Cleanup the audio decoder architecture

QPlatformAudioDecoder should not be a QObject, instead just
have a pointer back to the front-end class. The backend is
now also properly owned by the frontend.

Get rid of QAudioDecoderPrivate, we don't need it anymore.

Fix the audiodecoderbackend autotest and the audiodecoder
example.

Change-Id: Id9a3368788b5398f37b77be819e8f12947ba045f
Reviewed-by: André de la Rocha <andre.rocha@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

19 files changed, 157 insertions, 175 deletions

diff --git a/examples/multimedia/audiodecoder/audiodecoder.cpp b/examples/multimedia/audiodecoder/audiodecoder.cpp
index 7c46be800..401b41bfd 100644
--- a/examples/multimedia/audiodecoder/audiodecoder.cpp
+++ b/examples/multimedia/audiodecoder/audiodecoder.cpp
@@ -99,7 +99,7 @@ AudioDecoder::~AudioDecoder()
 
 void AudioDecoder::setSource(const QString &fileName)
 {
-    m_decoder.setSource(fileName);
+    m_decoder.setSource(QUrl::fromLocalFile(fileName));
 }
 
 void AudioDecoder::start()
diff --git a/src/multimedia/audio/qaudiodecoder.cpp b/src/multimedia/audio/qaudiodecoder.cpp
index 6de7ab285..9c2c3bc36 100644
--- a/src/multimedia/audio/qaudiodecoder.cpp
+++ b/src/multimedia/audio/qaudiodecoder.cpp
@@ -71,91 +71,27 @@ QT_BEGIN_NAMESPACE
     \sa QAudioBuffer
 */
 
-#define Q_DECLARE_NON_CONST_PUBLIC(Class) \
-    inline Class* q_func() { return static_cast<Class *>(q_ptr); } \
-    friend class Class;
-
-class QAudioDecoderPrivate : public QObjectPrivate
-{
-    Q_DECLARE_NON_CONST_PUBLIC(QAudioDecoder)
-
-public:
-    QPlatformAudioDecoder *control = nullptr;
-    QAudioDecoder::State state = QAudioDecoder::StoppedState;
-    QAudioDecoder::Error error = QAudioDecoder::NoError;
-    QString errorString;
-
-    void _q_stateChanged(QAudioDecoder::State state);
-    void _q_error(int error, const QString &errorString);
-};
-
-#undef Q_DECLARE_NON_CONST_PUBLIC
-
-void QAudioDecoderPrivate::_q_stateChanged(QAudioDecoder::State ps)
-{
-    Q_Q(QAudioDecoder);
-
-    if (ps != state) {
-        state = ps;
-
-        emit q->stateChanged(ps);
-    }
-}
-
-void QAudioDecoderPrivate::_q_error(int error, const QString &errorString)
-{
-    Q_Q(QAudioDecoder);
-
-    this->error = QAudioDecoder::Error(error);
-    this->errorString = errorString;
-
-    emit q->error(this->error);
-}
-
 /*!
     Construct an QAudioDecoder instance with \a parent.
 */
 QAudioDecoder::QAudioDecoder(QObject *parent)
-    : QObject(*new QAudioDecoderPrivate, parent)
+    : QObject(parent)
 {
-    Q_D(QAudioDecoder);
-
-    d->control = QPlatformMediaIntegration::instance()->createAudioDecoder();
-    if (d->control != nullptr) {
-        connect(d->control, SIGNAL(stateChanged(QAudioDecoder::State)), SLOT(_q_stateChanged(QAudioDecoder::State)));
-        connect(d->control, SIGNAL(error(int,QString)), SLOT(_q_error(int,QString)));
-
-        connect(d->control, SIGNAL(formatChanged(QAudioFormat)), SIGNAL(formatChanged(QAudioFormat)));
-        connect(d->control, SIGNAL(sourceChanged()), SIGNAL(sourceChanged()));
-        connect(d->control, SIGNAL(bufferReady()), this, SIGNAL(bufferReady()));
-        connect(d->control ,SIGNAL(bufferAvailableChanged(bool)), this, SIGNAL(bufferAvailableChanged(bool)));
-        connect(d->control ,SIGNAL(finished()), this, SIGNAL(finished()));
-        connect(d->control ,SIGNAL(positionChanged(qint64)), this, SIGNAL(positionChanged(qint64)));
-        connect(d->control ,SIGNAL(durationChanged(qint64)), this, SIGNAL(durationChanged(qint64)));
-    } else {
-       d->error = NotSupportedError;
-       d->errorString = tr("The QAudioDecoder object does not have a valid service");
-    }
+    decoder = QPlatformMediaIntegration::instance()->createAudioDecoder(this);
 }
 
