engine.cpp Example File

spectrum/app/engine.cpp
/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
**   * Redistributions of source code must retain the above copyright
**     notice, this list of conditions and the following disclaimer.
**   * Redistributions in binary form must reproduce the above copyright
**     notice, this list of conditions and the following disclaimer in
**     the documentation and/or other materials provided with the
**     distribution.
**   * Neither the name of The Qt Company Ltd nor the names of its
**     contributors may be used to endorse or promote products derived
**     from this software without specific prior written permission.
**
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "engine.h"
#include "tonegenerator.h"
#include "utils.h"

#include <math.h>

#include <QAudioInput>
#include <QAudioOutput>
#include <QCoreApplication>
#include <QDebug>
#include <QFile>
#include <QMetaObject>
#include <QSet>
#include <QThread>

//-----------------------------------------------------------------------------
// Constants
//-----------------------------------------------------------------------------

const qint64 BufferDurationUs       = 10 * 1000000;
const int    NotifyIntervalMs       = 100;

// Size of the level calculation window in microseconds
const int    LevelWindowUs          = 0.1 * 1000000;

//-----------------------------------------------------------------------------
// Constructor and destructor
//-----------------------------------------------------------------------------

Engine::Engine(QObject *parent)
    :   QObject(parent)
    ,   m_mode(QAudio::AudioInput)
    ,   m_state(QAudio::StoppedState)
    ,   m_generateTone(false)
    ,   m_file(0)
    ,   m_analysisFile(0)
    ,   m_availableAudioInputDevices
            (QAudioDeviceInfo::availableDevices(QAudio::AudioInput))
    ,   m_audioInputDevice(QAudioDeviceInfo::defaultInputDevice())
    ,   m_audioInput(0)
    ,   m_audioInputIODevice(0)
    ,   m_recordPosition(0)
    ,   m_availableAudioOutputDevices
            (QAudioDeviceInfo::availableDevices(QAudio::AudioOutput))
    ,   m_audioOutputDevice(QAudioDeviceInfo::defaultOutputDevice())
    ,   m_audioOutput(0)
    ,   m_playPosition(0)
    ,   m_bufferPosition(0)
    ,   m_bufferLength(0)
    ,   m_dataLength(0)
    ,   m_levelBufferLength(0)
    ,   m_rmsLevel(0.0)
    ,   m_peakLevel(0.0)
    ,   m_spectrumBufferLength(0)
    ,   m_spectrumAnalyser()
    ,   m_spectrumPosition(0)
    ,   m_count(0)
{
    qRegisterMetaType<FrequencySpectrum>("FrequencySpectrum");
    qRegisterMetaType<WindowFunction>("WindowFunction");
    CHECKED_CONNECT(&m_spectrumAnalyser,
                    SIGNAL(spectrumChanged(FrequencySpectrum)),
                    this,
                    SLOT(spectrumChanged(FrequencySpectrum)));

    initialize();

#ifdef DUMP_DATA
    createOutputDir();
#endif

#ifdef DUMP_SPECTRUM
    m_spectrumAnalyser.setOutputPath(outputPath());
#endif
}

Engine::~Engine()
{

}

//-----------------------------------------------------------------------------
// Public functions
//-----------------------------------------------------------------------------

bool Engine::loadFile(const QString &fileName)
{
    reset();
    bool result = false;
    Q_ASSERT(!m_generateTone);
    Q_ASSERT(!m_file);
    Q_ASSERT(!fileName.isEmpty());
    m_file = new WavFile(this);
    if (m_file->open(fileName)) {
        if (isPCMS16LE(m_file->fileFormat())) {
            result = initialize();
        } else {
            emit errorMessage(tr("Audio format not supported"),
                              formatToString(m_file->fileFormat()));
        }
    } else {
        emit errorMessage(tr("Could not open file"), fileName);
    }
    if (result) {
        m_analysisFile = new WavFile(this);
        m_analysisFile->open(fileName);
    }
    return result;
}

