Reworked routing of MIDI streams and audio rendering

- Audio drivers now use SynthRoute objects and not QSynth directly. - MIDI drivers now supply a reference to the relevant MidiSession when pushing / playing MIDI messages thus making the MIDI stream identifiable. - SynthRoute now implements merging of multiple MIDI streams immediately before audio rendering pass, so that the resulting stream contains MIDI messages ordered by their timestamp frame-wise. This improves the timing accuracy in case more than one MIDI stream is connected to a SynthRoute.
2026-07-08 18:16:13 +00:00 · 2020-09-04 20:01:33 +03:00
parent 2ffcea8556
commit ab3ea4ed07
34 changed files with 325 additions and 198 deletions
--- a/mt32emu_qt/src/AudioFileWriter.cpp
+++ b/mt32emu_qt/src/AudioFileWriter.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -120,15 +120,16 @@ void AudioFileWriter::close() {
 	file.close();
 }

-AudioFileRenderer::AudioFileRenderer() : synth(NULL), buffer(NULL), parsers(NULL) {
+AudioFileRenderer::AudioFileRenderer() : buffer(NULL), parsers(NULL) {
+	audioRenderer.synth = NULL;
 	connect(this, SIGNAL(parsingFailed(const QString &, const QString &)), Master::getInstance(), SLOT(showBalloon(const QString &, const QString &)));
 }

 AudioFileRenderer::~AudioFileRenderer() {
 	stop();
-	if (!realtimeMode && synth != NULL) {
-		synth->close();
-		delete synth;
+	if (!realtimeMode && audioRenderer.synth != NULL) {
+		audioRenderer.synth->close();
+		delete audioRenderer.synth;
 	}
 	delete[] parsers;
 	delete[] buffer;
@@ -153,23 +154,23 @@ bool AudioFileRenderer::convertMIDIFiles(QString useOutFileName, QStringList mid
 		}
 	}
 	parsers[parsersCount - 1].addChannelsReset();
-	if (synth != NULL) {
-		synth->close();
-		delete synth;
+	if (audioRenderer.synth != NULL) {
+		audioRenderer.synth->close();
+		delete audioRenderer.synth;
 	}
-	synth = new QSynth(this);
+	audioRenderer.synth = new QSynth(this);
 	sampleRate = 0;
-	if (!synth->open(sampleRate, MT32Emu::SamplerateConversionQuality_BEST, synthProfileName)) {
-		synth->close();
-		delete synth;
-		synth = NULL;
+	if (!audioRenderer.synth->open(sampleRate, MT32Emu::SamplerateConversionQuality_BEST, synthProfileName)) {
+		audioRenderer.synth->close();
+		delete audioRenderer.synth;
+		audioRenderer.synth = NULL;
 		delete[] parsers;
 		parsers = NULL;
 		qDebug() << "AudioFileRenderer: Can't open synth";
 		QMessageBox::critical(NULL, "Error", "Failed to open synth");
 		return false;
 	}
-	Master::getInstance()->setAudioFileWriterSynth(synth);
+	Master::getInstance()->setAudioFileWriterSynth(audioRenderer.synth);
 	bufferSize = useBufferSize;
 	outFileName = useOutFileName;
 	realtimeMode = false;
@@ -180,9 +181,9 @@ bool AudioFileRenderer::convertMIDIFiles(QString useOutFileName, QStringList mid
 	return true;
 }

-void AudioFileRenderer::startRealtimeProcessing(QSynth *useSynth, unsigned int useSampleRate, QString useOutFileName, unsigned int useBufferSize) {
+void AudioFileRenderer::startRealtimeProcessing(SynthRoute *useSynthRoute, unsigned int useSampleRate, QString useOutFileName, unsigned int useBufferSize) {
 	if (useOutFileName.isEmpty()) return;
-	synth = useSynth;
+	audioRenderer.synthRoute = useSynthRoute;
 	sampleRate = useSampleRate;
 	bufferSize = useBufferSize;
 	outFileName = useOutFileName;
@@ -198,10 +199,25 @@ void AudioFileRenderer::stop() {
 	wait();
 }

+inline void AudioFileRenderer::closeAudioRenderer() {
+	if (realtimeMode) {
+		audioRenderer.synthRoute->audioStreamFailed();
+	} else {
+		audioRenderer.synth->close();
+	}
+}
+
+inline void AudioFileRenderer::render(qint16 *buffer, uint length) {
+	if (realtimeMode) {
+		audioRenderer.synthRoute->render(buffer, length);
+	} else {
+		audioRenderer.synth->render(buffer, length);
+	}
+}
 void AudioFileRenderer::run() {
 	AudioFileWriter writer(sampleRate, outFileName);
 	if (!writer.open(!realtimeMode)) {
-		synth->close();
+		closeAudioRenderer();
 		if (!realtimeMode) Master::getInstance()->setAudioFileWriterSynth(NULL);
 		emit conversionFinished();
 		return;
@@ -243,10 +259,10 @@ void AudioFileRenderer::run() {
 				}
 				switch (e.getType()) {
 					case SHORT_MESSAGE:
-						eventPushed = synth->playMIDIShortMessage(e.getShortMessage(), nextEventFrames);
+						eventPushed = audioRenderer.synth->playMIDIShortMessage(e.getShortMessage(), nextEventFrames);
 						break;
 					case SYSEX:
-						eventPushed = synth->playMIDISysex(e.getSysexData(), e.getSysexLen(), nextEventFrames);
+						eventPushed = audioRenderer.synth->playMIDISysex(e.getSysexData(), e.getSysexLen(), nextEventFrames);
 						break;
 					case SET_TEMPO:
 						midiTick = parsers[parserIx].getMidiTick(e.getShortMessage());
@@ -270,16 +286,16 @@ void AudioFileRenderer::run() {
 					midiTick = parsers[parserIx].getMidiTick();
 					continue;
 				}
-				if (!synth->isActive() && frameCount == 0) break;
+				if (!audioRenderer.synth->isActive() && frameCount == 0) break;
 				frameCount += bufferSize;
 				qDebug() << "AudioFileRenderer: Rendering after the end of MIDI file, time:" << (double)midiNanos / MasterClock::NANOS_PER_SECOND;
 			}
 		}
 		while (frameCount > 0) {
 			uint framesToRender = qMin(bufferSize, frameCount);
-			synth->render(buffer, framesToRender);
+			render(buffer, framesToRender);
 			if (!writer.write(buffer, framesToRender)) {
-				synth->close();
+				closeAudioRenderer();
 				if (!realtimeMode) Master::getInstance()->setAudioFileWriterSynth(NULL);
 				emit conversionFinished();
 				return;
@@ -292,7 +308,7 @@ void AudioFileRenderer::run() {
 	qDebug() << "AudioFileRenderer: Rendering finished";
 	if (!realtimeMode) qDebug() << "AudioFileRenderer: Elapsed seconds: " << 1e-9 * (MasterClock::getClockNanos() - startNanos);
 	writer.close();
-	synth->close();
+	closeAudioRenderer();
 	if (!realtimeMode) Master::getInstance()->setAudioFileWriterSynth(NULL);
 	if (!stopProcessing) emit conversionFinished();
 }
--- a/mt32emu_qt/src/AudioFileWriter.h
+++ b/mt32emu_qt/src/AudioFileWriter.h
@@ -24,6 +24,7 @@ private:

 class MidiParser;
 class QSynth;
+class SynthRoute;

 class AudioFileRenderer : public QThread {
 	Q_OBJECT
@@ -33,14 +34,14 @@ public:
 	~AudioFileRenderer();

 	bool convertMIDIFiles(QString useOutFileName, QStringList useMIDIFileNameList, QString synthProfileName, quint32 bufferSize = 65536);
-	void startRealtimeProcessing(QSynth *useSynth, quint32 useSampleRate, QString useOutFileName, quint32 bufferSize);
+	void startRealtimeProcessing(SynthRoute *synthRoute, quint32 useSampleRate, QString useOutFileName, quint32 bufferSize);
 	void stop();

-protected:
-	void run();
-
 private:
-	QSynth *synth;
+	union {
+		QSynth *synth;
+		SynthRoute *synthRoute;
+	} audioRenderer;
 	uint sampleRate;
 	QString outFileName;
 	unsigned int bufferSize;
@@ -50,6 +51,10 @@ private:
 	bool realtimeMode;
 	volatile bool stopProcessing;

+	inline void closeAudioRenderer();
+	inline void render(qint16 *buffer, uint length);
+	void run();
+
 signals:
 	void parsingFailed(const QString &, const QString &);
 	void midiEventProcessed(int midiEventsProcessed, int midiEventsTotal);
--- a/mt32emu_qt/src/MidiSession.cpp
+++ b/mt32emu_qt/src/MidiSession.cpp
@@ -20,16 +20,18 @@
 using namespace MT32Emu;

