major rewrite

22 files changed, 334 insertions, 421 deletions

diff --git a/sdrbase/audio/audiodeviceinfo.cpp b/sdrbase/audio/audiodeviceinfo.cpp
deleted file mode 100644
index e422878..0000000
--- a/sdrbase/audio/audiodeviceinfo.cpp
+++ /dev/null
@@ -1,28 +0,0 @@
-///////////////////////////////////////////////////////////////////////////////////
-// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
-// written by Christian Daniel                                                   //
-//                                                                               //
-// 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          //
-// the Free Software Foundation as version 3 of the License, or                  //
-//                                                                               //
-// This program is distributed in the hope that it will be useful,               //
-// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
-// GNU General Public License V3 for more details.                               //
-//                                                                               //
-// You should have received a copy of the GNU General Public License             //
-// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
-///////////////////////////////////////////////////////////////////////////////////
-
-#include "audio/audiodeviceinfo.h"
-
-AudioDeviceInfo::AudioDeviceInfo()
-{
-}
-
-int AudioDeviceInfo::match(const QString& api, const QString device) const
-{
-	// nothing found - fall back to default
-	return 0;
-}
diff --git a/sdrbase/audio/audiofifo.cpp b/sdrbase/audio/audiofifo.cpp
index dd475ca..41d19df 100644
--- a/sdrbase/audio/audiofifo.cpp
+++ b/sdrbase/audio/audiofifo.cpp
@@ -22,7 +22,9 @@
 #define MIN(x, y) ((x) < (y) ? (x) : (y))
 
 AudioFifo::AudioFifo() :
-	m_fifo(NULL)
+	m_fifo(NULL),
+	m_sampleRate(0),
+	m_stopped(true)
 {
 	m_size = 0;
 	m_fill = 0;
diff --git a/sdrbase/audio/audiooutput.cpp b/sdrbase/audio/audiooutput.cpp
index 455241a..b5e1792 100644
--- a/sdrbase/audio/audiooutput.cpp
+++ b/sdrbase/audio/audiooutput.cpp
@@ -24,6 +24,9 @@
 
 AudioOutput::AudioOutput() :
 	m_mutex(),
+	m_error(),
+	m_deviceName(),
+	m_rate(0),
 	m_audioOutput(NULL),
 	m_audioFifos()
 {
@@ -39,17 +42,38 @@ AudioOutput::~AudioOutput()
 	m_audioFifos.clear();
 }
 
-bool AudioOutput::start(int device, int rate)
+void AudioOutput::configure(const QString& deviceName, uint rate)
 {
 	QMutexLocker mutexLocker(&m_mutex);
 
-	Q_UNUSED(device);
-	Q_UNUSED(rate);
+	m_deviceName = deviceName;
+	m_rate = rate;
+}
+
+bool AudioOutput::start()
+{
+	QMutexLocker mutexLocker(&m_mutex);
 
 	QAudioFormat format;
 	QAudioDeviceInfo devInfo(QAudioDeviceInfo::defaultOutputDevice());
 
-	format.setSampleRate(41000);
+	if(!m_deviceName.isEmpty()) {
+		QList<QAudioDeviceInfo> devices = QAudioDeviceInfo::availableDevices(QAudio::AudioOutput);
+		bool found = false;
+		for(int i = 0; i < devices.count(); ++i) {
+			if(devices[i].deviceName() == m_deviceName) {
+				devInfo = devices[i];
+				found = true;
+				break;
+			}
+		}
+		if(!found) {
+			m_error = tr("Audio output device %1 not available").arg(m_deviceName);
+			return false;
+		}
+	}
+
+	format.setSampleRate(m_rate);
 	format.setChannelCount(2);
 	format.setSampleSize(16);
 	format.setCodec("audio/pcm");
@@ -60,26 +84,33 @@ bool AudioOutput::start(int device, int rate)
 		qDebug("default format not supported - try to use nearest");
 		format = devInfo.nearestFormat(format);
 	}
+	qDebug("Audio output %s using samplerate %d", qPrintable(devInfo.deviceName()), format.sampleRate());
 
 	if(format.sampleSize() != 16) {
-		qDebug("audio device doesn't support 16 bit samples (%s)", qPrintable(devInfo.defaultOutputDevice().deviceName()));
+		m_error = tr("Audio output %1 doesn't support 16 bit samples").arg(devInfo.deviceName());
 		return false;
 	}
 
-	m_audioOutput = new QAudioOutput(format);
+	m_audioOutput = new QAudioOutput(devInfo, format);
 
 	QIODevice::open(QIODevice::ReadOnly);
 
+	//m_audioOutput->setBufferSize(3 * 4096);
 	m_audioOutput->start(this);
 
-	return true;
+	for(AudioFifos::iterator it = m_audioFifos.begin(); it != m_audioFifos.end(); ++it)
+		(*it)->setSampleRate(m_audioOutput->format().sampleRate());
 
+	return true;
 }
 
 void AudioOutput::stop()
 {
 	QMutexLocker mutexLocker(&m_mutex);
 
+	for(AudioFifos::iterator it = m_audioFifos.begin(); it != m_audioFifos.end(); ++it)
+		(*it)->setSampleRate(0);
+
 	if(m_audioOutput != NULL) {
 		m_audioOutput->stop();
 		delete m_audioOutput;
@@ -92,6 +123,10 @@ void AudioOutput::addFifo(AudioFifo* audioFifo)
 {
 	QMutexLocker mutexLocker(&m_mutex);
 
+	if(m_audioOutput == NULL)
+		audioFifo->setSampleRate(0);
+	else audioFifo->setSampleRate(m_audioOutput->format().sampleRate());
+
 	m_audioFifos.push_back(audioFifo);
 }
 
@@ -99,9 +134,19 @@ void AudioOutput::removeFifo(AudioFifo* audioFifo)
 {
 	QMutexLocker mutexLocker(&m_mutex);
 
+	audioFifo->setSampleRate(0);
 	m_audioFifos.remove(audioFifo);
 }
 
+quint32 AudioOutput::getCurrentRate()
+{
+	QMutexLocker mutexLocker(&m_mutex);
+
+	if(m_audioOutput == NULL)
+		return 0;
+	else return m_audioOutput->format().sampleRate();
+}
+
 bool AudioOutput::open(OpenMode mode)
 {
 	Q_UNUSED(mode);
@@ -110,9 +155,6 @@ bool AudioOutput::open(OpenMode mode)
 
 qint64 AudioOutput::readData(char* data, qint64 maxLen)
 {
-	if(maxLen == 0)
-		return 0;
-
 	QMutexLocker mutexLocker(&m_mutex);
 
 	maxLen -= maxLen % 4;
@@ -120,13 +162,18 @@ qint64 AudioOutput::readData(char* data, qint64 maxLen)
 
 	if((int)m_mixBuffer.size() < framesPerBuffer * 2) {
 		m_mixBuffer.resize(framesPerBuffer * 2); // allocate 2 qint32 per frame (stereo)
-		if(m_mixBuffer.size() != framesPerBuffer * 2)
+		if(m_mixBuffer.size() != framesPerBuffer * 2) {
+			qDebug("KAPUTT");
 			return 0;
+		}
 	}
 	memset(&m_mixBuffer[0], 0x00, 2 * framesPerBuffer * sizeof(m_mixBuffer[0])); // start with silence
 