bool Engine::generateTone(const Tone &tone)
{
    reset();
    Q_ASSERT(!m_generateTone);
    Q_ASSERT(!m_file);
    m_generateTone = true;
    m_tone = tone;
    ENGINE_DEBUG << "Engine::generateTone"
                 << "startFreq" << m_tone.startFreq
                 << "endFreq" << m_tone.endFreq
                 << "amp" << m_tone.amplitude;
    return initialize();
}

bool Engine::generateSweptTone(qreal amplitude)
{
    Q_ASSERT(!m_generateTone);
    Q_ASSERT(!m_file);
    m_generateTone = true;
    m_tone.startFreq = 1;
    m_tone.endFreq = 0;
    m_tone.amplitude = amplitude;
    ENGINE_DEBUG << "Engine::generateSweptTone"
                 << "startFreq" << m_tone.startFreq
                 << "amp" << m_tone.amplitude;
    return initialize();
}

bool Engine::initializeRecord()
{
    reset();
    ENGINE_DEBUG << "Engine::initializeRecord";
    Q_ASSERT(!m_generateTone);
    Q_ASSERT(!m_file);
    m_generateTone = false;
    m_tone = SweptTone();
    return initialize();
}

qint64 Engine::bufferLength() const
{
    return m_file ? m_file->size() : m_bufferLength;
}

void Engine::setWindowFunction(WindowFunction type)
{
    m_spectrumAnalyser.setWindowFunction(type);
}

//-----------------------------------------------------------------------------
// Public slots
//-----------------------------------------------------------------------------

void Engine::startRecording()
{
    if (m_audioInput) {
        if (QAudio::AudioInput == m_mode &&
            QAudio::SuspendedState == m_state) {
            m_audioInput->resume();
        } else {
            m_spectrumAnalyser.cancelCalculation();
            spectrumChanged(0, 0, FrequencySpectrum());

            m_buffer.fill(0);
            setRecordPosition(0, true);
            stopPlayback();
            m_mode = QAudio::AudioInput;
            CHECKED_CONNECT(m_audioInput, SIGNAL(stateChanged(QAudio::State)),
                            this, SLOT(audioStateChanged(QAudio::State)));
            CHECKED_CONNECT(m_audioInput, SIGNAL(notify()),
                            this, SLOT(audioNotify()));
            m_count = 0;
            m_dataLength = 0;
            emit dataLengthChanged(0);
            m_audioInputIODevice = m_audioInput->start();
            CHECKED_CONNECT(m_audioInputIODevice, SIGNAL(readyRead()),
                            this, SLOT(audioDataReady()));
        }
    }
}

void Engine::startPlayback()
{
    if (m_audioOutput) {
        if (QAudio::AudioOutput == m_mode &&
            QAudio::SuspendedState == m_state) {
#ifdef Q_OS_WIN
            // The Windows backend seems to internally go back into ActiveState
            // while still returning SuspendedState, so to ensure that it doesn't
            // ignore the resume() call, we first re-suspend
            m_audioOutput->suspend();
#endif
            m_audioOutput->resume();
        } else {
            m_spectrumAnalyser.cancelCalculation();
            spectrumChanged(0, 0, FrequencySpectrum());
            setPlayPosition(0, true);
            stopRecording();
            m_mode = QAudio::AudioOutput;
            CHECKED_CONNECT(m_audioOutput, SIGNAL(stateChanged(QAudio::State)),
                            this, SLOT(audioStateChanged(QAudio::State)));
            CHECKED_CONNECT(m_audioOutput, SIGNAL(notify()),
                            this, SLOT(audioNotify()));
            m_count = 0;
            if (m_file) {
                m_file->seek(0);
                m_bufferPosition = 0;
                m_dataLength = 0;
                m_audioOutput->start(m_file);
            } else {
                m_audioOutputIODevice.close();
                m_audioOutputIODevice.setBuffer(&m_buffer);
                m_audioOutputIODevice.open(QIODevice::ReadOnly);
                m_audioOutput->start(&m_audioOutputIODevice);
            }
        }
    }
}

void Engine::suspend()
{
    if (QAudio::ActiveState == m_state ||
        QAudio::IdleState == m_state) {
        switch (m_mode) {
        case QAudio::AudioInput:
            m_audioInput->suspend();
            break;
        case QAudio::AudioOutput:
            m_audioOutput->suspend();
            break;
        }
    }
}

void Engine::setAudioInputDevice(const QAudioDeviceInfo &device)
{
    if (device.deviceName() != m_audioInputDevice.deviceName()) {
        m_audioInputDevice = device;
        initialize();
    }
}

void Engine::setAudioOutputDevice(const QAudioDeviceInfo &device)
{
    if (device.deviceName() != m_audioOutputDevice.deviceName()) {
        m_audioOutputDevice = device;
        initialize();
    }
}