 
 /*!
     Destroys the audio decoder object.
 */
-QAudioDecoder::~QAudioDecoder()
-{
-    Q_D(QAudioDecoder);
-
-    if (d->control)
-        delete d->control;
-}
+QAudioDecoder::~QAudioDecoder() = default;
 
 /*!
     Returns true is audio decoding is supported on this platform.
 */
 bool QAudioDecoder::isAvailable() const
 {
-    return d_func()->control != nullptr;
+    return decoder != nullptr;
 }
 
 /*!
@@ -163,7 +99,7 @@ bool QAudioDecoder::isAvailable() const
 */
 QAudioDecoder::State QAudioDecoder::state() const
 {
-    return d_func()->state;
+    return decoder ? decoder->state() : QAudioDecoder::StoppedState;
 }
 
 /*!
@@ -171,7 +107,9 @@ QAudioDecoder::State QAudioDecoder::state() const
 */
 QAudioDecoder::Error QAudioDecoder::error() const
 {
-    return d_func()->error;
+    if (!decoder)
+        return NotSupportedError;
+    return decoder->error();
 }
 
 /*!
@@ -180,7 +118,9 @@ QAudioDecoder::Error QAudioDecoder::error() const
 */
 QString QAudioDecoder::errorString() const
 {
-    return d_func()->errorString;
+    if (!decoder)
+        return tr("QAudioDecoder not supported.");
+    return decoder->errorString();
 }
 
 /*!
@@ -197,20 +137,13 @@ QString QAudioDecoder::errorString() const
 */
 void QAudioDecoder::start()
 {
-    Q_D(QAudioDecoder);
-
-    if (d->control == nullptr) {
-        QMetaObject::invokeMethod(this, "_q_error", Qt::QueuedConnection,
-                                    Q_ARG(int, QAudioDecoder::NotSupportedError),
-                                    Q_ARG(QString, tr("The QAudioDecoder object does not have a valid service")));
+    if (decoder == nullptr)
         return;
-    }
 
     // Reset error conditions
-    d->error = NoError;
-    d->errorString.clear();
+    decoder->clearError();
 
-    d->control->start();
+    decoder->start();
 }
 
 /*!
@@ -218,10 +151,8 @@ void QAudioDecoder::start()
 */
 void QAudioDecoder::stop()
 {
-    Q_D(QAudioDecoder);
-
-    if (d->control != nullptr)
-        d->control->stop();
+    if (decoder != nullptr)
+        decoder->stop();
 }
 
 /*!
@@ -231,9 +162,8 @@ void QAudioDecoder::stop()
 */
 QUrl QAudioDecoder::source() const
 {
-    Q_D(const QAudioDecoder);
-    if (d->control)
-        return d->control->source();
+    if (decoder)
+        return decoder->source();
     return QString();
 }
 
@@ -248,10 +178,11 @@ QUrl QAudioDecoder::source() const
 */
 void QAudioDecoder::setSource(const QUrl &fileName)
 {
-    Q_D(QAudioDecoder);
+    if (!decoder)
+        return;
 
-    if (d->control != nullptr)
-        d_func()->control->setSource(fileName);
+    decoder->clearError();
+    decoder->setSource(fileName);
 }
 