 	// sum up a block from all fifos
 	for(AudioFifos::iterator it = m_audioFifos.begin(); it != m_audioFifos.end(); ++it) {
+		if((*it)->isStopped())
+			continue;
+
 		// use outputBuffer as temp - yes, one memcpy could be saved
 		uint samples = (*it)->read((quint8*)data, framesPerBuffer, 1);
 		const qint16* src = (const qint16*)data;
@@ -141,7 +188,7 @@ qint64 AudioOutput::readData(char* data, qint64 maxLen)
 		}
 	}
 
-	// convert to int16
+	// convert to int16 and do saturation
 	std::vector<qint32>::const_iterator src = m_mixBuffer.begin();
 	qint16* dst = (qint16*)data;
 	for(int i = 0; i < framesPerBuffer; ++i) {
diff --git a/sdrbase/dsp/channelizer.cpp b/sdrbase/dsp/channelizer.cpp
index 2028a0f..41300e1 100644
--- a/sdrbase/dsp/channelizer.cpp
+++ b/sdrbase/dsp/channelizer.cpp
@@ -27,13 +27,15 @@ void Channelizer::feed(SampleVector::const_iterator begin, SampleVector::const_i
 {
 	for(SampleVector::const_iterator sample = begin; sample != end; ++sample) {
 		Sample s(*sample);
+		bool haveSample = true;
 		FilterStages::iterator stage = m_filterStages.begin();
 		while(stage != m_filterStages.end()) {
-			if(!(*stage)->work(&s))
+			haveSample = (*stage)->work(&s);
+			if(!haveSample)
 				break;
 			++stage;
 		}
-		if(stage == m_filterStages.end())
+		if((stage == m_filterStages.end()) && haveSample)
 			m_sampleBuffer.push_back(s);
 	}
 
@@ -58,7 +60,7 @@ void Channelizer::stop()
 bool Channelizer::handleMessage(Message* cmd)
 {
 	if(DSPSignalNotification::match(cmd)) {
-		DSPSignalNotification* signal = (DSPSignalNotification*)cmd;
+		DSPSignalNotification* signal = DSPSignalNotification::cast(cmd);
 		m_inputSampleRate = signal->getSampleRate();
 		applyConfiguration();
 		cmd->completed();
@@ -69,7 +71,7 @@ bool Channelizer::handleMessage(Message* cmd)
 		}
 		return true;
 	} else if(DSPConfigureChannelizer::match(cmd)) {
-		DSPConfigureChannelizer* chan = (DSPConfigureChannelizer*)cmd;
+		DSPConfigureChannelizer* chan = DSPConfigureChannelizer::cast(cmd);
 		m_requestedOutputSampleRate = chan->getSampleRate();
 		m_requestedCenterFrequency = chan->getCenterFrequency();
 		applyConfiguration();
@@ -172,157 +174,3 @@ void Channelizer::freeFilterChain()
 		delete *it;
 	m_filterStages.clear();
 }
-
-#if 0
-
-///////////////////////////////////////////////////////////////////////////////////
-// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
-// written by Christian Daniel                                                   //
-//                                                                               //
-// 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          //
-// the Free Software Foundation as version 3 of the License, or                  //
-//                                                                               //
-// This program is distributed in the hope that it will be useful,               //
-// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
-// GNU General Public License V3 for more details.                               //
-//                                                                               //
-// You should have received a copy of the GNU General Public License             //
-// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
-///////////////////////////////////////////////////////////////////////////////////
-
-#include <QTime>
-#include <stdio.h>
-#include "channelizer.h"
-#include "hardware/audiooutput.h"
-
-Channelizer::Channelizer()
-{
-#if 0
-	m_spectrum.configure(128 , 25, FFTWindow::Bartlett);
-	m_buffer.resize(2048);
-	m_bufferFill = 0;
-	m_nco.setFreq(-100000, 500000);
-	m_interpolator.create(51, 32, 32 * 500000, 150000 / 2);
-	m_distance = 500000.0 / 176400.0;
-
-	m_interpolator2.create(19, 8, 8 * 176400, 15000 / 2);
-	m_distance2 = 4;
-
-	m_audioFifo.setSize(4, 44100 / 2 * 4);
-	m_audioOutput = new AudioOutput;
-	m_audioOutput->start(0, 44100, &m_audioFifo);
-	m_resampler = 1.0;
-
-	m_resamplerCtrl.setup(0.00001, 0, -0.00001);
-#endif
-}
-
-Channelizer::~Channelizer()
-{
-#if 0
-	m_audioOutput->stop();
-	delete m_audioOutput;
-#endif
-}
-
-#if 0
-void Channelizer::setGLSpectrum(GLSpectrum* glSpectrum)
-{
-	m_spectrum.setGLSpectrum(glSpectrum);
-}
-#endif
-
-size_t Channelizer::workUnitSize()
-{
-#if 0
-	return m_buffer.size();
-#endif
-	return 0;
-}
-
-size_t Channelizer::work(SampleVector::const_iterator begin, SampleVector::const_iterator end)
-{
-#if 0
-	int buffered = m_audioOutput->bufferedSamples();
-
-	if(m_audioFifo.fill() < (m_audioFifo.size() / 6)) {
-		while(m_audioFifo.fill() < (m_audioFifo.size() / 2)) {
-			quint32 d = 0;
-			m_audioFifo.write((quint8*)&d, 4);
-		}
-		qDebug("underflow - fill %d (vs %d)", m_audioFifo.fill(), m_audioFifo.size() / 4 / 2);
-	}
-
-	buffered = m_audioOutput->bufferedSamples();
-	int fill = m_audioFifo.fill() / 4 + buffered;
-	float err = (float)fill / ((m_audioFifo.size() / 4) / 2);
-
-	float ctrl = m_resamplerCtrl.feed(err);
-	//float resamplerRate = (ctrl / 1.0);
-	float resamplerRate = err;
-
-	if(resamplerRate < 0.9999)
-		resamplerRate = 0.9999;
-	else if(resamplerRate > 1.0001)
-		resamplerRate = 1.0001;
-	m_resampler = m_resampler * 0.99 + resamplerRate * 0.01;
-	//m_resampler = resamplerRate;
-
-	if(m_resampler < 0.995)
-		m_resampler = 0.995;
-	else if(m_resampler > 1.005)
-		m_resampler = 1.005;
-
-	//qDebug("%lld %5d %f %f %f", QDateTime::currentMSecsSinceEpoch(), fill, ctrl, m_resampler, err);
-
-	struct AudioSample {
-		qint16 l;
-		qint16 r;
-	};
-
-	size_t count = end - begin;
-	Complex ci;
-	bool consumed;
-	bool consumed2;
-
-	for(SampleVector::const_iterator it = begin; it < end; it++) {
-		Complex c(it->real() / 32768.0, it->imag() / 32768.0);
-		c *= m_nco.nextIQ();
-
-		consumed = false;
-		if(m_interpolator.interpolate(&m_distance, c, &consumed, &ci)) {
-
-			Complex d = ci * conj(m_lastSample);
-			m_lastSample = ci;
-			//Complex demod(atan2(d.imag(), d.real()) * 0.5, 0);
-			Real demod = atan2(d.imag(), d.real()) / M_PI;
-
-			consumed2 = false;
-			c = Complex(demod, 0);
-			while(!consumed2) {
-				if(m_interpolator2.interpolate(&m_distance2, c, &consumed2, &ci)) {
-					m_buffer[m_bufferFill++] = Sample(ci.real() * 32767.0, 0.0);
-
-					AudioSample s;
-					s.l = ci.real() * 32767.0;
-					s.r = s.l;
-					m_audioFifo.write((quint8*)&s, 4, 1);
-
-					if(m_bufferFill >= m_buffer.size()) {
-						m_spectrum.feed(m_buffer.begin(), m_buffer.end());
-						m_bufferFill = 0;
-					}
-					m_distance2 += 4.0 * m_resampler;
-				}
-			}
-			m_distance += 500000 / 176400.0;
-		}
-	}
-
-	return count;
-#endif
-}
-
-#endif
diff --git a/sdrbase/dsp/dspcommands.cpp b/sdrbase/dsp/dspcommands.cpp
index 21bdddc..9e19da2 100644
--- a/sdrbase/dsp/dspcommands.cpp
+++ b/sdrbase/dsp/dspcommands.cpp
@@ -13,6 +13,7 @@ MESSAGE_CLASS_DEFINITION(DSPAddAudioSource, Message)
 MESSAGE_CLASS_DEFINITION(DSPRemoveAudioSource, Message)
 MESSAGE_CLASS_DEFINITION(DSPConfigureSpectrumVis, Message)
 MESSAGE_CLASS_DEFINITION(DSPConfigureCorrection, Message)
+MESSAGE_CLASS_DEFINITION(DSPConfigureAudioOutput, Message)
 MESSAGE_CLASS_DEFINITION(DSPEngineReport, Message)
 MESSAGE_CLASS_DEFINITION(DSPConfigureScopeVis, Message)
 MESSAGE_CLASS_DEFINITION(DSPSignalNotification, Message)
diff --git a/sdrbase/dsp/dspengine.cpp b/sdrbase/dsp/dspengine.cpp
index 369403f..63b3f58 100644
--- a/sdrbase/dsp/dspengine.cpp
+++ b/sdrbase/dsp/dspengine.cpp
@@ -109,6 +109,12 @@ void DSPEngine::configureCorrections(bool dcOffsetCorrection, bool iqImbalanceCo
 	cmd->submit(&m_messageQueue);
 }
 