//-----------------------------------------------------------------------------
// Private slots
//-----------------------------------------------------------------------------

void Engine::audioNotify()
{
    switch (m_mode) {
    case QAudio::AudioInput: {
            const qint64 recordPosition = qMin(m_bufferLength, audioLength(m_format, m_audioInput->processedUSecs()));
            setRecordPosition(recordPosition);
            const qint64 levelPosition = m_dataLength - m_levelBufferLength;
            if (levelPosition >= 0)
                calculateLevel(levelPosition, m_levelBufferLength);
            if (m_dataLength >= m_spectrumBufferLength) {
                const qint64 spectrumPosition = m_dataLength - m_spectrumBufferLength;
                calculateSpectrum(spectrumPosition);
            }
            emit bufferChanged(0, m_dataLength, m_buffer);
        }
        break;
    case QAudio::AudioOutput: {
            const qint64 playPosition = audioLength(m_format, m_audioOutput->processedUSecs());
            setPlayPosition(qMin(bufferLength(), playPosition));
            const qint64 levelPosition = playPosition - m_levelBufferLength;
            const qint64 spectrumPosition = playPosition - m_spectrumBufferLength;
            if (m_file) {
                if (levelPosition > m_bufferPosition ||
                    spectrumPosition > m_bufferPosition ||
                    qMax(m_levelBufferLength, m_spectrumBufferLength) > m_dataLength) {
                    m_bufferPosition = 0;
                    m_dataLength = 0;
                    // Data needs to be read into m_buffer in order to be analysed
                    const qint64 readPos = qMax(qint64(0), qMin(levelPosition, spectrumPosition));
                    const qint64 readEnd = qMin(m_analysisFile->size(), qMax(levelPosition + m_levelBufferLength, spectrumPosition + m_spectrumBufferLength));
                    const qint64 readLen = readEnd - readPos + audioLength(m_format, WaveformWindowDuration);
                    qDebug() << "Engine::audioNotify [1]"
                             << "analysisFileSize" << m_analysisFile->size()
                             << "readPos" << readPos
                             << "readLen" << readLen;
                    if (m_analysisFile->seek(readPos + m_analysisFile->headerLength())) {
                        m_buffer.resize(readLen);
                        m_bufferPosition = readPos;
                        m_dataLength = m_analysisFile->read(m_buffer.data(), readLen);
                        qDebug() << "Engine::audioNotify [2]" << "bufferPosition" << m_bufferPosition << "dataLength" << m_dataLength;
                    } else {
                        qDebug() << "Engine::audioNotify [2]" << "file seek error";
                    }
                    emit bufferChanged(m_bufferPosition, m_dataLength, m_buffer);
                }
            } else {
                if (playPosition >= m_dataLength)
                    stopPlayback();
            }
            if (levelPosition >= 0 && levelPosition + m_levelBufferLength < m_bufferPosition + m_dataLength)
                calculateLevel(levelPosition, m_levelBufferLength);
            if (spectrumPosition >= 0 && spectrumPosition + m_spectrumBufferLength < m_bufferPosition + m_dataLength)
                calculateSpectrum(spectrumPosition);
        }
        break;
    }
}

void Engine::audioStateChanged(QAudio::State state)
{
    ENGINE_DEBUG << "Engine::audioStateChanged from" << m_state
                 << "to" << state;

    if (QAudio::IdleState == state && m_file && m_file->pos() == m_file->size()) {
        stopPlayback();
    } else {
        if (QAudio::StoppedState == state) {
            // Check error
            QAudio::Error error = QAudio::NoError;
            switch (m_mode) {
            case QAudio::AudioInput:
                error = m_audioInput->error();
                break;
            case QAudio::AudioOutput:
                error = m_audioOutput->error();
                break;
            }
            if (QAudio::NoError != error) {
                reset();
                return;
            }
        }
        setState(state);
    }
}