 MidiSession::MidiSession(QObject *parent, MidiDriver *useMidiDriver, QString useName, SynthRoute *useSynthRoute) :
-	QObject(parent), midiDriver(useMidiDriver), name(useName), synthRoute(useSynthRoute), qMidiStreamParser(NULL)
+	QObject(parent), midiDriver(useMidiDriver), name(useName), synthRoute(useSynthRoute),
+	qMidiStreamParser(), qMidiBuffer()
 {}

 MidiSession::~MidiSession() {
-	if (qMidiStreamParser != NULL) delete qMidiStreamParser;
+	delete qMidiStreamParser;
+	delete qMidiBuffer;
 }

 QMidiStreamParser *MidiSession::getQMidiStreamParser() {
 	if (qMidiStreamParser == NULL) {
-		qMidiStreamParser = new QMidiStreamParser(*synthRoute);
+		qMidiStreamParser = new QMidiStreamParser(*this);
 	}
 	return qMidiStreamParser;
 }
@@ -41,7 +43,7 @@ QMidiBuffer *MidiSession::getQMidiBuffer() {
 	return qMidiBuffer;
 }

-SynthRoute *MidiSession::getSynthRoute() {
+SynthRoute *MidiSession::getSynthRoute() const {
 	return synthRoute;
 }

@@ -53,18 +55,18 @@ void MidiSession::setName(const QString &newName) {
 	name = newName;
 }

-QMidiStreamParser::QMidiStreamParser(SynthRoute &useSynthRoute) : synthRoute(useSynthRoute) {}
+QMidiStreamParser::QMidiStreamParser(MidiSession &useMidiSession) : midiSession(useMidiSession) {}

 void QMidiStreamParser::setTimestamp(MasterClockNanos newTimestamp) {
 	timestamp = newTimestamp;
 }

 void QMidiStreamParser::handleShortMessage(const Bit32u message) {
-	synthRoute.pushMIDIShortMessage(message, timestamp);
+	midiSession.getSynthRoute()->pushMIDIShortMessage(midiSession, message, timestamp);
 }

 void QMidiStreamParser::handleSysex(const Bit8u stream[], const Bit32u length) {
-	synthRoute.pushMIDISysex(stream, length, timestamp);
+	midiSession.getSynthRoute()->pushMIDISysex(midiSession, stream, length, timestamp);
 }

 void QMidiStreamParser::handleSystemRealtimeMessage(const Bit8u realtime) {
--- a/mt32emu_qt/src/MidiSession.h
+++ b/mt32emu_qt/src/MidiSession.h
@@ -25,14 +25,14 @@ private:
 public:
 	QString getName();
 	void setName(const QString &newName);
-	SynthRoute *getSynthRoute();
+	SynthRoute *getSynthRoute() const;
 	QMidiStreamParser *getQMidiStreamParser();
 	QMidiBuffer *getQMidiBuffer();
 };

 class QMidiStreamParser : public MT32Emu::MidiStreamParser {
 public:
-	QMidiStreamParser(SynthRoute &useSynthRoute);
+	QMidiStreamParser(MidiSession &midiSession);
 	void setTimestamp(MasterClockNanos newTimestamp);

 protected:
@@ -42,7 +42,7 @@ protected:
 	void printDebug(const char *debugMessage);

 private:
-	SynthRoute &synthRoute;
+	MidiSession &midiSession;
 	MasterClockNanos timestamp;
 };

--- a/mt32emu_qt/src/QSynth.cpp
+++ b/mt32emu_qt/src/QSynth.cpp
@@ -955,7 +955,7 @@ bool QSynth::isRealtime() const {
 	return realtimeHelper != NULL;
 }

-void QSynth::setRealtime() {
+void QSynth::enableRealtime() {
 	QMutexLocker synthLocker(synthMutex);
 	synth->preallocateReverbMemory(true);
 	synth->configureMIDIEventQueueSysexStorage(MAX_STREAM_BUFFER_SIZE);
--- a/mt32emu_qt/src/QSynth.h
+++ b/mt32emu_qt/src/QSynth.h
@@ -131,7 +131,7 @@ public:
 	void close();
 	void reset() const;
 	bool isRealtime() const;
-	void setRealtime();
+	void enableRealtime();

 	void flushMIDIQueue() const;
 	void playMIDIShortMessageNow(MT32Emu::Bit32u msg) const;
--- a/mt32emu_qt/src/SynthRoute.cpp
+++ b/mt32emu_qt/src/SynthRoute.cpp
@@ -26,6 +26,7 @@

 #include "SynthRoute.h"
 #include "MidiSession.h"
+#include "QMidiBuffer.h"
 #include "audiodrv/AudioDriver.h"

 using namespace MT32Emu;
@@ -35,6 +36,7 @@ SynthRoute::SynthRoute(QObject *parent) :
 	state(SynthRouteState_CLOSED),
 	qSynth(this),
 	exclusiveMidiMode(),
+	multiMidiMode(),
 	audioDevice(NULL),
 	audioStream(NULL),
 	debugLastEventTimestamp(0)
@@ -80,9 +82,9 @@ bool SynthRoute::open(AudioStreamFactory audioStreamFactory) {
 			qDebug() << "Using sample rate:" << sampleRate;

 			if (exclusiveMidiMode && audioStreamFactory != NULL) {
-				audioStream = audioStreamFactory(audioDevice, qSynth, sampleRate, midiSessions.first());
+				audioStream = audioStreamFactory(audioDevice, *this, sampleRate, midiSessions.first());
 			} else {
-				audioStream = audioDevice->startAudioStream(qSynth, sampleRate);
+				audioStream = audioDevice->startAudioStream(*this, sampleRate);
 			}
 			if (audioStream != NULL) {
 				setState(SynthRouteState_OPEN);
@@ -123,6 +125,7 @@ bool SynthRoute::enableExclusiveMidiMode(MidiSession *midiSession) {
 	if (exclusiveMidiMode || hasMIDISessions()) return false;
 	addMidiSession(midiSession);
 	exclusiveMidiMode = true;
+	qDebug() << "SynthRoute: exclusiveMidiMode enabled";
 	return true;
 }

@@ -131,6 +134,7 @@ void SynthRoute::disableExclusiveMidiMode() {
 		MidiSession *midiSession = midiSessions.first();
 		removeMidiSession(midiSession);
 		exclusiveMidiMode = false;
+		qDebug() << "SynthRoute: exclusiveMidiMode disabled";
 		emit exclusiveMidiSessionRemoved(midiSession);
 	}
 }
@@ -139,19 +143,32 @@ bool SynthRoute::isExclusiveMidiModeEnabled() {
 	return exclusiveMidiMode;
 }

+void SynthRoute::enableMultiMidiMode() {
+	if (exclusiveMidiMode || multiMidiMode) return;
+	multiMidiMode = true;
+	qDebug() << "SynthRoute: started merging MIDI stream buffers";
+}
+
 SynthRouteState SynthRoute::getState() const {
 	return state;
 }

 void SynthRoute::addMidiSession(MidiSession *midiSession) {
 	if (exclusiveMidiMode) return;
+	if (hasMIDISessions() && !multiMidiMode) enableMultiMidiMode();
+	QMutexLocker midiSessionsLocker(&midiSessionsMutex);
 	midiSessions.append(midiSession);
 	emit midiSessionAdded(midiSession);
 }

 void SynthRoute::removeMidiSession(MidiSession *midiSession) {
+	QMutexLocker midiSessionsLocker(&midiSessionsMutex);
 	midiSessions.removeOne(midiSession);
 	emit midiSessionRemoved(midiSession);
+	if (!hasMIDISessions() && multiMidiMode) {
+		multiMidiMode = false;
+		qDebug() << "SynthRoute: stopped merging MIDI stream buffers";
+	}
 }

 void SynthRoute::setMidiSessionName(MidiSession *midiSession, QString name) {
@@ -200,7 +217,7 @@ bool SynthRoute::connectReportHandler(const char *signal, const QObject *receive
 	return QObject::connect(qSynth.getReportHandler(), signal, receiver, slot);
 }

-bool SynthRoute::pushMIDIShortMessage(Bit32u msg, MasterClockNanos refNanos) {
+bool SynthRoute::pushMIDIShortMessage(MidiSession &midiSession, Bit32u msg, MasterClockNanos refNanos) {
 	recorder.recordShortMessage(msg, refNanos);
 	AudioStream *stream = audioStream;
 	if (stream == NULL) return false;
@@ -215,19 +232,102 @@ bool SynthRoute::pushMIDIShortMessage(Bit32u msg, MasterClockNanos refNanos) {
 		debugLastEventTimestamp = timestamp;
 		return false;
 	}
-	return qSynth.playMIDIShortMessage(msg, timestamp);
+	return playMIDIShortMessage(midiSession, msg, timestamp);
 }