+void DSPEngine::configureAudioOutput(const QString& audioOutput, quint32 audioOutputRate)
+{
+	Message* cmd = DSPConfigureAudioOutput::create(audioOutput, audioOutputRate);
+	cmd->submit(&m_messageQueue);
+}
+
 QString DSPEngine::errorMessage()
 {
 	DSPGetErrorMessage cmd;
@@ -174,7 +180,6 @@ void DSPEngine::imbalance(SampleVector::iterator begin, SampleVector::iterator e
 				qMin = it->imag();
 			else if(it->imag() > qMax)
 				qMax = it->imag();
-
 		} else {
 			iMin = it->real();
 			iMax = it->real();
@@ -202,7 +207,7 @@ void DSPEngine::work()
 	size_t samplesDone = 0;
 	bool firstOfBurst = true;
 
-	while((sampleFifo->fill() > 0) && (m_messageQueue.countPending() == 0) && (samplesDone < m_sampleRate)) {
+	while((sampleFifo->fill() > 0) && (m_messageQueue.countPending() == 0) && (samplesDone < m_sampleRate / 2)) {
 		SampleVector::iterator part1begin;
 		SampleVector::iterator part1end;
 		SampleVector::iterator part2begin;
@@ -218,7 +223,7 @@ void DSPEngine::work()
 			if(m_iqImbalanceCorrection)
 				imbalance(part1begin, part1end);
 			// feed data to handlers
-			for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); it++)
+			for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); ++it)
 				(*it)->feed(part1begin, part1end, firstOfBurst);
 			firstOfBurst = false;
 		}
@@ -230,7 +235,7 @@ void DSPEngine::work()
 			if(m_iqImbalanceCorrection)
 				imbalance(part2begin, part2end);
 			// feed data to handlers
-			for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); it++)
+			for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); ++it)
 				(*it)->feed(part2begin, part2end, firstOfBurst);
 			firstOfBurst = false;
 		}
@@ -239,69 +244,6 @@ void DSPEngine::work()
 		sampleFifo->readCommit(count);
 		samplesDone += count;
 	}
-
-#if 0
-	size_t wus;
-	size_t maxWorkUnitSize = 0;
-	size_t samplesDone = 0;
-
-	wus = m_spectrum.workUnitSize();
-	if(wus > maxWorkUnitSize)
-		maxWorkUnitSize = wus;
-	for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); it++) {
-		wus = (*it)->workUnitSize();
-		if(wus > maxWorkUnitSize)
-			maxWorkUnitSize = wus;
-	}
-
-	while((m_sampleFifo.fill() > maxWorkUnitSize) && (m_commandQueue.countPending() == 0) && (samplesDone < m_sampleRate)) {
-		SampleVector::iterator part1begin;
-		SampleVector::iterator part1end;
-		SampleVector::iterator part2begin;
-		SampleVector::iterator part2end;
-
-		size_t count = m_sampleFifo.readBegin(m_sampleFifo.fill(), &part1begin, &part1end, &part2begin, &part2end);
-
-		// first part of FIFO data
-		if(part1begin != part1end) {
-			// correct stuff
-			if(m_settings.dcOffsetCorrection())
-				dcOffset(part1begin, part1end);
-			if(m_settings.iqImbalanceCorrection())
-				imbalance(part1begin, part1end);
-			// feed data to handlers
-			m_spectrum.feed(part1begin, part1end);
-			for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); it++)
-				(*it)->feed(part1begin, part1end);
-		}
-		// second part of FIFO data (used when block wraps around)
-		if(part2begin != part2end) {
-			// correct stuff
-			if(m_settings.dcOffsetCorrection())
-				dcOffset(part2begin, part2end);
-			if(m_settings.iqImbalanceCorrection())
-				imbalance(part2begin, part2end);
-			// feed data to handlers
-			m_spectrum.feed(part2begin, part2end);
-			for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); it++)
-				(*it)->feed(part1begin, part1end);
-		}
-
-		// adjust FIFO pointers
-		m_sampleFifo.readCommit(count);
-		samplesDone += count;
-	}
-
-	// check if the center frequency has changed (has to be responsive)
-	if(m_settings.isModifiedCenterFreq())
-		m_sampleSource->setCenterFrequency(m_settings.centerFreq());
-	// check if decimation has changed (needed to be done here, because to high a sample rate can clog the switch)
-	if(m_settings.isModifiedDecimation()) {
-		m_sampleSource->setDecimation(m_settings.decimation());
-		m_sampleRate = 4000000 / (1 << m_settings.decimation());
-		qDebug("New rate: %d", m_sampleRate);
-	}
-#endif
 }
 
 DSPEngine::State DSPEngine::gotoIdle()
@@ -357,7 +299,11 @@ DSPEngine::State DSPEngine::gotoRunning()
 		return gotoError("Could not start sample source");
 	m_deviceDescription = m_sampleSource->getDeviceDescription();
 
