngine );
+	AudioPortAudio(bool& successful, AudioEngine* engine);
 	~AudioPortAudio() override;
 
-	inline static QString name()
-	{
-		return QT_TRANSLATE_NOOP( "AudioDeviceSetupWidget", "PortAudio" );
-	}
-
-	int process_callback(const float* _inputBuffer, float* _outputBuffer, f_cnt_t _framesPerBuffer);
-
-	class setupWidget : public gui::AudioDeviceSetupWidget
-	{
-	public:
-		setupWidget( QWidget * _parent );
-		~setupWidget() override;
-
-		void saveSettings() override;
-		void show() override;
-
-	private:
-		gui::ComboBox * m_backend;
-		gui::ComboBox * m_device;
-		AudioPortAudioSetupUtil m_setupUtil;
+	AudioPortAudio(const AudioPortAudio&) = delete;
+	AudioPortAudio(AudioPortAudio&&) = delete;
+	AudioPortAudio& operator=(const AudioPortAudio&) = delete;
+	AudioPortAudio& operator=(AudioPortAudio&&) = delete;
 
-	} ;
-
-private:
 	void startProcessing() override;
 	void stopProcessing() override;
 
-#ifdef PORTAUDIO_V19
-	static int _process_callback( const void *_inputBuffer, void * _outputBuffer,
-		unsigned long _framesPerBuffer,
-		const PaStreamCallbackTimeInfo * _timeInfo,
-		PaStreamCallbackFlags _statusFlags,
-		void *arg );
-
-#else
+	static auto name() -> QString { return QT_TRANSLATE_NOOP("AudioDeviceSetupWidget", "PortAudio"); }
 
-#define paContinue 0
-#define paComplete 1
-#define Pa_GetDeviceCount Pa_CountDevices
-#define Pa_GetDefaultInputDevice Pa_GetDefaultInputDeviceID
-#define Pa_GetDefaultOutputDevice Pa_GetDefaultOutputDeviceID
-#define Pa_IsStreamActive Pa_StreamActive
-
-	static int _process_callback( void * _inputBuffer, void * _outputBuffer,
-		unsigned long _framesPerBuffer, PaTimestamp _outTime, void * _arg );
-
-
-	using PaTime = double;
-	using PaDeviceIndex = PaDeviceID;
-
-	using PaStreamParameters = struct
-	{
-		PaDeviceIndex device;
-		int channelCount;
-		PaSampleFormat sampleFormat;
-		PaTime suggestedLatency;
-		void *hostApiSpecificStreamInfo;
-
-	} PaStreamParameters;
-#endif // PORTAUDIO_V19
+private:
+	static int processCallback(const void* input, void* output, unsigned long frameCount,
+		const PaStreamCallbackTimeInfo* timeInfo, PaStreamCallbackFlags statusFlags, void* userData);
 
-	PaStream * m_paStream;
-	PaStreamParameters m_outputParameters;
-	PaStreamParameters m_inputParameters;
+	detail::PortAudioInitializationGuard m_initGuard;
 
-	bool m_wasPAInitError;
+	PaStream* m_paStream = nullptr;
+	std::vector<SampleFrame> m_outBuf;
+	std::size_t m_outBufPos = 0;
+};
+} // namespace lmms
 
-	SampleFrame* m_outBuf;
-	std::size_t m_outBufPos;
-	fpp_t m_outBufSize;
+namespace lmms::gui {
+class AudioPortAudioSetupWidget : public AudioDeviceSetupWidget
+{
+public:
+	AudioPortAudioSetupWidget(QWidget* parent);
 
-	bool m_stopped;
+	void show() override;
+	void saveSettings() override;
 
-} ;
+private:
+	class DeviceSelectorWidget;
+	QComboBox* m_backendComboBox = nullptr;
+	DeviceSelectorWidget* m_inputDevice = nullptr;
+	DeviceSelectorWidget* m_outputDevice = nullptr;
+};
+} // namespace lmms::gui
 
 #endif // LMMS_HAVE_PORTAUDIO
 
-} // namespace lmms
-
 #endif // LMMS_AUDIO_PORTAUDIO_H

src/core/AudioEngine.cpp

@@ -23,6 +23,7 @@
  */
 
 #include "AudioEngine.h"
+#include <iostream>
 
 #include "MixHelpers.h"
 #include "denormals.h"
@@ -878,7 +879,7 @@ AudioDevice * AudioEngine::tryAudioDevices()
 
 
 #ifdef LMMS_HAVE_PORTAUDIO
-	if( dev_name == AudioPortAudio::name() || dev_name == "" )
+	if (dev_name == AudioPortAudio::name() || dev_name.isEmpty())
 	{
 		dev = new AudioPortAudio( success_ful, this );
 		if( success_ful )