-bool SynthRoute::pushMIDISysex(const Bit8u *sysexData, unsigned int sysexLen, MasterClockNanos refNanos) {
+bool SynthRoute::pushMIDISysex(MidiSession &midiSession, const Bit8u *sysexData, unsigned int sysexLen, MasterClockNanos refNanos) {
 	recorder.recordSysex(sysexData, sysexLen, refNanos);
 	AudioStream *stream = audioStream;
 	if (stream == NULL) return false;
 	quint64 timestamp = stream->estimateMIDITimestamp(refNanos);
-	return qSynth.playMIDISysex(sysexData, sysexLen, timestamp);
+	return playMIDISysex(midiSession, sysexData, sysexLen, timestamp);
+}
+
+bool SynthRoute::playMIDIShortMessage(MidiSession &midiSession, Bit32u msg, quint64 timestamp) {
+	if (multiMidiMode) {
+		QMidiBuffer *qMidiBuffer = midiSession.getQMidiBuffer();
+		if (qMidiBuffer->pushShortMessage(timestamp, msg)) {
+			qMidiBuffer->flush();
+			return true;
+		}
+		return false;
+	} else {
+		return qSynth.playMIDIShortMessage(msg, timestamp);
+	}
+}
+
+bool SynthRoute::playMIDISysex(MidiSession &midiSession, const Bit8u *sysex, Bit32u sysexLen, quint64 timestamp) {
+	if (multiMidiMode) {
+		QMidiBuffer *qMidiBuffer = midiSession.getQMidiBuffer();
+		if (qMidiBuffer->pushSysexMessage(timestamp, sysexLen, sysex)) {
+			qMidiBuffer->flush();
+			return true;
+		}
+		return false;
+	} else {
+		return qSynth.playMIDISysex(sysex, sysexLen, timestamp);
+	}
+}
+
+void SynthRoute::mergeMidiStreams(uint renderingPassFrameLength) {
+	QMutexLocker midiSessionsLocker(&midiSessionsMutex);
+	QVarLengthArray<QMidiBuffer *, 16> streamBuffers;
+	const quint64 renderingPassEndTimestamp = audioStream->computeMIDITimestamp(renderingPassFrameLength);
+
+	for (int i = 0; i < midiSessions.size(); i++) {
+		QMidiBuffer *midiBuffer = midiSessions.at(i)->getQMidiBuffer();
+		if (midiBuffer->retieveEvents() && midiBuffer->getEventTimestamp() < renderingPassEndTimestamp) {
+			streamBuffers.append(midiBuffer);
+		}
+	}
+
+	while (!streamBuffers.isEmpty()) {
+		int nextEventBufferIx = 0;
+		quint64 nextEventTimestamp = streamBuffers.at(nextEventBufferIx)->getEventTimestamp();
+		for (int i = 1; i < streamBuffers.size(); i++) {
+			quint64 eventTimestamp = streamBuffers.at(i)->getEventTimestamp();
+			if (eventTimestamp < nextEventTimestamp) {
+				nextEventBufferIx = i;
+				nextEventTimestamp = eventTimestamp;
+			}
+		}
+		QMidiBuffer *midiBuffer = streamBuffers.at(nextEventBufferIx);
+		do {
+			const uchar *sysexData;
+			quint32 eventData = midiBuffer->getEventData(sysexData);
+			if (sysexData == NULL) {
+				qSynth.playMIDIShortMessage(eventData, nextEventTimestamp);
+			} else {
+				qSynth.playMIDISysex(sysexData, eventData, nextEventTimestamp);
+			}
+			if (!(midiBuffer->nextEvent() && midiBuffer->getEventTimestamp() < renderingPassEndTimestamp)) {
+				streamBuffers.remove(nextEventBufferIx);
+				break;
+			}
+		} while (midiBuffer->getEventTimestamp() == nextEventTimestamp);
+	}
+}
+
+void SynthRoute::render(MT32Emu::Bit16s *buffer, uint length) {
+	if (multiMidiMode) mergeMidiStreams(length);
+	qSynth.render(buffer, length);
+}
+
+void SynthRoute::render(float *buffer, uint length) {
+	if (multiMidiMode) mergeMidiStreams(length);
+	qSynth.render(buffer, length);
+}
+
+void SynthRoute::audioStreamFailed() {
+	qSynth.close();
 }

 // QSynth delegation

+void SynthRoute::enableRealtimeMode() {
+	qSynth.enableRealtime();
+}
+
 void SynthRoute::flushMIDIQueue() {
 	qSynth.flushMIDIQueue();
 }
@@ -240,14 +340,6 @@ void SynthRoute::playMIDISysexNow(const Bit8u *sysex, Bit32u sysexLen) {
 	qSynth.playMIDISysexNow(sysex, sysexLen);
 }

-bool SynthRoute::playMIDIShortMessage(Bit32u msg, quint64 timestamp) {
-	return qSynth.playMIDIShortMessage(msg, timestamp);
-}
-
-bool SynthRoute::playMIDISysex(const Bit8u *sysex, Bit32u sysexLen, quint64 timestamp) {
-	return qSynth.playMIDISysex(sysex, sysexLen, timestamp);
-}
-
 void SynthRoute::reset() {
 	qSynth.reset();
 }
--- a/mt32emu_qt/src/SynthRoute.h
+++ b/mt32emu_qt/src/SynthRoute.h
@@ -23,13 +23,15 @@ enum SynthRouteState {
 class SynthRoute : public QObject {
 	Q_OBJECT
 private:
-	typedef AudioStream *(*AudioStreamFactory)(const AudioDevice *, QSynth &, const uint, MidiSession *midiSession);
+	typedef AudioStream *(*AudioStreamFactory)(const AudioDevice *, SynthRoute &, const uint, MidiSession *midiSession);

 	SynthRouteState state;
 	QSynth qSynth;
 	QList<MidiSession *> midiSessions;
+	QMutex midiSessionsMutex;
 	MidiRecorder recorder;
 	bool exclusiveMidiMode;
+	volatile bool multiMidiMode;

 	const AudioDevice *audioDevice;
 	AudioStream *audioStream; // NULL until a stream is created
@@ -48,6 +50,7 @@ public:
 	void reset();
 	bool enableExclusiveMidiMode(MidiSession *midiSession);
 	bool isExclusiveMidiModeEnabled();
+	void enableMultiMidiMode();

 	const QString getPatchName(int partNum) const;
 	void getPartStates(bool *partStates) const;
@@ -58,10 +61,16 @@ public:
 	void flushMIDIQueue();
 	void playMIDIShortMessageNow(MT32Emu::Bit32u msg);
 	void playMIDISysexNow(const MT32Emu::Bit8u *sysex, MT32Emu::Bit32u sysexLen);
-	bool playMIDIShortMessage(MT32Emu::Bit32u msg, quint64 timestamp);
-	bool playMIDISysex(const MT32Emu::Bit8u *sysex, MT32Emu::Bit32u sysexLen, quint64 timestamp);
-	bool pushMIDIShortMessage(MT32Emu::Bit32u msg, MasterClockNanos midiNanos);
-	bool pushMIDISysex(const MT32Emu::Bit8u *sysex, unsigned int sysexLen, MasterClockNanos midiNanos);
+	bool playMIDIShortMessage(MidiSession &midiSession, MT32Emu::Bit32u msg, quint64 timestamp);
+	bool playMIDISysex(MidiSession &midiSession, const MT32Emu::Bit8u *sysex, MT32Emu::Bit32u sysexLen, quint64 timestamp);
+	bool pushMIDIShortMessage(MidiSession &midiSession, MT32Emu::Bit32u msg, MasterClockNanos midiNanos);
+	bool pushMIDISysex(MidiSession &midiSession, const MT32Emu::Bit8u *sysex, unsigned int sysexLen, MasterClockNanos midiNanos);
+	void mergeMidiStreams(uint renderingPassFrameLength);
+	void render(MT32Emu::Bit16s *buffer, uint length);
+	void render(float *buffer, uint length);
+	void audioStreamFailed();
+
+	void enableRealtimeMode();
 	void setMasterVolume(int masterVolume);
 	void setOutputGain(float outputGain);
 	void setReverbOutputGain(float reverbOutputGain);
--- a/mt32emu_qt/src/audiodrv/AlsaAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/AlsaAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -29,7 +29,7 @@ static const unsigned int DEFAULT_AUDIO_LATENCY = 64;
 static const unsigned int DEFAULT_MIDI_LATENCY = 32;

 AlsaAudioStream::AlsaAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate), stream(NULL), processingThreadID(0), stopProcessing(false)
+  AudioStream(useSettings, useSynth, useSampleRate), stream(NULL), processingThreadID(0), stopProcessing(false)
 {
 	bufferSize = settings.chunkLen * sampleRate / MasterClock::MILLIS_PER_SECOND;
 	buffer = new Bit16s[/* channels */ 2 * bufferSize];
@@ -80,7 +80,7 @@ void *AlsaAudioStream::processingThread(void *userData) {
 	if (isErrorOccured) {
 		snd_pcm_close(audioStream.stream);
 		audioStream.stream = NULL;
-		audioStream.synth.close();
+		audioStream.synthRoute.audioStreamFailed();
 	} else {
 		audioStream.stopProcessing = false;
 	}
@@ -106,7 +106,7 @@ bool AlsaAudioStream::start(const char *deviceID) {