-	m_audioOutput.start(0, 44100);
+	if(!m_audioOutput.start()) {
+		m_sampleSource->stopInput();
+		return gotoError(m_audioOutput.getError());
+	}
+
 	for(SampleSinks::const_iterator it = m_sampleSinks.begin(); it != m_sampleSinks.end(); it++)
 		(*it)->start();
 	m_sampleRate = 0; // make sure, report is sent
@@ -447,7 +393,7 @@ void DSPEngine::handleMessages()
 {
 	Message* message;
 	while((message = m_messageQueue.accept()) != NULL) {
-		qDebug("Message: %s", message->getIdentifier());
+		//qDebug("Message: %s", message->getIdentifier());
 
 		if(DSPPing::match(message)) {
 			message->completed(m_state);
@@ -465,16 +411,16 @@ void DSPEngine::handleMessages()
 			m_state = gotoIdle();
 			message->completed(m_state);
 		} else if(DSPGetDeviceDescription::match(message)) {
-			((DSPGetDeviceDescription*)message)->setDeviceDescription(m_deviceDescription);
+			DSPGetDeviceDescription::cast(message)->setDeviceDescription(m_deviceDescription);
 			message->completed();
 		} else if(DSPGetErrorMessage::match(message)) {
 			((DSPGetErrorMessage*)message)->setErrorMessage(m_errorMessage);
 			message->completed();
 		} else if(DSPSetSource::match(message)) {
-			handleSetSource(((DSPSetSource*)message)->getSampleSource());
+			handleSetSource(DSPSetSource::cast(message)->getSampleSource());
 			message->completed();
 		} else if(DSPAddSink::match(message)) {
-			SampleSink* sink = ((DSPAddSink*)message)->getSampleSink();
+			SampleSink* sink = DSPAddSink::cast(message)->getSampleSink();
 			if(m_state == StRunning) {
 				DSPSignalNotification* signal = DSPSignalNotification::create(m_sampleRate, 0);
 				signal->submit(&m_messageQueue, sink);
@@ -489,13 +435,16 @@ void DSPEngine::handleMessages()
 			m_sampleSinks.remove(sink);
 			message->completed();
 		} else if(DSPAddAudioSource::match(message)) {
-			m_audioOutput.addFifo(((DSPAddAudioSource*)message)->getAudioFifo());
+			m_audioOutput.addFifo(DSPAddAudioSource::cast(message)->getAudioFifo());
 			message->completed();
 		} else if(DSPRemoveAudioSource::match(message)) {
 			m_audioOutput.removeFifo(((DSPAddAudioSource*)message)->getAudioFifo());
 			message->completed();
+		} else if(DSPConfigureAudioOutput::match(message)) {
+			DSPConfigureAudioOutput* conf = DSPConfigureAudioOutput::cast(message);
+			m_audioOutput.configure(conf->getAudioOutputDevice(), conf->getAudioOutputRate());
 		} else if(DSPConfigureCorrection::match(message)) {
-			DSPConfigureCorrection* conf = (DSPConfigureCorrection*)message;
+			DSPConfigureCorrection* conf = DSPConfigureCorrection::cast(message);
 			m_iqImbalanceCorrection = conf->getIQImbalanceCorrection();
 			if(m_dcOffsetCorrection != conf->getDCOffsetCorrection()) {
 				m_dcOffsetCorrection = conf->getDCOffsetCorrection();
diff --git a/sdrbase/dsp/fftwengine.cpp b/sdrbase/dsp/fftwengine.cpp
index 76b189e..f5062fb 100644
--- a/sdrbase/dsp/fftwengine.cpp
+++ b/sdrbase/dsp/fftwengine.cpp
@@ -21,6 +21,7 @@ void FFTWEngine::configure(int n, bool inverse)
 		}
 	}
 
+	m_globalPlanMutex.lock();
 	m_currentPlan = new Plan;
 	m_currentPlan->n = n;
 	m_currentPlan->inverse = inverse;
@@ -28,7 +29,6 @@ void FFTWEngine::configure(int n, bool inverse)
 	m_currentPlan->out = (fftwf_complex*)fftwf_malloc(sizeof(fftwf_complex) * n);
 	QTime t;
 	t.start();
-	m_globalPlanMutex.lock();
 	m_currentPlan->plan = fftwf_plan_dft_1d(n, m_currentPlan->in, m_currentPlan->out, inverse ? FFTW_BACKWARD : FFTW_FORWARD, FFTW_PATIENT);
 	m_globalPlanMutex.unlock();
 	qDebug("FFT: creating FFTW plan (n=%d,%s) took %dms", n, inverse ? "inverse" : "forward", t.elapsed());
diff --git a/sdrbase/dsp/nco.cpp b/sdrbase/dsp/nco.cpp
index 1143cf8..1982750 100644
--- a/sdrbase/dsp/nco.cpp
+++ b/sdrbase/dsp/nco.cpp
@@ -30,7 +30,7 @@ void NCO::initTable()
 		return;
 
 	for(int i = 0; i < TableSize; i++)
-		m_table[i] = cos((2.0 * M_PI * i) / TableSize);
+		m_table[i] = cos((2.0 * M_PI * (Real)i) / ((Real)TableSize));
 
 	m_tableInitialized = true;
 }
@@ -43,8 +43,15 @@ NCO::NCO()
 
 void NCO::setFreq(Real freq, Real sampleRate)
 {
-	m_phaseIncrement = (freq * TableSize) / sampleRate;
-	qDebug("NCO phase inc %d", m_phaseIncrement);
+	if(sampleRate > 0) {
+		m_phaseIncrement = (freq * TableSize) / sampleRate;
+		if(m_phaseIncrement != 0)
+			qDebug("NCO phase inc %d (period %f)", m_phaseIncrement, (Real)TableSize / (Real)m_phaseIncrement);
+		else qDebug("NCO phase inc %d (period oo)", m_phaseIncrement);
+	} else {
+		qDebug("cannot calculate NCO phase increment since samplerate is 0");
+		m_phaseIncrement = 1;
+	}
 }
 
 float NCO::next()
@@ -66,5 +73,7 @@ Complex NCO::nextIQ()
 	while(m_phase < 0)
 		m_phase += TableSize;
 
-	return Complex(m_table[m_phase], -m_table[(m_phase + TableSize / 4) % TableSize]);
+	int idxQuad = (m_phase + (TableSize / 4) + (TableSize / 2)) % TableSize;
+
+	return Complex(m_table[m_phase], m_table[idxQuad]);
 }
diff --git a/sdrbase/dsp/pidcontroller.cpp b/sdrbase/dsp/pidcontroller.cpp
index 8b015f6..a5d5356 100644
--- a/sdrbase/dsp/pidcontroller.cpp
+++ b/sdrbase/dsp/pidcontroller.cpp
@@ -1,4 +1,4 @@
-#include "pidcontroller.h"
+#include "dsp/pidcontroller.h"
 
 PIDController::PIDController() :
 	m_p(0.0),
diff --git a/sdrbase/dsp/pidcontroller.h b/sdrbase/dsp/pidcontroller.h
deleted file mode 100644
index 7b96793..0000000
--- a/sdrbase/dsp/pidcontroller.h
+++ /dev/null
@@ -1,28 +0,0 @@
-#ifndef INCLUDE_PIDCONTROLLER_H
-#define INCLUDE_PIDCONTROLLER_H
-
-#include "dsp/dsptypes.h"
-
-class PIDController {
-private:
-	Real m_p;
-	Real m_i;
-	Real m_d;
-	Real m_int;
-	Real m_diff;
-
-public:
-	PIDController();
-
-	void setup(Real p, Real i, Real d);
-
-	Real feed(Real v)
-	{
-		m_int += v * m_i;
-		Real d = m_d * (m_diff - v);
-		m_diff = v;
-		return (v * m_p) + m_int + d;
-	}
-};
-
-#endif // INCLUDE_PIDCONTROLLER_H
diff --git a/sdrbase/dsp/samplefifo.cpp b/sdrbase/dsp/samplefifo.cpp
index caa4969..e9d29b8 100644
--- a/sdrbase/dsp/samplefifo.cpp
+++ b/sdrbase/dsp/samplefifo.cpp
@@ -64,17 +64,21 @@ bool SampleFifo::setSize(int size)
 {
 	create(size);
 