void Engine::audioDataReady()
{
    Q_ASSERT(0 == m_bufferPosition);
    const qint64 bytesReady = m_audioInput->bytesReady();
    const qint64 bytesSpace = m_buffer.size() - m_dataLength;
    const qint64 bytesToRead = qMin(bytesReady, bytesSpace);

    const qint64 bytesRead = m_audioInputIODevice->read(
                                       m_buffer.data() + m_dataLength,
                                       bytesToRead);

    if (bytesRead) {
        m_dataLength += bytesRead;
        emit dataLengthChanged(dataLength());
    }

    if (m_buffer.size() == m_dataLength)
        stopRecording();
}

void Engine::spectrumChanged(const FrequencySpectrum &spectrum)
{
    ENGINE_DEBUG << "Engine::spectrumChanged" << "pos" << m_spectrumPosition;
    emit spectrumChanged(m_spectrumPosition, m_spectrumBufferLength, spectrum);
}

//-----------------------------------------------------------------------------
// Private functions
//-----------------------------------------------------------------------------

void Engine::resetAudioDevices()
{
    delete m_audioInput;
    m_audioInput = 0;
    m_audioInputIODevice = 0;
    setRecordPosition(0);
    delete m_audioOutput;
    m_audioOutput = 0;
    setPlayPosition(0);
    m_spectrumPosition = 0;
    setLevel(0.0, 0.0, 0);
}

void Engine::reset()
{
    stopRecording();
    stopPlayback();
    setState(QAudio::AudioInput, QAudio::StoppedState);
    setFormat(QAudioFormat());
    m_generateTone = false;
    delete m_file;
    m_file = 0;
    delete m_analysisFile;
    m_analysisFile = 0;
    m_buffer.clear();
    m_bufferPosition = 0;
    m_bufferLength = 0;
    m_dataLength = 0;
    emit dataLengthChanged(0);
    resetAudioDevices();
}

bool Engine::initialize()
{
    bool result = false;

    QAudioFormat format = m_format;

    if (selectFormat()) {
        if (m_format != format) {
            resetAudioDevices();
            if (m_file) {
                emit bufferLengthChanged(bufferLength());
                emit dataLengthChanged(dataLength());
                emit bufferChanged(0, 0, m_buffer);
                setRecordPosition(bufferLength());
                result = true;
            } else {
                m_bufferLength = audioLength(m_format, BufferDurationUs);
                m_buffer.resize(m_bufferLength);
                m_buffer.fill(0);
                emit bufferLengthChanged(bufferLength());
                if (m_generateTone) {
                    if (0 == m_tone.endFreq) {
                        const qreal nyquist = nyquistFrequency(m_format);
                        m_tone.endFreq = qMin(qreal(SpectrumHighFreq), nyquist);
                    }
                    // Call function defined in utils.h, at global scope
                    ::generateTone(m_tone, m_format, m_buffer);
                    m_dataLength = m_bufferLength;
                    emit dataLengthChanged(dataLength());
                    emit bufferChanged(0, m_dataLength, m_buffer);
                    setRecordPosition(m_bufferLength);
                    result = true;
                } else {
                    emit bufferChanged(0, 0, m_buffer);
                    m_audioInput = new QAudioInput(m_audioInputDevice, m_format, this);
                    m_audioInput->setNotifyInterval(NotifyIntervalMs);
                    result = true;
                }
            }
            m_audioOutput = new QAudioOutput(m_audioOutputDevice, m_format, this);
            m_audioOutput->setNotifyInterval(NotifyIntervalMs);
        }
    } else {
        if (m_file)
            emit errorMessage(tr("Audio format not supported"),
                              formatToString(m_format));
        else if (m_generateTone)
            emit errorMessage(tr("No suitable format found"), "");
        else
            emit errorMessage(tr("No common input / output format found"), "");
    }