 	// Set Sample format to use
 	error = snd_pcm_set_params(stream, SND_PCM_FORMAT_S16, SND_PCM_ACCESS_RW_INTERLEAVED, /* channels */ 2,
-		sampleRate, /* allow resampling */ 1, settings.audioLatency * MasterClock::MICROS_PER_MILLISECOND);
+	  sampleRate, /* allow resampling */ 1, settings.audioLatency * MasterClock::MICROS_PER_MILLISECOND);
 	if (error < 0) {
 		qDebug() << "snd_pcm_set_params failed:" << snd_strerror(error);
 		snd_pcm_close(stream);
--- a/mt32emu_qt/src/audiodrv/AudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/AudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -18,8 +18,8 @@
 #include <QSettings>
 #include "../Master.h"

-AudioStream::AudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	synth(useSynth), sampleRate(useSampleRate), settings(useSettings), renderedFramesCount(0), lastEstimatedPlayedFramesCount(0), resetScheduled(true)
+AudioStream::AudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate) :
+	synthRoute(useSynthRoute), sampleRate(useSampleRate), settings(useSettings), renderedFramesCount(0), lastEstimatedPlayedFramesCount(0), resetScheduled(true)
 {
 	audioLatencyFrames = settings.audioLatency * sampleRate / MasterClock::MILLIS_PER_SECOND;
 	midiLatencyFrames = settings.midiLatency * sampleRate / MasterClock::MILLIS_PER_SECOND;
@@ -51,6 +51,10 @@ quint64 AudioStream::estimateMIDITimestamp(const MasterClockNanos refNanos) {
 	return timestamp;
 }

+quint64 AudioStream::computeMIDITimestamp(uint relativeFrameTime) const {
+	return renderedFramesCount + relativeFrameTime;
+}
+
 void AudioStream::updateTimeInfo(const MasterClockNanos measuredNanos, const quint32 framesInAudioBuffer) {
 #if 0
 	qDebug() << "R" << renderedFramesCount - timeInfo[timeInfoIx].lastPlayedFramesCount
--- a/mt32emu_qt/src/audiodrv/AudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/AudioDriver.h
@@ -11,12 +11,12 @@
 #include "../MasterClock.h"

 class AudioDriver;
-class QSynth;
+class SynthRoute;
 struct AudioDriverSettings;

 class AudioStream {
 protected:
-	QSynth &synth;
+	SynthRoute &synthRoute;
 	const quint32 sampleRate;
 	const AudioDriverSettings &settings;
 	quint32 audioLatencyFrames;
@@ -37,9 +37,10 @@ protected:
 	bool isAutoLatencyMode() const;

 public:
-	AudioStream(const AudioDriverSettings &settings, QSynth &synth, const quint32 sampleRate);
+	AudioStream(const AudioDriverSettings &settings, SynthRoute &synthRoute, const quint32 sampleRate);
 	virtual ~AudioStream() {}
 	virtual quint64 estimateMIDITimestamp(const MasterClockNanos refNanos = 0);
+	quint64 computeMIDITimestamp(uint relativeFrameTime) const;
 };

 class AudioDevice {
@@ -49,7 +50,7 @@ public:

 	AudioDevice(AudioDriver &driver, const QString name);
 	virtual ~AudioDevice() {}
-	virtual AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const = 0;
+	virtual AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const = 0;
 };

 Q_DECLARE_METATYPE(const AudioDevice *)
--- a/mt32emu_qt/src/audiodrv/AudioFileWriterDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/AudioFileWriterDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -23,8 +23,8 @@
 static const unsigned int DEFAULT_AUDIO_LATENCY = 150;
 static const unsigned int DEFAULT_MIDI_LATENCY = 200;

-AudioFileWriterStream::AudioFileWriterStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate) {}
+AudioFileWriterStream::AudioFileWriterStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate) {}

 bool AudioFileWriterStream::start() {
 	static QString currentDir = NULL;
@@ -32,7 +32,7 @@ bool AudioFileWriterStream::start() {
 	if (fileName.isEmpty()) return false;
 	currentDir = QDir(fileName).absolutePath();
 	timeInfo[0].lastPlayedNanos = MasterClock::getClockNanos();
-	writer.startRealtimeProcessing(&synth, sampleRate, fileName, audioLatencyFrames);
+	writer.startRealtimeProcessing(&synthRoute, sampleRate, fileName, audioLatencyFrames);
 	return true;
 }

@@ -48,8 +48,8 @@ quint64 AudioFileWriterStream::estimateMIDITimestamp(const MasterClockNanos refN
 AudioFileWriterDevice::AudioFileWriterDevice(AudioFileWriterDriver &driver, QString useDeviceName) :
 	AudioDevice(driver, useDeviceName) {}

-AudioStream *AudioFileWriterDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
-	AudioFileWriterStream *stream = new AudioFileWriterStream(driver.getAudioSettings(), synth, sampleRate);
+AudioStream *AudioFileWriterDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
+	AudioFileWriterStream *stream = new AudioFileWriterStream(driver.getAudioSettings(), synthRoute, sampleRate);
 	if (stream->start()) {
 		return stream;
 	}
--- a/mt32emu_qt/src/audiodrv/AudioFileWriterDriver.h
+++ b/mt32emu_qt/src/audiodrv/AudioFileWriterDriver.h
@@ -7,7 +7,7 @@
 #include "../AudioFileWriter.h"

 class Master;
-class QSynth;
+class SynthRoute;
 class AudioFileWriterDriver;
 class AudioFileWriterDevice;

@@ -16,7 +16,7 @@ private:
 	AudioFileRenderer writer;

 public:
-	AudioFileWriterStream(const AudioDriverSettings &settings, QSynth &useSynth, const quint32 useSampleRate);
+	AudioFileWriterStream(const AudioDriverSettings &settings, SynthRoute &useSynthRoute, const quint32 useSampleRate);
 	quint64 estimateMIDITimestamp(const MasterClockNanos refNanos = 0);
 	bool start();
 	void close();
@@ -27,7 +27,7 @@ friend class AudioFileWriterDriver;
 private:
 	AudioFileWriterDevice(AudioFileWriterDriver &driver, QString useDeviceName);
 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class AudioFileWriterDriver : public AudioDriver {
--- a/mt32emu_qt/src/audiodrv/CoreAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/CoreAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -23,8 +23,8 @@ static const uint DEFAULT_CHUNK_MS = 20;
 static const uint DEFAULT_AUDIO_LATENCY = 60;
 static const uint DEFAULT_MIDI_LATENCY = 30;

-CoreAudioStream::CoreAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate), audioQueue(NULL)
+CoreAudioStream::CoreAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, quint32 useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate), audioQueue(NULL)
 {
 	const uint bufferSize = (settings.chunkLen * sampleRate) / MasterClock::MILLIS_PER_SECOND;
 	bufferByteSize = bufferSize << 2;
@@ -66,7 +66,7 @@ void CoreAudioStream::renderOutputBuffer(void *userData, AudioQueueRef queue, Au
 	stream->updateTimeInfo(nanosNow, framesInAudioBuffer);

 	uint frameCount = buffer->mAudioDataByteSize >> 2;
-	stream->synth.render((MT32Emu::Bit16s *)buffer->mAudioData, frameCount);
+	stream->synthRoute.render((MT32Emu::Bit16s *)buffer->mAudioData, frameCount);
 	stream->renderedFramesCount += frameCount;

 	OSStatus res = AudioQueueEnqueueBuffer(queue, buffer, 0, NULL);
@@ -123,7 +123,7 @@ void CoreAudioStream::close() {
 CoreAudioDevice::CoreAudioDevice(CoreAudioDriver &driver) :
 	AudioDevice(driver, "Default output device") {}

-AudioStream *CoreAudioDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
+AudioStream *CoreAudioDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
 	CoreAudioStream *stream = new CoreAudioStream(driver.getAudioSettings(), synth, sampleRate);
 	if (stream->start()) {
 		return (AudioStream *)stream;
--- a/mt32emu_qt/src/audiodrv/CoreAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/CoreAudioDriver.h
@@ -5,7 +5,7 @@

 #include "AudioDriver.h"

-class QSynth;
+class SynthRoute;
 class Master;
 class CoreAudioDriver;

@@ -19,7 +19,7 @@ private:
 	static void renderOutputBuffer(void *userData, AudioQueueRef queue, AudioQueueBufferRef buffer);

 public:
-	CoreAudioStream(const AudioDriverSettings &settings, QSynth &synth, const quint32 sampleRate);
+	CoreAudioStream(const AudioDriverSettings &settings, SynthRoute &synthRoute, const quint32 sampleRate);
 	~CoreAudioStream();
 	bool start();
 	void close();
@@ -31,7 +31,7 @@ private:
 	CoreAudioDevice(CoreAudioDriver &driver);