-	return m_data.size() == (uint)size;
+	return m_size == (uint)size;
 }
 
 uint SampleFifo::write(const quint8* data, uint count)
 {
+	return write(SampleVector::const_iterator((Sample*)data), SampleVector::const_iterator((Sample*)(data + count)));
+#if 0
 	QMutexLocker mutexLocker(&m_mutex);
 	uint total;
 	uint remaining;
 	uint len;
 	const Sample* begin = (const Sample*)data;
-	count /= 4;
+	count /= sizeof(Sample);
+
+	//qDebug("write pre count %d %u", count, m_fill);
 
 	total = MIN(count, m_size - m_fill);
 	if(total < count) {
@@ -96,6 +100,7 @@ uint SampleFifo::write(const quint8* data, uint count)
 	remaining = total;
 	while(remaining > 0) {
 		len = MIN(remaining, m_size - m_tail);
+		//qDebug("write remaining %u, len %u", remaining, len);
 		std::copy(begin, begin + len, m_data.begin() + m_tail);
 		m_tail += len;
 		m_tail %= m_size;
@@ -104,10 +109,13 @@ uint SampleFifo::write(const quint8* data, uint count)
 		remaining -= len;
 	}
 
+	//qDebug("write post count %d %u [%u;%u]", count, m_fill, m_head, m_tail);
+
 	if(m_fill > 0)
 		emit dataReady();
 
 	return total;
+#endif
 }
 
 uint SampleFifo::write(SampleVector::const_iterator begin, SampleVector::const_iterator end)
@@ -139,8 +147,7 @@ uint SampleFifo::write(SampleVector::const_iterator begin, SampleVector::const_i
 	while(remaining > 0) {
 		len = MIN(remaining, m_size - m_tail);
 		std::copy(begin, begin + len, m_data.begin() + m_tail);
-		m_tail += len;
-		m_tail %= m_size;
+		m_tail = (m_tail + len) % m_size;
 		m_fill += len;
 		begin += len;
 		remaining -= len;
@@ -151,7 +158,7 @@ uint SampleFifo::write(SampleVector::const_iterator begin, SampleVector::const_i
 
 	return total;
 }
-
+/*
 uint SampleFifo::read(SampleVector::iterator begin, SampleVector::iterator end)
 {
 	QMutexLocker mutexLocker(&m_mutex);
@@ -177,13 +184,14 @@ uint SampleFifo::read(SampleVector::iterator begin, SampleVector::iterator end)
 
 	return total;
 }
-
+*/
 uint SampleFifo::readBegin(uint count,
 	SampleVector::iterator* part1Begin, SampleVector::iterator* part1End,
 	SampleVector::iterator* part2Begin, SampleVector::iterator* part2End)
 {
 	QMutexLocker mutexLocker(&m_mutex);
 	uint total;
+	uint done = 0;
 	uint remaining;
 	uint len;
 	uint head = m_head;
@@ -196,10 +204,10 @@ uint SampleFifo::readBegin(uint count,
 	if(remaining > 0) {
 		len = MIN(remaining, m_size - head);
 		*part1Begin = m_data.begin() + head;
-		*part1End = m_data.begin() + head + len;
-		head += len;
-		head %= m_size;
+		*part1End = *part1Begin + len;
+		head = (head + len) % m_size;
 		remaining -= len;
+		done += len;
 	} else {
 		*part1Begin = m_data.end();
 		*part1End = m_data.end();
@@ -207,13 +215,14 @@ uint SampleFifo::readBegin(uint count,
 	if(remaining > 0) {
 		len = MIN(remaining, m_size - head);
 		*part2Begin = m_data.begin() + head;
-		*part2End = m_data.begin() + head + len;
+		*part2End = *part2Begin + len;
+		done += len;
 	} else {
 		*part2Begin = m_data.end();
 		*part2End = m_data.end();
 	}
 
-	return total;
+	return done;
 }
 
 uint SampleFifo::readCommit(uint count)
diff --git a/sdrbase/dsp/spectrumvis.cpp b/sdrbase/dsp/spectrumvis.cpp
index 01c7dbe..627a093 100644
--- a/sdrbase/dsp/spectrumvis.cpp
+++ b/sdrbase/dsp/spectrumvis.cpp
@@ -3,7 +3,7 @@
 #include "dsp/dspcommands.h"
 #include "util/messagequeue.h"
 
-#define MAX_FFT_SIZE 4096
+#define MAX_FFT_SIZE 8192
 
 #ifdef _WIN32
 double log2f(double n)
diff --git a/sdrbase/dsp/threadedsamplesink.cpp b/sdrbase/dsp/threadedsamplesink.cpp
index ad157b9..313ed24 100644
--- a/sdrbase/dsp/threadedsamplesink.cpp
+++ b/sdrbase/dsp/threadedsamplesink.cpp
@@ -15,7 +15,7 @@ ThreadedSampleSink::ThreadedSampleSink(SampleSink* sampleSink) :
 
 	m_sampleFifo.moveToThread(m_thread);
 	connect(&m_sampleFifo, SIGNAL(dataReady()), this, SLOT(handleData()));
-	m_sampleFifo.setSize(262144);
+	m_sampleFifo.setSize(128 * 1024);
 
 	sampleSink->moveToThread(m_thread);
 }
@@ -55,8 +55,11 @@ bool ThreadedSampleSink::handleMessage(Message* cmd)
 void ThreadedSampleSink::handleData()
 {
 	bool firstOfBurst = true;
+	QTime time;
 
-	while((m_sampleFifo.fill() > 0) && (m_messageQueue.countPending() == 0)) {
+	time.start();
+
+	while((m_sampleFifo.fill() > 0) && (m_messageQueue.countPending() == 0) && (time.elapsed() < 250)) {
 		SampleVector::iterator part1begin;
 		SampleVector::iterator part1end;
 		SampleVector::iterator part2begin;
@@ -64,19 +67,19 @@ void ThreadedSampleSink::handleData()
 
 		size_t count = m_sampleFifo.readBegin(m_sampleFifo.fill(), &part1begin, &part1end, &part2begin, &part2end);
 
-		// first part of FIFO data
-		if(part1begin != part1end) {
-			// handle data
-			if(m_sampleSink != NULL)
-				m_sampleSink->feed(part1begin, part1end, firstOfBurst);
-			firstOfBurst = false;
-		}
-		// second part of FIFO data (used when block wraps around)
-		if(part2begin != part2end) {
-			// handle data
-			if(m_sampleSink != NULL)
+		if(m_sampleSink != NULL) {
+			// first part of FIFO data
+			if(part1begin != part1end) {
+				// handle data
 				m_sampleSink->feed(part1begin, part1end, firstOfBurst);
-			firstOfBurst = false;
+				firstOfBurst = false;
+			}
+			// second part of FIFO data (used when block wraps around)
+			if(part2begin != part2end) {
+				// handle data
+				m_sampleSink->feed(part2begin, part2end, firstOfBurst);
+				firstOfBurst = false;
+			}
 		}
 