    ENGINE_DEBUG << "Engine::initialize" << "m_bufferLength" << m_bufferLength;
    ENGINE_DEBUG << "Engine::initialize" << "m_dataLength" << m_dataLength;
    ENGINE_DEBUG << "Engine::initialize" << "format" << m_format;

    return result;
}

bool Engine::selectFormat()
{
    bool foundSupportedFormat = false;

    if (m_file || QAudioFormat() != m_format) {
        QAudioFormat format = m_format;
        if (m_file)
            // Header is read from the WAV file; just need to check whether
            // it is supported by the audio output device
            format = m_file->fileFormat();
        if (m_audioOutputDevice.isFormatSupported(format)) {
            setFormat(format);
            foundSupportedFormat = true;
        }
    } else {

        QList<int> sampleRatesList;
    #ifdef Q_OS_WIN
        // The Windows audio backend does not correctly report format support
        // (see QTBUG-9100).  Furthermore, although the audio subsystem captures
        // at 11025Hz, the resulting audio is corrupted.
        sampleRatesList += 8000;
    #endif

        if (!m_generateTone)
            sampleRatesList += m_audioInputDevice.supportedSampleRates();

        sampleRatesList += m_audioOutputDevice.supportedSampleRates();
        sampleRatesList = sampleRatesList.toSet().toList(); // remove duplicates
        qSort(sampleRatesList);
        ENGINE_DEBUG << "Engine::initialize frequenciesList" << sampleRatesList;

        QList<int> channelsList;
        channelsList += m_audioInputDevice.supportedChannelCounts();
        channelsList += m_audioOutputDevice.supportedChannelCounts();
        channelsList = channelsList.toSet().toList();
        qSort(channelsList);
        ENGINE_DEBUG << "Engine::initialize channelsList" << channelsList;

        QAudioFormat format;
        format.setByteOrder(QAudioFormat::LittleEndian);
        format.setCodec("audio/pcm");
        format.setSampleSize(16);
        format.setSampleType(QAudioFormat::SignedInt);
        int sampleRate, channels;
        foreach (sampleRate, sampleRatesList) {
            if (foundSupportedFormat)
                break;
            format.setSampleRate(sampleRate);
            foreach (channels, channelsList) {
                format.setChannelCount(channels);
                const bool inputSupport = m_generateTone ||
                                          m_audioInputDevice.isFormatSupported(format);
                const bool outputSupport = m_audioOutputDevice.isFormatSupported(format);
                ENGINE_DEBUG << "Engine::initialize checking " << format
                             << "input" << inputSupport
                             << "output" << outputSupport;
                if (inputSupport && outputSupport) {
                    foundSupportedFormat = true;
                    break;
                }
            }
        }

        if (!foundSupportedFormat)
            format = QAudioFormat();

        setFormat(format);
    }

    return foundSupportedFormat;
}

void Engine::stopRecording()
{
    if (m_audioInput) {
        m_audioInput->stop();
        QCoreApplication::instance()->processEvents();
        m_audioInput->disconnect();
    }
    m_audioInputIODevice = 0;

#ifdef DUMP_AUDIO
    dumpData();
#endif
}

void Engine::stopPlayback()
{
    if (m_audioOutput) {
        m_audioOutput->stop();
        QCoreApplication::instance()->processEvents();
        m_audioOutput->disconnect();
        setPlayPosition(0);
    }
}

void Engine::setState(QAudio::State state)
{
    const bool changed = (m_state != state);
    m_state = state;
    if (changed)
        emit stateChanged(m_mode, m_state);
}

void Engine::setState(QAudio::Mode mode, QAudio::State state)
{
    const bool changed = (m_mode != mode || m_state != state);
    m_mode = mode;
    m_state = state;
    if (changed)
        emit stateChanged(m_mode, m_state);
}

void Engine::setRecordPosition(qint64 position, bool forceEmit)
{
    const bool changed = (m_recordPosition != position);
    m_recordPosition = position;
    if (changed || forceEmit)
        emit recordPositionChanged(m_recordPosition);
}

void Engine::setPlayPosition(qint64 position, bool forceEmit)
{
    const bool changed = (m_playPosition != position);
    m_playPosition = position;
    if (changed || forceEmit)
        emit playPositionChanged(m_playPosition);
}