 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class CoreAudioDriver : public AudioDriver {
--- a/mt32emu_qt/src/audiodrv/JACKAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/JACKAudioDriver.cpp
@@ -26,7 +26,7 @@ static const uint MINIMUM_JACK_BUFFER_COUNT = 2;
 static const uint FRAME_BYTE_SIZE = sizeof(float[CHANNEL_COUNT]);

 class JACKAudioProcessor : QThread {
-	QSynth &qsynth;
+	SynthRoute &synthRoute;
 	JACKRingBuffer * const buffer;
 	volatile bool stopProcessing;

@@ -48,15 +48,15 @@ class JACKAudioProcessor : QThread {
 			if (framesToRender == 0) {
 				bufferDataRetrievals.acquire(currentRetrievals + 1);
 			} else {
-				qsynth.render(writePointer, framesToRender);
+				synthRoute.render(writePointer, framesToRender);
 				buffer->advanceWritePointer(framesToRender * FRAME_BYTE_SIZE);
 			}
 		}
 	}

 public:
-	JACKAudioProcessor(QSynth &useQSynth, quint32 bufferSizeFrames) :
-		qsynth(useQSynth),
+	JACKAudioProcessor(SynthRoute &useSynthRoute, quint32 bufferSizeFrames) :
+		synthRoute(useSynthRoute),
 		// JACKRingBuffer needs a bit of spare space to accommodate the entire requested size.
 		// Adding 1 FRAME_BYTE_SIZE does the trick yet ensures proper alignment of pointers.
 		buffer(new JACKRingBuffer((bufferSizeFrames + 1) * FRAME_BYTE_SIZE)),
@@ -91,8 +91,8 @@ public:
 	}
 };

-JACKAudioStream::JACKAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate), jackClient(new JACKClient), buffer(), processor()
+JACKAudioStream::JACKAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate), jackClient(new JACKClient), buffer(), processor()
 {}

 JACKAudioStream::~JACKAudioStream() {
@@ -116,7 +116,7 @@ bool JACKAudioStream::start(MidiSession *midiSession) {
 		// Use prerendering to prevent the realtime thread from locking, yet to retain complete functionality.
 		// Additional latency of at least the JACK buffer length is introduced.
 		if (audioLatencyFrames < jackBufferSize) audioLatencyFrames = jackBufferSize;
-		processor = new JACKAudioProcessor(synth, audioLatencyFrames);
+		processor = new JACKAudioProcessor(synthRoute, audioLatencyFrames);
 		processor->start();
 		qDebug() << "JACKAudioDriver: Configured prerendering audio buffer size (s):" << double(audioLatencyFrames) / sampleRate;
 	} else {
@@ -133,7 +133,7 @@ bool JACKAudioStream::start(MidiSession *midiSession) {
 		// MIDI processing is synchronous, zero latency introduced
 		midiLatencyFrames = 0;
 		qDebug() << "JACKAudioDriver: Configured synchronous MIDI processing";
-		if (jackClient->isRealtimeProcessing()) synth.setRealtime();
+		if (jackClient->isRealtimeProcessing()) synthRoute.enableRealtimeMode();
 	}

 	return true;
@@ -150,7 +150,7 @@ void JACKAudioStream::stop() {

 void JACKAudioStream::onJACKShutdown() {
 	qDebug() << "JACKAudioDriver: JACK server is shutting down, closing synth";
-	synth.close();
+	synthRoute.audioStreamFailed();
 }

 void JACKAudioStream::renderStreams(const quint32 totalFrameCount, JACKAudioSample *leftOutBuffer, JACKAudioSample *rightOutBuffer) {
@@ -180,7 +180,7 @@ void JACKAudioStream::renderStreams(const quint32 totalFrameCount, JACKAudioSamp
 		} else {
 			bufferPtr = buffer;
 			framesToRender = qMin(framesLeft, MT32Emu::MAX_SAMPLES_PER_RUN);
-			synth.render(buffer, framesToRender);
+			synthRoute.render(buffer, framesToRender);
 		}
 		for (JACKAudioSample *leftOutBufferEnd = leftOutBuffer + framesToRender; leftOutBuffer < leftOutBufferEnd;) {
 			*(leftOutBuffer++) = JACKAudioSample(*(bufferPtr++));
@@ -192,20 +192,16 @@ void JACKAudioStream::renderStreams(const quint32 totalFrameCount, JACKAudioSamp
 	renderedFramesCount += totalFrameCount;
 }

-quint64 JACKAudioStream::computeMIDITimestamp(const quint32 jackBufferFrameTime) const {
-	return renderedFramesCount + jackBufferFrameTime;
-}
-
 JACKAudioDefaultDevice::JACKAudioDefaultDevice(JACKAudioDriver &useDriver) :
 	AudioDevice(useDriver, "Default")
 {}

-AudioStream *JACKAudioDefaultDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
-	return startAudioStream(this, synth, sampleRate, NULL);
+AudioStream *JACKAudioDefaultDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
+	return startAudioStream(this, synthRoute, sampleRate, NULL);
 }

-AudioStream *JACKAudioDefaultDevice::startAudioStream(const AudioDevice *audioDevice, QSynth &synth, const uint sampleRate, MidiSession *midiSession) {
-	JACKAudioStream *stream = new JACKAudioStream(audioDevice->driver.getAudioSettings(), synth, sampleRate);
+AudioStream *JACKAudioDefaultDevice::startAudioStream(const AudioDevice *audioDevice, SynthRoute &synthRoute, const uint sampleRate, MidiSession *midiSession) {
+	JACKAudioStream *stream = new JACKAudioStream(audioDevice->driver.getAudioSettings(), synthRoute, sampleRate);
 	if (stream->start(midiSession)) return stream;
 	delete stream;
 	return NULL;
--- a/mt32emu_qt/src/audiodrv/JACKAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/JACKAudioDriver.h
@@ -8,7 +8,7 @@
 typedef float JACKAudioSample;

 class Master;
-class QSynth;
+class SynthRoute;
 class JACKClient;
 class JACKAudioDriver;
 class JACKAudioProcessor;
@@ -16,13 +16,12 @@ class MidiSession;

 class JACKAudioStream : public AudioStream {
 public:
-	JACKAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate);
+	JACKAudioStream(const AudioDriverSettings &useSettings, SynthRoute &synthRoute, const quint32 useSampleRate);
 	~JACKAudioStream();
 	bool start(MidiSession *midiSession);
 	void stop();
 	void onJACKShutdown();
 	void renderStreams(const quint32 frameCount, JACKAudioSample *leftOutBuffer, JACKAudioSample *rightOutBuffer);
-	quint64 computeMIDITimestamp(const quint32 jackBufferFrameTime) const;

 private:
 	JACKClient * const jackClient;
@@ -33,9 +32,9 @@ private:
 class JACKAudioDefaultDevice : public AudioDevice {
 	friend class JACKAudioDriver;
 public:
-	static AudioStream *startAudioStream(const AudioDevice *audioDevice, QSynth &synth, const uint sampleRate, MidiSession *midiSession);
+	static AudioStream *startAudioStream(const AudioDevice *audioDevice, SynthRoute &synthRoute, const uint sampleRate, MidiSession *midiSession);

-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;

 private:
 	JACKAudioDefaultDevice(JACKAudioDriver &driver);
--- a/mt32emu_qt/src/audiodrv/OSSAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/OSSAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -34,8 +34,8 @@ static const unsigned int DEFAULT_AUDIO_LATENCY = 32;
 static const unsigned int DEFAULT_MIDI_LATENCY = 16;
 static const char deviceName[] = "/dev/dsp";

-OSSAudioStream::OSSAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate), buffer(NULL), stream(0), processingThreadID(0), stopProcessing(false)
+OSSAudioStream::OSSAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate), buffer(NULL), stream(0), processingThreadID(0), stopProcessing(false)
 {
 	bufferSize = settings.chunkLen * sampleRate / MasterClock::MILLIS_PER_SECOND;
 }
@@ -81,7 +81,7 @@ void *OSSAudioStream::processingThread(void *userData) {
 	if (isErrorOccured) {
 		close(audioStream.stream);
 		audioStream.stream = 0;
-		audioStream.synth.close();
+		audioStream.synthRoute.audioStreamFailed();
 	} else {
 		audioStream.stopProcessing = false;
 	}
@@ -232,8 +232,8 @@ void OSSAudioStream::stop() {

 OSSAudioDefaultDevice::OSSAudioDefaultDevice(OSSAudioDriver &driver) : AudioDevice(driver, "Default") {}