 		// adjust FIFO pointers
@@ -88,7 +91,7 @@ void ThreadedSampleSink::handleMessages()
 {
 	Message* message;
 	while((message = m_messageQueue.accept()) != NULL) {
-		qDebug("CMD: %s", message->getIdentifier());
+		//qDebug("CMD: %s", message->getIdentifier());
 		if(m_sampleSink != NULL) {
 			if(!m_sampleSink->handleMessage(message))
 				message->completed();
diff --git a/sdrbase/gui/glspectrumgui.cpp b/sdrbase/gui/glspectrumgui.cpp
index 1fbaaf2..6231e8d 100644
--- a/sdrbase/gui/glspectrumgui.cpp
+++ b/sdrbase/gui/glspectrumgui.cpp
@@ -112,7 +112,7 @@ bool GLSpectrumGUI::deserialize(const QByteArray& data)
 void GLSpectrumGUI::applySettings()
 {
 	ui->fftWindow->setCurrentIndex(m_fftWindow);
-	for(int i = 0; i < 6; i++) {
+	for(int i = 0; i < 7; i++) {
 		if(m_fftSize == (1 << (i + 7))) {
 			ui->fftSize->setCurrentIndex(i);
 			break;
diff --git a/sdrbase/gui/glspectrumgui.ui b/sdrbase/gui/glspectrumgui.ui
index 2a9babe..a738255 100644
--- a/sdrbase/gui/glspectrumgui.ui
+++ b/sdrbase/gui/glspectrumgui.ui
@@ -14,7 +14,16 @@
    <string>Oscilloscope</string>
   </property>
   <layout class="QGridLayout" name="gridLayout" columnstretch="1,1,1,1">
-   <property name="margin">
+   <property name="leftMargin">
+    <number>2</number>
+   </property>
+   <property name="topMargin">
+    <number>2</number>
+   </property>
+   <property name="rightMargin">
+    <number>2</number>
+   </property>
+   <property name="bottomMargin">
     <number>2</number>
    </property>
    <property name="spacing">
@@ -162,6 +171,11 @@
        <string>4096</string>
       </property>
      </item>
+     <item>
+      <property name="text">
+       <string>8192</string>
+      </property>
+     </item>
     </widget>
    </item>
    <item row="1" column="2">
diff --git a/sdrbase/gui/preferencesdialog.cpp b/sdrbase/gui/preferencesdialog.cpp
index 077ef45..5394150 100644
--- a/sdrbase/gui/preferencesdialog.cpp
+++ b/sdrbase/gui/preferencesdialog.cpp
@@ -1,47 +1,61 @@
 #include <QTreeWidgetItem>
+#include <QAudioDeviceInfo>
 #include "gui/preferencesdialog.h"
 #include "ui_preferencesdialog.h"
-#include "audio/audiodeviceinfo.h"
+#include "settings/preferences.h"
 
-PreferencesDialog::PreferencesDialog(AudioDeviceInfo* audioDeviceInfo, QWidget* parent) :
+PreferencesDialog::PreferencesDialog(Preferences* preferences, QWidget* parent) :
 	QDialog(parent),
 	ui(new Ui::PreferencesDialog),
-	m_audioDeviceInfo(audioDeviceInfo)
+	m_preferences(preferences)
 {
 	ui->setupUi(this);
 
-	const AudioDeviceInfo::Devices& devices = audioDeviceInfo->getDevices();
-
-	QTreeWidgetItem* api;
 	QStringList sl;
-	sl.append(tr("Default (use first suitable device)"));
-	api = new QTreeWidgetItem(ui->audioTree, sl, ATDefault);
-	api->setFirstColumnSpanned(true);
-	for(AudioDeviceInfo::Devices::const_iterator it = devices.begin(); it != devices.end(); ++it) {
-		int apiIndex;
-		sl.clear();
+	bool found;
 
-		for(apiIndex = 0; apiIndex < ui->audioTree->topLevelItemCount(); ++apiIndex) {
-			if(ui->audioTree->topLevelItem(apiIndex)->text(0) == it->api)
-				break;
-		}
-		if(apiIndex >= ui->audioTree->topLevelItemCount()) {
-			sl.append(it->api);
-			api = new QTreeWidgetItem(ui->audioTree, sl, ATInterface);
-			api->setExpanded(true);
-			api->setFirstColumnSpanned(true);
-			sl.clear();
-		} else {
-			api = ui->audioTree->topLevelItem(apiIndex);
-		}
+	QList<QAudioDeviceInfo> devices = QAudioDeviceInfo::availableDevices(QAudio::AudioOutput);
 
-		sl.append(it->name);
-		new QTreeWidgetItem(api, sl, ATDevice);
+	sl.clear();
+	sl.append(tr("Default output device (use first suitable)"));
+	QTreeWidgetItem* dev = new QTreeWidgetItem(ui->audioTree, sl);
+	dev->setFirstColumnSpanned(true);
+	dev->setData(0, Qt::UserRole, "");
+	for(QList<QAudioDeviceInfo>::ConstIterator it = devices.begin(); it != devices.end(); ++it) {
+		sl.clear();
+		sl.append(it->deviceName());
+		QTreeWidgetItem* dev = new QTreeWidgetItem(ui->audioTree, sl);
+		dev->setFirstColumnSpanned(true);
+		dev->setData(0, Qt::UserRole, it->deviceName());
 	}
-	if(ui->audioTree->currentItem() == NULL)
+	found = false;
+	for(int i = 0; i < ui->audioTree->topLevelItemCount(); ++i) {
+		if(ui->audioTree->topLevelItem(i)->data(0, Qt::UserRole).toString() == m_preferences->getAudioOutput()) {
+			ui->audioTree->setCurrentItem(ui->audioTree->topLevelItem(i));
+			found = true;
+			break;
+		}
+	}
+	if(!found)
 		ui->audioTree->setCurrentItem(ui->audioTree->topLevelItem(0));
 
-	ui->tabWidget->setCurrentIndex(0);
+	ui->audioRate->addItem(tr("48000 Hz"), 48000);
+	ui->audioRate->addItem(tr("44100 Hz"), 44100);
+	ui->audioRate->addItem(tr("24000 Hz"), 24000);
+	ui->audioRate->addItem(tr("22050 Hz"), 22050);
+	found = false;
+	for(int i = 0; i < ui->audioRate->count(); ++i) {
+		if(ui->audioRate->itemData(i).toInt() == m_preferences->getAudioOutputRate()) {
+			ui->audioRate->setCurrentIndex(i);
+			found = true;
+			break;
+		}
+	}
+	if(!found)
+		ui->audioRate->setCurrentIndex(1);
+
+	ui->stackedWidget->setCurrentIndex(0);
+	ui->configTree->setCurrentItem(ui->configTree->topLevelItem(0));
 }
 
 PreferencesDialog::~PreferencesDialog()
@@ -51,5 +65,10 @@ PreferencesDialog::~PreferencesDialog()
 