 /*!
@@ -260,9 +191,8 @@ void QAudioDecoder::setSource(const QUrl &fileName)
 */
 QIODevice *QAudioDecoder::sourceDevice() const
 {
-    Q_D(const QAudioDecoder);
-    if (d->control)
-        return d->control->sourceDevice();
+    if (decoder)
+        return decoder->sourceDevice();
     return nullptr;
 }
 
@@ -277,10 +207,8 @@ QIODevice *QAudioDecoder::sourceDevice() const
 */
 void QAudioDecoder::setSourceDevice(QIODevice *device)
 {
-    Q_D(QAudioDecoder);
-
-    if (d->control != nullptr)
-        d_func()->control->setSourceDevice(device);
+    if (decoder != nullptr)
+        decoder->setSourceDevice(device);
 }
 
 /*!
@@ -292,9 +220,8 @@ void QAudioDecoder::setSourceDevice(QIODevice *device)
 */
 QAudioFormat QAudioDecoder::audioFormat() const
 {
-    Q_D(const QAudioDecoder);
-    if (d->control)
-        return d->control->audioFormat();
+    if (decoder)
+        return decoder->audioFormat();
     return QAudioFormat();
 }
 
@@ -316,13 +243,11 @@ QAudioFormat QAudioDecoder::audioFormat() const
 */
 void QAudioDecoder::setAudioFormat(const QAudioFormat &format)
 {
-    Q_D(QAudioDecoder);
-
     if (state() != QAudioDecoder::StoppedState)
         return;
 
-    if (d->control != nullptr)
-        d_func()->control->setAudioFormat(format);
+    if (decoder != nullptr)
+        decoder->setAudioFormat(format);
 }
 
 /*!
@@ -332,9 +257,8 @@ void QAudioDecoder::setAudioFormat(const QAudioFormat &format)
 */
 bool QAudioDecoder::bufferAvailable() const
 {
-    Q_D(const QAudioDecoder);
-    if (d->control)
-        return d->control->bufferAvailable();
+    if (decoder)
+        return decoder->bufferAvailable();
     return false;
 }
 
@@ -345,9 +269,8 @@ bool QAudioDecoder::bufferAvailable() const
 
 qint64 QAudioDecoder::position() const
 {
-    Q_D(const QAudioDecoder);
-    if (d->control)
-        return d->control->position();
+    if (decoder)
+        return decoder->position();
     return -1;
 }
 
@@ -358,9 +281,8 @@ qint64 QAudioDecoder::position() const
 
 qint64 QAudioDecoder::duration() const
 {
-    Q_D(const QAudioDecoder);
-    if (d->control)
-        return d->control->duration();
+    if (decoder)
+        return decoder->duration();
     return -1;
 }
 
@@ -376,11 +298,8 @@ qint64 QAudioDecoder::duration() const
 
 QAudioBuffer QAudioDecoder::read() const
 {
-    Q_D(const QAudioDecoder);
-
-    if (d->control) {
-        return d->control->read();
-    }
+    if (decoder)
+        return decoder->read();
 
     return QAudioBuffer();
 }
diff --git a/src/multimedia/audio/qaudiodecoder.h b/src/multimedia/audio/qaudiodecoder.h
index b3f7c6bdc..9b7c360d5 100644
--- a/src/multimedia/audio/qaudiodecoder.h
+++ b/src/multimedia/audio/qaudiodecoder.h
@@ -47,7 +47,7 @@
 
 QT_BEGIN_NAMESPACE
 
-class QAudioDecoderPrivate;
+class QPlatformAudioDecoder;
 class Q_MULTIMEDIA_EXPORT QAudioDecoder : public QObject
 {
     Q_OBJECT
@@ -120,9 +120,7 @@ Q_SIGNALS:
 
 private:
     Q_DISABLE_COPY(QAudioDecoder)
-    Q_DECLARE_PRIVATE(QAudioDecoder)
-    Q_PRIVATE_SLOT(d_func(), void _q_stateChanged(QAudioDecoder::State))
-    Q_PRIVATE_SLOT(d_func(), void _q_error(int, const QString &))
+    QPlatformAudioDecoder *decoder;
 };
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder.cpp b/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder.cpp
index 0f5a0ee0a..817e168bf 100644
--- a/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder.cpp
+++ b/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder.cpp
@@ -73,7 +73,7 @@ typedef enum {
 