-AudioStream *OSSAudioDefaultDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
-	OSSAudioStream *stream = new OSSAudioStream(driver.getAudioSettings(), synth, sampleRate);
+AudioStream *OSSAudioDefaultDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
+	OSSAudioStream *stream = new OSSAudioStream(driver.getAudioSettings(), synthRoute, sampleRate);
 	if (stream->start()) return stream;
 	delete stream;
 	return NULL;
--- a/mt32emu_qt/src/audiodrv/OSSAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/OSSAudioDriver.h
@@ -8,7 +8,7 @@
 #include "AudioDriver.h"

 class Master;
-class QSynth;
+class SynthRoute;
 class OSSAudioDriver;

 class OSSAudioStream : public AudioStream {
@@ -22,7 +22,7 @@ private:
 	static void *processingThread(void *);

 public:
-	OSSAudioStream(const AudioDriverSettings &settings, QSynth &synth, const quint32 sampleRate);
+	OSSAudioStream(const AudioDriverSettings &settings, SynthRoute &synthRoute, const quint32 sampleRate);
 	~OSSAudioStream();
 	bool start();
 	void stop();
@@ -32,7 +32,7 @@ class OSSAudioDefaultDevice : public AudioDevice {
 friend class OSSAudioDriver;
 	OSSAudioDefaultDevice(OSSAudioDriver &driver);
 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class OSSAudioDriver : public AudioDriver {
--- a/mt32emu_qt/src/audiodrv/PortAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/PortAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -17,7 +17,6 @@
 #include "PortAudioDriver.h"

 #include "../Master.h"
-#include "../QSynth.h"

 using namespace MT32Emu;

@@ -58,8 +57,8 @@ static void dumpPortAudioDevices() {
 	}
 }

-PortAudioStream::PortAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate), stream(NULL) {}
+PortAudioStream::PortAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, quint32 useSampleRate) :
+  AudioStream(useSettings, useSynthRoute, useSampleRate), stream(NULL) {}

 PortAudioStream::~PortAudioStream() {
 	close();
@@ -137,7 +136,7 @@ int PortAudioStream::paCallback(const void *inputBuffer, void *outputBuffer, uns
 	}
 	stream->updateTimeInfo(nanosNow, framesInAudioBuffer);

-	stream->synth.render((Bit16s *)outputBuffer, frameCount);
+	stream->synthRoute.render((Bit16s *)outputBuffer, frameCount);
 	stream->renderedFramesCount += frameCount;
 	return paContinue;
 }
@@ -152,10 +151,10 @@ void PortAudioStream::close() {
 }

 PortAudioDevice::PortAudioDevice(PortAudioDriver &driver, int useDeviceIndex, QString useDeviceName) :
-	AudioDevice(driver, useDeviceName), deviceIndex(useDeviceIndex) {}
+  AudioDevice(driver, useDeviceName), deviceIndex(useDeviceIndex) {}

-AudioStream *PortAudioDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
-	PortAudioStream *stream = new PortAudioStream(driver.getAudioSettings(), synth, sampleRate);
+AudioStream *PortAudioDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
+	PortAudioStream *stream = new PortAudioStream(driver.getAudioSettings(), synthRoute, sampleRate);
 	if (stream->start(deviceIndex)) {
 		return stream;
 	}
--- a/mt32emu_qt/src/audiodrv/PortAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/PortAudioDriver.h
@@ -9,7 +9,7 @@

 #include "AudioDriver.h"

-class QSynth;
+class SynthRoute;
 class Master;
 class PortAudioDriver;
 class PortAudioDevice;
@@ -21,7 +21,7 @@ private:
 	static int paCallback(const void *inputBuffer, void *outputBuffer, unsigned long frameCount, const PaStreamCallbackTimeInfo *timeInfo, PaStreamCallbackFlags statusFlags, void *userData);

 public:
-	PortAudioStream(const AudioDriverSettings &settings, QSynth &synth, const quint32 sampleRate);
+	PortAudioStream(const AudioDriverSettings &settings, SynthRoute &synthRoute, const quint32 sampleRate);
 	~PortAudioStream();
 	bool start(PaDeviceIndex deviceIndex);
 	void close();
@@ -34,7 +34,7 @@ private:
 	PortAudioDevice(PortAudioDriver &driver, int useDeviceIndex, QString useDeviceName);

 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class PortAudioDriver : public AudioDriver {
--- a/mt32emu_qt/src/audiodrv/PulseAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/PulseAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -127,8 +127,8 @@ static bool loadLibrary(bool loadNeeded) {
 	return true;
 }

-PulseAudioStream::PulseAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate), stream(NULL), processingThreadID(0), stopProcessing(false)
+PulseAudioStream::PulseAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate), stream(NULL), processingThreadID(0), stopProcessing(false)
 {
 	bufferSize = settings.chunkLen * sampleRate / MasterClock::MILLIS_PER_SECOND;
 	buffer = new Bit16s[/* channels */ 2 * bufferSize];
@@ -158,7 +158,7 @@ void *PulseAudioStream::processingThread(void *userData) {
 			_pa_simple_free(audioStream.stream);
 			audioStream.stream = NULL;
 			qDebug() << "PulseAudio: Processing thread stopped";
-			audioStream.synth.close();
+			audioStream.synthRoute.audioStreamFailed();
 			audioStream.processingThreadID = 0;
 			return NULL;
 		}
@@ -248,8 +248,8 @@ void PulseAudioStream::close() {

 PulseAudioDefaultDevice::PulseAudioDefaultDevice(PulseAudioDriver &driver) : AudioDevice(driver, "Default") {}

-AudioStream *PulseAudioDefaultDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
-	PulseAudioStream *stream = new PulseAudioStream(driver.getAudioSettings(), synth, sampleRate);
+AudioStream *PulseAudioDefaultDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
+	PulseAudioStream *stream = new PulseAudioStream(driver.getAudioSettings(), synthRoute, sampleRate);
 	if (stream->start()) return stream;
 	delete stream;
 	return NULL;
--- a/mt32emu_qt/src/audiodrv/PulseAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/PulseAudioDriver.h
@@ -10,7 +10,7 @@
 #include "AudioDriver.h"

 class Master;
-class QSynth;
+class SynthRoute;
 class PulseAudioDriver;

 class PulseAudioStream : public AudioStream {
@@ -24,7 +24,7 @@ private:
 	static void *processingThread(void *);

 public:
-	PulseAudioStream(const AudioDriverSettings &settings, QSynth &synth, const quint32 sampleRate);
+	PulseAudioStream(const AudioDriverSettings &settings, SynthRoute &synthRoute, const quint32 sampleRate);
 	~PulseAudioStream();
 	bool start();
 	void close();
@@ -34,7 +34,7 @@ class PulseAudioDefaultDevice : public AudioDevice {
 friend class PulseAudioDriver;
 	PulseAudioDefaultDevice(PulseAudioDriver &driver);
 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class PulseAudioDriver : public AudioDriver {
--- a/mt32emu_qt/src/audiodrv/QtAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/QtAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -53,7 +53,7 @@ public:
 		}
 		stream.updateTimeInfo(nanosNow, framesInAudioBuffer);
 		uint framesToRender = uint(len >> 2);
-		stream.synth.render((Bit16s *)data, framesToRender);
+		stream.synthRoute.render((Bit16s *)data, framesToRender);
 		stream.renderedFramesCount += framesToRender;
 		return len;
 	}
@@ -79,8 +79,8 @@ public:
 	}
 };

-QtAudioStream::QtAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate)
+QtAudioStream::QtAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate)
 {
 	// Creating QAudioOutput in a thread leads to smooth rendering
 	// Rendering will be performed in the main thread otherwise
@@ -128,8 +128,8 @@ void QtAudioStream::close() {

 QtAudioDefaultDevice::QtAudioDefaultDevice(QtAudioDriver &driver) : AudioDevice(driver, "Default") {}

-AudioStream *QtAudioDefaultDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
-	return new QtAudioStream(driver.getAudioSettings(), synth, sampleRate);
+AudioStream *QtAudioDefaultDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
+	return new QtAudioStream(driver.getAudioSettings(), synthRoute, sampleRate);
 }

 QtAudioDriver::QtAudioDriver(Master *useMaster) : AudioDriver("qtaudio", "QtAudio") {
--- a/mt32emu_qt/src/audiodrv/QtAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/QtAudioDriver.h
@@ -9,7 +9,7 @@

 class Master;
 class WaveGenerator;
-class QSynth;
+class SynthRoute;
 class QAudioOutput;
 class QtAudioDriver;

@@ -21,7 +21,7 @@ private:
 	WaveGenerator *waveGenerator;

 public:
-	QtAudioStream(const AudioDriverSettings &useSettings, QSynth &useSynth, const quint32 useSampleRate);
+	QtAudioStream(const AudioDriverSettings &useSettings, SynthRoute &useSynthRoute, const quint32 useSampleRate);
 	~QtAudioStream();
 	void start();
 	void close();
@@ -32,7 +32,7 @@ class QtAudioDefaultDevice : public AudioDevice {
 private:
 	QtAudioDefaultDevice(QtAudioDriver &driver);
 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class QtAudioDriver : public AudioDriver {
--- a/mt32emu_qt/src/audiodrv/WinMMAudioDriver.cpp
+++ b/mt32emu_qt/src/audiodrv/WinMMAudioDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -29,8 +29,8 @@ static const DWORD FRAME_SIZE = 4;
 // Latency for MIDI processing. 15 ms is the offset of interprocess timeGetTime() difference.
 static const DWORD DEFAULT_MIDI_LATENCY = 15;