 void PreferencesDialog::accept()
 {
+	if(ui->audioTree->currentItem() != NULL)
+		m_preferences->setAudioOutput(ui->audioTree->currentItem()->data(0, Qt::UserRole).toString());
+	else m_preferences->setAudioOutput(QString());
+	m_preferences->setAudioOutputRate(ui->audioRate->itemData(ui->audioRate->currentIndex()).toInt());
+
 	QDialog::accept();
 }
diff --git a/sdrbase/gui/preferencesdialog.ui b/sdrbase/gui/preferencesdialog.ui
index 0545931..f98a149 100644
--- a/sdrbase/gui/preferencesdialog.ui
+++ b/sdrbase/gui/preferencesdialog.ui
@@ -6,42 +6,55 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>400</width>
-    <height>300</height>
+    <width>454</width>
+    <height>435</height>
    </rect>
   </property>
   <property name="windowTitle">
    <string>Dialog</string>
   </property>
-  <layout class="QVBoxLayout" name="verticalLayout">
-   <item>
-    <widget class="QTabWidget" name="tabWidget">
-     <property name="currentIndex">
-      <number>0</number>
+  <layout class="QGridLayout" name="gridLayout" columnstretch="1,3">
+   <item row="0" column="0">
+    <widget class="QTreeWidget" name="configTree">
+     <property name="rootIsDecorated">
+      <bool>false</bool>
      </property>
-     <widget class="QWidget" name="tab">
-      <attribute name="title">
-       <string>Receiver Hardware</string>
-      </attribute>
-      <layout class="QVBoxLayout" name="verticalLayout_2">
-       <item>
-        <widget class="QTreeWidget" name="treeWidget">
-         <column>
-          <property name="text">
-           <string notr="true">1</string>
-          </property>
-         </column>
-        </widget>
-       </item>
-      </layout>
-     </widget>
-     <widget class="QWidget" name="tab_2">
-      <attribute name="title">
+     <attribute name="headerVisible">
+      <bool>false</bool>
+     </attribute>
+     <column>
+      <property name="text">
+       <string notr="true">Section</string>
+      </property>
+     </column>
+     <item>
+      <property name="text">
        <string>Audio Output</string>
-      </attribute>
-      <layout class="QVBoxLayout" name="verticalLayout_3">
+      </property>
+      <property name="flags">
+       <set>ItemIsSelectable|ItemIsEnabled</set>
+      </property>
+     </item>
+    </widget>
+   </item>
+   <item row="0" column="1">
+    <widget class="QStackedWidget" name="stackedWidget">
+     <property name="sizePolicy">
+      <sizepolicy hsizetype="Expanding" vsizetype="Preferred">
+       <horstretch>0</horstretch>
+       <verstretch>0</verstretch>
+      </sizepolicy>
+     </property>
+     <property name="frameShape">
+      <enum>QFrame::StyledPanel</enum>
+     </property>
+     <widget class="QWidget" name="page">
+      <layout class="QVBoxLayout" name="verticalLayout">
        <item>
         <widget class="QTreeWidget" name="audioTree">
+         <property name="rootIsDecorated">
+          <bool>false</bool>
+         </property>
          <column>
           <property name="text">
            <string notr="true">Device</string>
@@ -49,11 +62,49 @@
          </column>
         </widget>
        </item>
+       <item>
+        <layout class="QHBoxLayout" name="horizontalLayout">
+         <item>
+          <widget class="QLabel" name="label">
+           <property name="text">
+            <string>Sample rate</string>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <widget class="QComboBox" name="audioRate">
+           <property name="sizePolicy">
+            <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
+             <horstretch>0</horstretch>
+             <verstretch>0</verstretch>
+            </sizepolicy>
+           </property>
+           <property name="sizeAdjustPolicy">
+            <enum>QComboBox::AdjustToContents</enum>
+           </property>
+          </widget>
+         </item>
+         <item>
+          <spacer name="horizontalSpacer">
+           <property name="orientation">
+            <enum>Qt::Horizontal</enum>
+           </property>
+           <property name="sizeHint" stdset="0">
+            <size>
+             <width>40</width>
+             <height>20</height>
+            </size>
+           </property>
+          </spacer>
+         </item>
+        </layout>
+       </item>
       </layout>
      </widget>
+     <widget class="QWidget" name="page_2"/>
     </widget>
    </item>
-   <item>
+   <item row="1" column="0" colspan="2">
     <widget class="QDialogButtonBox" name="buttonBox">
      <property name="orientation">
       <enum>Qt::Horizontal</enum>
@@ -67,9 +118,6 @@
  </widget>
  <tabstops>
   <tabstop>buttonBox</tabstop>
-  <tabstop>tabWidget</tabstop>
-  <tabstop>treeWidget</tabstop>
-  <tabstop>audioTree</tabstop>
  </tabstops>
  <resources/>
  <connections>
diff --git a/sdrbase/gui/scopewindow.cpp b/sdrbase/gui/scopewindow.cpp
index 2f6200f..486242a 100644
--- a/sdrbase/gui/scopewindow.cpp
+++ b/sdrbase/gui/scopewindow.cpp
@@ -19,14 +19,13 @@
 #include "ui_scopewindow.h"
 #include "util/simpleserializer.h"
 
-ScopeWindow::ScopeWindow(DSPEngine* dspEngine, QWidget* parent) :
+ScopeWindow::ScopeWindow(QWidget* parent) :
 	QWidget(parent),
 	ui(new Ui::ScopeWindow),
 	m_sampleRate(0),
 	m_timeBase(1)
 {
 	ui->setupUi(this);
-	ui->scope->setDSPEngine(dspEngine);
 }
 
 ScopeWindow::~ScopeWindow()
@@ -34,6 +33,11 @@ ScopeWindow::~ScopeWindow()
 	delete ui;
 }
 
+void ScopeWindow::setDSPEngine(DSPEngine* dspEngine)
+{
+	ui->scope->setDSPEngine(dspEngine);
+}
+
 void ScopeWindow::setSampleRate(int sampleRate)
 {
 	m_sampleRate = sampleRate;
diff --git a/sdrbase/mainwindow.cpp b/sdrbase/mainwindow.cpp
index 9cbfb0f..904b3c9 100644
--- a/sdrbase/mainwindow.cpp
+++ b/sdrbase/mainwindow.cpp
@@ -20,7 +20,6 @@
 #include <QLabel>
 #include "mainwindow.h"
 #include "ui_mainwindow.h"
-#include "audio/audiodeviceinfo.h"
 #include "gui/indicator.h"
 #include "gui/presetitem.h"
 #include "gui/scopewindow.h"
@@ -39,7 +38,6 @@
 MainWindow::MainWindow(QWidget* parent) :
 	QMainWindow(parent),
 	ui(new Ui::MainWindow),
-	m_audioDeviceInfo(new AudioDeviceInfo),
 	m_messageQueue(new MessageQueue),
 	m_settings(),
 	m_dspEngine(new DSPEngine(m_messageQueue)),
@@ -196,6 +194,8 @@ void MainWindow::loadSettings(const Preset* preset)
 
 	m_pluginManager->loadSettings(preset);
 
+	m_dspEngine->configureAudioOutput(m_settings.getPreferences()->getAudioOutput(), m_settings.getPreferences()->getAudioOutputRate());
+
 	// has to be last step
 	restoreState(preset->getLayout());
 }
@@ -306,12 +306,12 @@ void MainWindow::handleMessages()
 {
 	Message* message;
 	while((message = m_messageQueue->accept()) != NULL) {
-		qDebug("Message: %s", message->getIdentifier());
+		//qDebug("Message: %s", message->getIdentifier());
 		if(DSPEngineReport::match(message)) {
-			DSPEngineReport* rep = (DSPEngineReport*)message;
+			DSPEngineReport* rep = DSPEngineReport::cast(message);
 			m_sampleRate = rep->getSampleRate();
 			m_centerFrequency = rep->getCenterFrequency();
-			qDebug("SampleRate:%d, CenterFrequency:%llu", rep->getSampleRate(), rep->getCenterFrequency());
+			//qDebug("SampleRate:%d, CenterFrequency:%llu", rep->getSampleRate(), rep->getCenterFrequency());
 			updateCenterFreqDisplay();
 			updateSampleRate();
 			message->completed();
@@ -332,6 +332,7 @@ void MainWindow::updateStatus()
 				m_engineRunning->setColor(Qt::gray);
 				m_engineError->setColor(Qt::gray);
 				statusBar()->clearMessage();
+				updateEnables(false);
 				break;
 