 
 
-QGstreamerAudioDecoder::QGstreamerAudioDecoder(QObject *parent)
+QGstreamerAudioDecoder::QGstreamerAudioDecoder(QAudioDecoder *parent)
     : QPlatformAudioDecoder(parent),
     m_playbin(GST_PIPELINE_CAST(QGstElement("playbin", "playbin").element()))
 {
@@ -352,6 +352,7 @@ void QGstreamerAudioDecoder::start()
     m_pendingState = QAudioDecoder::DecodingState;
     if (m_playbin.setState(GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE) {
         qWarning() << "GStreamer; Unable to start decoding process";
+        m_playbin.dumpGraph("failed");
         m_pendingState = m_state = QAudioDecoder::StoppedState;
 
         emit stateChanged(m_state);
@@ -475,19 +476,19 @@ void QGstreamerAudioDecoder::processInvalidMedia(QAudioDecoder::Error errorCode,
 GstFlowReturn QGstreamerAudioDecoder::new_sample(GstAppSink *, gpointer user_data)
 {
     // "Note that the preroll buffer will also be returned as the first buffer when calling gst_app_sink_pull_buffer()."
-    QGstreamerAudioDecoder *control = reinterpret_cast<QGstreamerAudioDecoder*>(user_data);
+    QGstreamerAudioDecoder *decoder = reinterpret_cast<QGstreamerAudioDecoder*>(user_data);
 
     int buffersAvailable;
     {
-        QMutexLocker locker(&control->m_buffersMutex);
-        buffersAvailable = control->m_buffersAvailable;
-        control->m_buffersAvailable++;
-        Q_ASSERT(control->m_buffersAvailable <= MAX_BUFFERS_IN_QUEUE);
+        QMutexLocker locker(&decoder->m_buffersMutex);
+        buffersAvailable = decoder->m_buffersAvailable;
+        decoder->m_buffersAvailable++;
+        Q_ASSERT(decoder->m_buffersAvailable <= MAX_BUFFERS_IN_QUEUE);
     }
 
     if (!buffersAvailable)
-        QMetaObject::invokeMethod(control, "bufferAvailableChanged", Qt::QueuedConnection, Q_ARG(bool, true));
-    QMetaObject::invokeMethod(control, "bufferReady", Qt::QueuedConnection);
+        decoder->bufferAvailableChanged(true);
+    decoder->bufferReady();
     return GST_FLOW_OK;
 }
 
diff --git a/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder_p.h b/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder_p.h
index 22d024801..be2343916 100644
--- a/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder_p.h
+++ b/src/multimedia/platform/gstreamer/audio/qgstreameraudiodecoder_p.h
@@ -78,7 +78,7 @@ class QGstreamerAudioDecoder
     Q_OBJECT
 
 public:
-    QGstreamerAudioDecoder(QObject *parent);
+    QGstreamerAudioDecoder(QAudioDecoder *parent);
     virtual ~QGstreamerAudioDecoder();
 
     // QAudioDecoder interface
diff --git a/src/multimedia/platform/gstreamer/qgstreamerintegration.cpp b/src/multimedia/platform/gstreamer/qgstreamerintegration.cpp
index fec548162..ba1baa641 100644
--- a/src/multimedia/platform/gstreamer/qgstreamerintegration.cpp
+++ b/src/multimedia/platform/gstreamer/qgstreamerintegration.cpp
@@ -54,6 +54,8 @@ QT_BEGIN_NAMESPACE
 QGstreamerIntegration::QGstreamerIntegration()
 {
     gst_init(nullptr, nullptr);
+    m_devices = new QGstreamerMediaDevices();
+    m_formatsInfo = new QGstreamerFormatInfo();
 }
 