-WinMMAudioStream::WinMMAudioStream(const AudioDriverSettings &useSettings, bool useRingBufferMode, QSynth &useSynth, const uint useSampleRate) :
-	AudioStream(useSettings, useSynth, useSampleRate),
+WinMMAudioStream::WinMMAudioStream(const AudioDriverSettings &useSettings, bool useRingBufferMode, SynthRoute &useSynthRoute, const uint useSampleRate) :
+	AudioStream(useSettings, useSynthRoute, useSampleRate),
 	hWaveOut(NULL), waveHdr(NULL), hEvent(NULL), hWaitableTimer(NULL), stopProcessing(false),
 	processor(*this), ringBufferMode(useRingBufferMode), prevPlayPosition(0L)
 {
@@ -102,7 +102,7 @@ void WinMMAudioProcessor::run() {
 		const DWORD playCursor = stream.getCurrentPlayPosition();
 		if (playCursor == (DWORD)-1) {
 			stream.stopProcessing = true;
-			stream.synth.close();
+			stream.synthRoute.audioStreamFailed();
 			return;
 		}

@@ -151,12 +151,12 @@ void WinMMAudioProcessor::run() {
 		}
 		DWORD framesInAudioBuffer = playCursor < renderPos ? renderPos - playCursor : (renderPos + stream.audioLatencyFrames) - playCursor;
 		stream.updateTimeInfo(nanosNow, framesInAudioBuffer);
-		stream.synth.render(buf, frameCount);
+		stream.synthRoute.render(buf, frameCount);
 		stream.renderedFramesCount += frameCount;
 		if (!stream.ringBufferMode && waveOutWrite(stream.hWaveOut, waveHdr, sizeof(WAVEHDR)) != MMSYSERR_NOERROR) {
 			qDebug() << "WinMMAudioDriver: waveOutWrite failed, thread stopped";
 			stream.stopProcessing = true;
-			stream.synth.close();
+			stream.synthRoute.audioStreamFailed();
 			return;
 		}
 	}
@@ -264,9 +264,9 @@ WinMMAudioDevice::WinMMAudioDevice(WinMMAudioDriver &driver, int useDeviceIndex,
 	AudioDevice(driver, useDeviceName), deviceIndex(useDeviceIndex) {
 }

-AudioStream *WinMMAudioDevice::startAudioStream(QSynth &synth, const uint sampleRate) const {
+AudioStream *WinMMAudioDevice::startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const {
 	WinMMAudioDriver &winDriver = (WinMMAudioDriver &)driver;
-	WinMMAudioStream *stream = new WinMMAudioStream(winDriver.getAudioStreamSettings(), winDriver.isRingBufferMode(), synth, sampleRate);
+	WinMMAudioStream *stream = new WinMMAudioStream(winDriver.getAudioStreamSettings(), winDriver.isRingBufferMode(), synthRoute, sampleRate);
 	if (stream->start(deviceIndex)) {
 		return stream;
 	}
--- a/mt32emu_qt/src/audiodrv/WinMMAudioDriver.h
+++ b/mt32emu_qt/src/audiodrv/WinMMAudioDriver.h
@@ -13,6 +13,7 @@
 #endif

 class Master;
+class SynthRoute;
 class WinMMAudioDriver;
 class WinMMAudioDevice;
 class WinMMAudioStream;
@@ -32,7 +33,7 @@ class WinMMAudioStream : public AudioStream {
 	friend class WinMMAudioProcessor;
 private:
 	HWAVEOUT hWaveOut;
-	WAVEHDR	 *waveHdr;
+	WAVEHDR *waveHdr;
 	HANDLE hEvent;
 	HANDLE hWaitableTimer;

@@ -47,7 +48,7 @@ private:
 	DWORD getCurrentPlayPosition();

 public:
-	WinMMAudioStream(const AudioDriverSettings &useSettings, bool ringBufferMode, QSynth &useSynth, uint useSampleRate);
+	WinMMAudioStream(const AudioDriverSettings &useSettings, bool ringBufferMode, SynthRoute &synthRoute, uint useSampleRate);
 	~WinMMAudioStream();
 	bool start(int deviceIndex);
 	void close();
@@ -59,7 +60,7 @@ private:
 	UINT deviceIndex;
 	WinMMAudioDevice(WinMMAudioDriver &driver, int useDeviceIndex, QString useDeviceName);
 public:
-	AudioStream *startAudioStream(QSynth &synth, const uint sampleRate) const;
+	AudioStream *startAudioStream(SynthRoute &synthRoute, const uint sampleRate) const;
 };

 class WinMMAudioDriver : public AudioDriver {
--- a/mt32emu_qt/src/mididrv/ALSADriver.cpp
+++ b/mt32emu_qt/src/mididrv/ALSADriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -92,7 +92,7 @@ void ALSAMidiDriver::processSeqEvents() {
 				showBalloon("Connected application:", appName);
 				qDebug() << "ALSAMidiDriver: Connected application" << appName;
 			}
-			if (processSeqEvent(seq_event, midiSession->getSynthRoute())) {
+			if (processSeqEvent(seq_event, midiSession)) {
 				break;
 			}
 		} while (!stopProcessing && snd_seq_event_input_pending(snd_seq, 1));
@@ -134,7 +134,8 @@ MidiSession *ALSAMidiDriver::findMidiSessionForClient(unsigned int clientAddr) {
 	return midiSessions.at(i);
 }

-bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *synthRoute) {
+bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, MidiSession *midiSession) {
+	SynthRoute *synthRoute = midiSession->getSynthRoute();
 	MT32Emu::Bit32u msg = 0;
 	switch(seq_event->type) {
 	case SND_SEQ_EVENT_NOTEON:
@@ -142,7 +143,7 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		msg |= seq_event->data.note.channel;
 		msg |= seq_event->data.note.note << 8;
 		msg |= seq_event->data.note.velocity << 16;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

 	case SND_SEQ_EVENT_NOTEOFF:
@@ -150,7 +151,7 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		msg |= seq_event->data.note.channel;
 		msg |= seq_event->data.note.note << 8;
 		msg |= seq_event->data.note.velocity << 16;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

 	case SND_SEQ_EVENT_CONTROLLER:
@@ -158,7 +159,7 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		msg |= seq_event->data.control.channel;
 		msg |= seq_event->data.control.param << 8;
 		msg |= seq_event->data.control.value << 16;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

 	case SND_SEQ_EVENT_CONTROL14:
@@ -169,7 +170,7 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		msg |= seq_event->data.control.channel;
 		msg |= seq_event->data.control.param << 8;
 		msg |= (seq_event->data.control.value >> 7) << 16;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

 	case SND_SEQ_EVENT_NONREGPARAM:
@@ -181,23 +182,23 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		if (seq_event->data.control.param != 0) break;
 		msg = 0x64B0;
 		msg |= seq_event->data.control.channel;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());

 		msg &= 0xFF;
 		msg |= 0x6500;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());

 		msg &= 0xFF;
 		msg |= 0x0600;
 		msg |= ((seq_event->data.control.value >> 7) & 0x7F) << 16;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

 	case SND_SEQ_EVENT_PGMCHANGE:
 		msg = 0xC0;
 		msg |= seq_event->data.control.channel;
 		msg |= seq_event->data.control.value << 8;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

 	case SND_SEQ_EVENT_PITCHBEND:
@@ -207,11 +208,10 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		bend = seq_event->data.control.value + 8192;
 		msg |= (bend & 0x7F) << 8;
 		msg |= ((bend >> 7) & 0x7F) << 16;
-		synthRoute->pushMIDIShortMessage(msg, MasterClock::getClockNanos());
+		synthRoute->pushMIDIShortMessage(*midiSession, msg, MasterClock::getClockNanos());
 		break;

-	case SND_SEQ_EVENT_SYSEX:
-	{
+	case SND_SEQ_EVENT_SYSEX: {
 		MT32Emu::Bit8u *sysexData = (MT32Emu::Bit8u *)seq_event->data.ext.ptr;
 		uint sysexLength = seq_event->data.ext.len;