 			case DSPEngine::StIdle:
@@ -339,6 +340,7 @@ void MainWindow::updateStatus()
 				m_engineRunning->setColor(Qt::gray);
 				m_engineError->setColor(Qt::gray);
 				statusBar()->clearMessage();
+				updateEnables(false);
 				if(m_startOsmoSDRUpdateAfterStop)
 					on_actionOsmoSDR_Firmware_Upgrade_triggered();
 				break;
@@ -348,6 +350,7 @@ void MainWindow::updateStatus()
 				m_engineRunning->setColor(Qt::green);
 				m_engineError->setColor(Qt::gray);
 				statusBar()->showMessage(tr("Sampling from %1").arg(m_dspEngine->deviceDescription()));
+				updateEnables(true);
 				break;
 
 			case DSPEngine::StError:
@@ -355,6 +358,8 @@ void MainWindow::updateStatus()
 				m_engineRunning->setColor(Qt::gray);
 				m_engineError->setColor(Qt::red);
 				statusBar()->showMessage(tr("Error: %1").arg(m_dspEngine->errorMessage()));
+				QMessageBox::critical(this, tr("Engine Error"), tr("%1").arg(m_dspEngine->errorMessage()), QMessageBox::Ok);
+				updateEnables(false);
 				if(m_startOsmoSDRUpdateAfterStop)
 					on_actionOsmoSDR_Firmware_Upgrade_triggered();
 				break;
@@ -363,6 +368,15 @@ void MainWindow::updateStatus()
 	}
 }
 
+void MainWindow::updateEnables(bool running)
+{
+	if(running) {
+		ui->action_Preferences->setEnabled(false);
+	} else {
+		ui->action_Preferences->setEnabled(true);
+	}
+}
+
 void MainWindow::scopeWindowDestroyed()
 {
 	ui->action_Oscilloscope->setChecked(false);
@@ -490,7 +504,9 @@ void MainWindow::on_action_Oscilloscope_triggered()
 
 	QDockWidget* dock = new QDockWidget(tr("Signalscope"), this);
 	dock->setObjectName(QString::fromUtf8("scopeDock"));
-	m_scopeWindow = new ScopeWindow(m_dspEngine);
+
+	m_scopeWindow = new ScopeWindow();
+	m_scopeWindow->setDSPEngine(m_dspEngine);
 	connect(m_scopeWindow, SIGNAL(destroyed()), this, SLOT(scopeWindowDestroyed()));
 	m_scopeWindow->setSampleRate(m_sampleRate);
 	dock->setWidget(m_scopeWindow);
@@ -509,9 +525,11 @@ void MainWindow::on_action_Loaded_Plugins_triggered()
 
 void MainWindow::on_action_Preferences_triggered()
 {
-	PreferencesDialog preferencesDialog(m_audioDeviceInfo, this);
+	PreferencesDialog preferencesDialog(m_settings.getPreferences(), this);
 
-	preferencesDialog.exec();
+	if(preferencesDialog.exec() == QDialog::Accepted) {
+		m_dspEngine->configureAudioOutput(m_settings.getPreferences()->getAudioOutput(), m_settings.getPreferences()->getAudioOutputRate());
+	}
 }
 
 void MainWindow::on_sampleSource_currentIndexChanged(int index)
diff --git a/sdrbase/plugin/pluginmanager.cpp b/sdrbase/plugin/pluginmanager.cpp
index 3338c01..325fb8b 100644
--- a/sdrbase/plugin/pluginmanager.cpp
+++ b/sdrbase/plugin/pluginmanager.cpp
@@ -72,7 +72,7 @@ void PluginManager::registerSampleSource(const QString& sourceName, PluginInterf
 
 void PluginManager::loadSettings(const Preset* preset)
 {
-	qDebug("-------- [%s | %s] --------", qPrintable(preset->getGroup()), qPrintable(preset->getDescription()));
+	//qDebug("-------- [%s | %s] --------", qPrintable(preset->getGroup()), qPrintable(preset->getDescription()));
 
 	// copy currently open channels and clear list
 	ChannelInstanceRegistrations openChannels = m_channelInstanceRegistrations;
@@ -83,7 +83,7 @@ void PluginManager::loadSettings(const Preset* preset)
 		ChannelInstanceRegistration reg;
 		// if we have one instance available already, use it
 		for(int i = 0; i < openChannels.count(); i++) {
-			qDebug("compare [%s] vs [%s]", qPrintable(openChannels[i].m_channelName), qPrintable(channelConfig.m_channel));
+			//qDebug("compare [%s] vs [%s]", qPrintable(openChannels[i].m_channelName), qPrintable(channelConfig.m_channel));
 			if(openChannels[i].m_channelName == channelConfig.m_channel) {
 				qDebug("channel [%s] found", qPrintable(openChannels[i].m_channelName));
 				reg = openChannels.takeAt(i);
@@ -235,7 +235,7 @@ int PluginManager::selectSampleSource(const QString& source)
 
 	qDebug("finding sample source [%s]", qPrintable(source));
 	for(int i = 0; i < m_sampleSourceDevices.count(); i++) {
-		qDebug("*** %s vs %s", qPrintable(m_sampleSourceDevices[i].m_sourceName), qPrintable(source));
+		//qDebug("*** %s vs %s", qPrintable(m_sampleSourceDevices[i].m_sourceName), qPrintable(source));
 		if(m_sampleSourceDevices[i].m_sourceName == source) {
 			index = i;
 			break;
diff --git a/sdrbase/settings/preferences.cpp b/sdrbase/settings/preferences.cpp
index c649cda..e1391fb 100644
--- a/sdrbase/settings/preferences.cpp
+++ b/sdrbase/settings/preferences.cpp
@@ -8,19 +8,15 @@ Preferences::Preferences()
 
 void Preferences::resetToDefaults()
 {
-	m_sourceType.clear();
-	m_sourceDevice.clear();
-	m_audioType.clear();
-	m_audioDevice.clear();
+	m_audioOutput.clear();
+	m_audioOutputRate = 44100;
 }
 
 QByteArray Preferences::serialize() const
 {
 	SimpleSerializer s(1);
-	s.writeString(1, m_sourceType);
-	s.writeString(2, m_sourceDevice);
-	s.writeString(3, m_audioType);
-	s.writeString(4, m_audioDevice);
+	s.writeString(1, m_audioOutput);
+	s.writeU32(2, m_audioOutputRate);
 	return s.final();
 }
 
@@ -34,10 +30,10 @@ bool Preferences::deserialize(const QByteArray& data)
 	}
 
 	if(d.getVersion() == 1) {
-		d.readString(1, &m_sourceType);
-		d.readString(2, &m_sourceDevice);
-		d.readString(3, &m_audioType);
-		d.readString(4, &m_audioDevice);
+		d.readString(1, &m_audioOutput);
+		quint32 tmp;
+		d.readU32(2, &tmp, 44100);
+		m_audioOutputRate = tmp;
 		return true;
 	} else {
 		resetToDefaults();
diff --git a/sdrbase/util/message.cpp b/sdrbase/util/message.cpp
index 8431ca7..1ddf7af 100644
--- a/sdrbase/util/message.cpp
+++ b/sdrbase/util/message.cpp
@@ -29,6 +29,8 @@ const char* Message::getIdentifier() const
 
 bool Message::matchIdentifier(const char* identifier) const
 {
+	// Warning: this compares POINTERS - make sure, that each message has a unique name
+	// otherwise the linker might "optimize" stuff
 	return m_identifier == identifier;
 }