 QGstreamerIntegration::~QGstreamerIntegration()
@@ -64,21 +66,17 @@ QGstreamerIntegration::~QGstreamerIntegration()
 
 QPlatformMediaDevices *QGstreamerIntegration::devices()
 {
-    if (!m_devices)
-        m_devices = new QGstreamerMediaDevices();
     return m_devices;
 }
 
 QPlatformMediaFormatInfo *QGstreamerIntegration::formatInfo()
 {
-    if (!m_formatsInfo)
-        m_formatsInfo = new QGstreamerFormatInfo();
     return m_formatsInfo;
 }
 
-QPlatformAudioDecoder *QGstreamerIntegration::createAudioDecoder()
+QPlatformAudioDecoder *QGstreamerIntegration::createAudioDecoder(QAudioDecoder *decoder)
 {
-    return new QGstreamerAudioDecoder(nullptr);
+    return new QGstreamerAudioDecoder(decoder);
 }
 
 QPlatformMediaCaptureSession *QGstreamerIntegration::createCaptureSession(QMediaRecorder::CaptureMode mode)
diff --git a/src/multimedia/platform/gstreamer/qgstreamerintegration_p.h b/src/multimedia/platform/gstreamer/qgstreamerintegration_p.h
index 7781b538e..6606cc356 100644
--- a/src/multimedia/platform/gstreamer/qgstreamerintegration_p.h
+++ b/src/multimedia/platform/gstreamer/qgstreamerintegration_p.h
@@ -69,7 +69,7 @@ public:
     QPlatformMediaDevices *devices() override;
     QPlatformMediaFormatInfo *formatInfo() override;
 
-    QPlatformAudioDecoder *createAudioDecoder() override;
+    QPlatformAudioDecoder *createAudioDecoder(QAudioDecoder *decoder) override;
     QPlatformMediaCaptureSession *createCaptureSession(QMediaRecorder::CaptureMode mode) override;
     QPlatformMediaPlayer *createPlayer(QMediaPlayer *player) override;
     QPlatformCamera *createCamera(QCamera *) override;
diff --git a/src/multimedia/platform/qplatformaudiodecoder.cpp b/src/multimedia/platform/qplatformaudiodecoder.cpp
index 2b29fd1ac..b7da0a304 100644
--- a/src/multimedia/platform/qplatformaudiodecoder.cpp
+++ b/src/multimedia/platform/qplatformaudiodecoder.cpp
@@ -38,6 +38,7 @@
 ****************************************************************************/
 
 #include "qplatformaudiodecoder_p.h"
+#include "qthread.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -59,8 +60,9 @@ QT_BEGIN_NAMESPACE
 /*!
     Constructs a new audio decoder control with the given \a parent.
 */
-QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
-    : QObject(parent)
+QPlatformAudioDecoder::QPlatformAudioDecoder(QAudioDecoder *parent)
+    : QObject(parent),
+    q(parent)
 {
 }
 
@@ -70,6 +72,14 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
     Returns the state of a player control.
 */
 
+void QPlatformAudioDecoder::stateChanged(QAudioDecoder::State newState)
+{
+    if (m_state == newState)
+        return;
+    m_state = newState;
+    emit q->stateChanged(newState);
+}
+
 /*!
     \fn QPlatformAudioDecoder::stateChanged(QAudioDecoder::State newState)
 
@@ -134,24 +144,41 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
     Signals that an \a error has occurred.  The \a errorString provides a more detailed explanation.
 */
 
+void QPlatformAudioDecoder::error(int error, const QString &errorString)
+{
+    if (error == m_error && errorString == m_errorString)
+        return;
+    m_error = QAudioDecoder::Error(error);
+    m_errorString = errorString;
+
+    emit q->error(m_error);
+}
+
 /*!
     \fn QPlatformAudioDecoder::bufferAvailableChanged(bool available)
 