void Engine::calculateLevel(qint64 position, qint64 length)
{
#ifdef DISABLE_LEVEL
    Q_UNUSED(position)
    Q_UNUSED(length)
#else
    Q_ASSERT(position + length <= m_bufferPosition + m_dataLength);

    qreal peakLevel = 0.0;

    qreal sum = 0.0;
    const char *ptr = m_buffer.constData() + position - m_bufferPosition;
    const char *const end = ptr + length;
    while (ptr < end) {
        const qint16 value = *reinterpret_cast<const qint16*>(ptr);
        const qreal fracValue = pcmToReal(value);
        peakLevel = qMax(peakLevel, fracValue);
        sum += fracValue * fracValue;
        ptr += 2;
    }
    const int numSamples = length / 2;
    qreal rmsLevel = sqrt(sum / numSamples);

    rmsLevel = qMax(qreal(0.0), rmsLevel);
    rmsLevel = qMin(qreal(1.0), rmsLevel);
    setLevel(rmsLevel, peakLevel, numSamples);

    ENGINE_DEBUG << "Engine::calculateLevel" << "pos" << position << "len" << length
                 << "rms" << rmsLevel << "peak" << peakLevel;
#endif
}

void Engine::calculateSpectrum(qint64 position)
{
#ifdef DISABLE_SPECTRUM
    Q_UNUSED(position)
#else
    Q_ASSERT(position + m_spectrumBufferLength <= m_bufferPosition + m_dataLength);
    Q_ASSERT(0 == m_spectrumBufferLength % 2); // constraint of FFT algorithm

    // QThread::currentThread is marked 'for internal use only', but
    // we're only using it for debug output here, so it's probably OK :)
    ENGINE_DEBUG << "Engine::calculateSpectrum" << QThread::currentThread()
                 << "count" << m_count << "pos" << position << "len" << m_spectrumBufferLength
                 << "spectrumAnalyser.isReady" << m_spectrumAnalyser.isReady();

    if (m_spectrumAnalyser.isReady()) {
        m_spectrumBuffer = QByteArray::fromRawData(m_buffer.constData() + position - m_bufferPosition,
                                                   m_spectrumBufferLength);
        m_spectrumPosition = position;
        m_spectrumAnalyser.calculate(m_spectrumBuffer, m_format);
    }
#endif
}

void Engine::setFormat(const QAudioFormat &format)
{
    const bool changed = (format != m_format);
    m_format = format;
    m_levelBufferLength = audioLength(m_format, LevelWindowUs);
    m_spectrumBufferLength = SpectrumLengthSamples *
                            (m_format.sampleSize() / 8) * m_format.channelCount();
    if (changed)
        emit formatChanged(m_format);
}

void Engine::setLevel(qreal rmsLevel, qreal peakLevel, int numSamples)
{
    m_rmsLevel = rmsLevel;
    m_peakLevel = peakLevel;
    emit levelChanged(m_rmsLevel, m_peakLevel, numSamples);
}

#ifdef DUMP_DATA
void Engine::createOutputDir()
{
    m_outputDir.setPath("output");

    // Ensure output directory exists and is empty
    if (m_outputDir.exists()) {
        const QStringList files = m_outputDir.entryList(QDir::Files);
        QString file;
        foreach (file, files)
            m_outputDir.remove(file);
    } else {
        QDir::current().mkdir("output");
    }
}
#endif // DUMP_DATA

#ifdef DUMP_AUDIO
void Engine::dumpData()
{
    const QString txtFileName = m_outputDir.filePath("data.txt");
    QFile txtFile(txtFileName);
    txtFile.open(QFile::WriteOnly | QFile::Text);
    QTextStream stream(&txtFile);
    const qint16 *ptr = reinterpret_cast<const qint16*>(m_buffer.constData());
    const int numSamples = m_dataLength / (2 * m_format.channels());
    for (int i=0; i<numSamples; ++i) {
        stream << i << "\t" << *ptr << "\n";
        ptr += m_format.channels();
    }

    const QString pcmFileName = m_outputDir.filePath("data.pcm");
    QFile pcmFile(pcmFileName);
    pcmFile.open(QFile::WriteOnly);
    pcmFile.write(m_buffer.constData(), m_dataLength);
}
#endif // DUMP_AUDIO

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.