@@ -222,13 +222,13 @@ bool ALSAMidiDriver::processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *syn
 		bool hasSysexStart = sysexData[0] == MIDI_CMD_COMMON_SYSEX;
 		bool hasSysexEnd = sysexData[sysexLength - 1] == MIDI_CMD_COMMON_SYSEX_END;
 		if (hasSysexStart && hasSysexEnd) {
-			synthRoute->pushMIDISysex(sysexData, sysexLength, MasterClock::getClockNanos());
+			synthRoute->pushMIDISysex(*midiSession, sysexData, sysexLength, MasterClock::getClockNanos());
 			break;
 		}
 		// OK, accumulate SysEx data received so far and commit when ready.
 		sysexBuffer.append(sysexData, sysexLength);
 		if (hasSysexEnd) {
-			synthRoute->pushMIDISysex(sysexBuffer.constData(), sysexBuffer.size(), MasterClock::getClockNanos());
+			synthRoute->pushMIDISysex(*midiSession, sysexBuffer.constData(), sysexBuffer.size(), MasterClock::getClockNanos());
 			sysexBuffer.clear();
 		}
 		break;
@@ -276,12 +276,15 @@ int ALSAMidiDriver::alsa_setup_midi() {
 	}

 	snd_seq_set_client_name(snd_seq, "Munt MT-32");
-	seqPort = snd_seq_create_simple_port(snd_seq, "Standard",
-						SND_SEQ_PORT_CAP_SUBS_WRITE |
-						SND_SEQ_PORT_CAP_WRITE,
-						SND_SEQ_PORT_TYPE_MIDI_GENERIC |
-						SND_SEQ_PORT_TYPE_MIDI_MT32 |
-						SND_SEQ_PORT_TYPE_SYNTHESIZER);
+	seqPort = snd_seq_create_simple_port(
+		snd_seq,
+		"Standard",
+		SND_SEQ_PORT_CAP_SUBS_WRITE |
+		SND_SEQ_PORT_CAP_WRITE,
+		SND_SEQ_PORT_TYPE_MIDI_GENERIC |
+		SND_SEQ_PORT_TYPE_MIDI_MT32 |
+		SND_SEQ_PORT_TYPE_SYNTHESIZER
+	);
 	if (seqPort < 0) {
 		qDebug() << "ALSAMidiDriver: Error creating sequencer port";
 		return -1;
--- a/mt32emu_qt/src/mididrv/ALSADriver.h
+++ b/mt32emu_qt/src/mididrv/ALSADriver.h
@@ -31,7 +31,7 @@ private:
 	static void *processingThread(void *userData);
 	int alsa_setup_midi();
 	void processSeqEvents();
-	bool processSeqEvent(snd_seq_event_t *seq_event, SynthRoute *synthRoute);
+	bool processSeqEvent(snd_seq_event_t *seq_event, MidiSession *midiSession);
 	unsigned int getSourceAddr(snd_seq_event_t *seq_event);
 	QString getClientName(unsigned int clientAddr);
 	MidiSession *findMidiSessionForClient(unsigned int clientAddr);
--- a/mt32emu_qt/src/mididrv/JACKMidiDriver.cpp
+++ b/mt32emu_qt/src/mididrv/JACKMidiDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -40,19 +40,19 @@ MasterClockNanos JACKMidiDriver::jackFrameTimeToMasterClockNanos(MasterClockNano
 bool JACKMidiDriver::pushMIDIMessage(MidiSession *midiSession, MasterClockNanos eventTimestamp, size_t midiBufferSize, uchar *midiBuffer) {
 	SynthRoute *synthRoute = midiSession->getSynthRoute();
 	if (*midiBuffer == 0xF0) {
-		return synthRoute->pushMIDISysex(midiBuffer, uint(midiBufferSize), eventTimestamp);
+		return synthRoute->pushMIDISysex(*midiSession, midiBuffer, uint(midiBufferSize), eventTimestamp);
 	}
 	quint32 message = midiBufferToShortMessage(midiBufferSize, midiBuffer);
-	return synthRoute->pushMIDIShortMessage(message, eventTimestamp);
+	return synthRoute->pushMIDIShortMessage(*midiSession, message, eventTimestamp);
 }

 bool JACKMidiDriver::playMIDIMessage(MidiSession *midiSession, quint64 eventTimestamp, size_t midiBufferSize, uchar *midiBuffer) {
 	SynthRoute *synthRoute = midiSession->getSynthRoute();
 	if (*midiBuffer == 0xF0) {
-		return synthRoute->playMIDISysex(midiBuffer, quint32(midiBufferSize), eventTimestamp);
+		return synthRoute->playMIDISysex(*midiSession, midiBuffer, quint32(midiBufferSize), eventTimestamp);
 	}
 	quint32 message = midiBufferToShortMessage(midiBufferSize, midiBuffer);
-	return synthRoute->playMIDIShortMessage(message, eventTimestamp);
+	return synthRoute->playMIDIShortMessage(*midiSession, message, eventTimestamp);
 }

 JACKMidiDriver::JACKMidiDriver(Master *master) : MidiDriver(master) {
--- a/mt32emu_qt/src/mididrv/MidiDriver.cpp
+++ b/mt32emu_qt/src/mididrv/MidiDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
--- a/mt32emu_qt/src/mididrv/SMFDriver.cpp
+++ b/mt32emu_qt/src/mididrv/SMFDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -132,10 +132,10 @@ void SMFProcessor::run() {
 		if (stopProcessing || synthRoute->getState() != SynthRouteState_OPEN) break;
 		switch (e.getType()) {
 			case SHORT_MESSAGE:
-				synthRoute->pushMIDIShortMessage(e.getShortMessage(), currentNanos);
+				synthRoute->pushMIDIShortMessage(*session, e.getShortMessage(), currentNanos);
 				break;
 			case SYSEX:
-				synthRoute->pushMIDISysex(e.getSysexData(), e.getSysexLen(), currentNanos);
+				synthRoute->pushMIDISysex(*session, e.getSysexData(), e.getSysexLen(), currentNanos);
 				break;
 			case SET_TEMPO: {
 				uint tempo = e.getShortMessage();
--- a/mt32emu_qt/src/mididrv/TestDriver.cpp
+++ b/mt32emu_qt/src/mididrv/TestDriver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -42,10 +42,10 @@ void TestProcessor::run() {
 	qDebug() << currentNanos;
 	bool alt = false;
 	while (!stopProcessing) {
-		session1->getSynthRoute()->pushMIDIShortMessage(0, currentNanos);
+		session1->getSynthRoute()->pushMIDIShortMessage(*session1, 0, currentNanos);
 		// Test 2 sends an event at the same time as every second Test 1 event
 		if(alt && session2 != NULL)
-			session2->getSynthRoute()->pushMIDIShortMessage(0, currentNanos);
+			session2->getSynthRoute()->pushMIDIShortMessage(*session2, 0, currentNanos);
 		alt = !alt;
 		currentNanos += TEST1_EVENT_INTERVAL_NANOS;
 		MasterClock::sleepUntilClockNanos(currentNanos);
--- a/mt32emu_qt/src/mididrv/Win32Driver.cpp
+++ b/mt32emu_qt/src/mididrv/Win32Driver.cpp
@@ -1,4 +1,4 @@
-/* Copyright (C) 2011-2019 Jerome Fisher, Sergey V. Mikayev
+/* Copyright (C) 2011-2020 Jerome Fisher, Sergey V. Mikayev
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
@@ -176,7 +176,7 @@ LRESULT CALLBACK Win32MidiDriver::midiInProc(HWND hwnd, UINT uMsg, WPARAM wParam
 				}
 				LARGE_INTEGER t = { { data[2], (LONG)data[3] } };
 //				qDebug() << "D" << 1e-6 * ((t.QuadPart - startMasterClock) - MasterClock::getClockNanos());
-				midiSession->getSynthRoute()->pushMIDIShortMessage(data[4], t.QuadPart - startMasterClock);
+				midiSession->getSynthRoute()->pushMIDIShortMessage(*midiSession, data[4], t.QuadPart - startMasterClock);
 				return 1;
 			}
 		} else {
@@ -186,7 +186,7 @@ LRESULT CALLBACK Win32MidiDriver::midiInProc(HWND hwnd, UINT uMsg, WPARAM wParam
 				qDebug() << "Win32MidiDriver: Invalid midiSession ID supplied:" << "0x" + QString::number(midiSessionID, 16);
 				return 0;
 			}
-			midiSession->getSynthRoute()->pushMIDISysex((MT32Emu::Bit8u *)cds->lpData, cds->cbData, MasterClock::getClockNanos());
+			midiSession->getSynthRoute()->pushMIDISysex(*midiSession, (MT32Emu::Bit8u *)cds->lpData, cds->cbData, MasterClock::getClockNanos());
 			return 1;
 		}
 	}
@@ -392,7 +392,7 @@ void CALLBACK Win32MidiIn::midiInProc(HMIDIIN hMidiIn, UINT wMsg, DWORD_PTR dwIn
 	if (wMsg == MIM_DATA) {
 		// No need to use QMidiStreamParser for short messages: they are guaranteed to have explicit status byte
 		// if ((dwParam1 & 0xF8) == 0xF8) // No support for System Realtime yet
-		midiSession->getSynthRoute()->pushMIDIShortMessage(dwParam1, MasterClock::getClockNanos());
+		midiSession->getSynthRoute()->pushMIDIShortMessage(*midiSession, dwParam1, MasterClock::getClockNanos());
 	}
 }