     Signals that the bufferAvailable property has changed to \a available.
 */
+void QPlatformAudioDecoder::bufferAvailableChanged(bool available)
+{
+    if (QThread::currentThread() != q->thread())
+        QMetaObject::invokeMethod(q, "bufferAvailableChanged", Qt::QueuedConnection, Q_ARG(bool, available));
+    else
+        emit q->bufferAvailableChanged(available);
+}
 
 /*!
     \fn QPlatformAudioDecoder::bufferReady()
 
     Signals that a new buffer is ready for reading.
 */
-
-/*!
-    \fn QPlatformAudioDecoder::bufferAvailable() const
-
-    Returns true if a buffer is available to be read,
-    and false otherwise.
-*/
+void QPlatformAudioDecoder::bufferReady()
+{
+    if (QThread::currentThread() != q->thread())
+        QMetaObject::invokeMethod(q, "bufferReady", Qt::QueuedConnection);
+    else
+        emit q->bufferReady();
+}
 
 /*!
     \fn QPlatformAudioDecoder::sourceChanged()
@@ -160,6 +187,10 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
 
     \sa source(), sourceDevice()
 */
+void QPlatformAudioDecoder::sourceChanged()
+{
+    emit q->sourceChanged();
+}
 
 /*!
     \fn QPlatformAudioDecoder::formatChanged(const QAudioFormat &format)
@@ -168,6 +199,10 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
 
     \sa audioFormat(), setAudioFormat()
 */
+void QPlatformAudioDecoder::formatChanged(const QAudioFormat &format)
+{
+    emit q->formatChanged(format);
+}
 
 /*!
     \fn void QPlatformAudioDecoder::finished()
@@ -177,6 +212,10 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
 
     \sa start(), stop(), error()
 */
+void QPlatformAudioDecoder::finished()
+{
+    emit q->finished();
+}
 
 /*!
     \fn void QPlatformAudioDecoder::positionChanged(qint64 position)
@@ -185,6 +224,10 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
 
     \sa durationChanged()
 */
+void QPlatformAudioDecoder::positionChanged(qint64 position)
+{
+    q->positionChanged(position);
+}
 
 /*!
     \fn void QPlatformAudioDecoder::durationChanged(qint64 duration)
@@ -193,6 +236,10 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
 
     \sa positionChanged()
 */
+void QPlatformAudioDecoder::durationChanged(qint64 duration)
+{
+    q->durationChanged(duration);
+}
 
 /*!
     \fn QPlatformAudioDecoder::audioFormat() const
@@ -237,5 +284,3 @@ QPlatformAudioDecoder::QPlatformAudioDecoder(QObject *parent)
 */
 
 QT_END_NAMESPACE
-
-#include "moc_qplatformaudiodecoder_p.cpp"
diff --git a/src/multimedia/platform/qplatformaudiodecoder_p.h b/src/multimedia/platform/qplatformaudiodecoder_p.h
index 09e3a02b4..91877e647 100644
--- a/src/multimedia/platform/qplatformaudiodecoder_p.h
+++ b/src/multimedia/platform/qplatformaudiodecoder_p.h
@@ -56,6 +56,7 @@
 #include <QtCore/qpair.h>
 
 #include <QtMultimedia/qaudiobuffer.h>
+#include <QtMultimedia/qaudiodecoder.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -65,7 +66,7 @@ class Q_MULTIMEDIA_EXPORT QPlatformAudioDecoder : public QObject
     Q_OBJECT
 
 public:
-    virtual QAudioDecoder::State state() const = 0;
+    virtual QAudioDecoder::State state() const { return m_state; }
 
     virtual QUrl source() const = 0;
     virtual void setSource(const QUrl &fileName) = 0;
@@ -85,12 +86,12 @@ public:
     virtual qint64 position() const = 0;
     virtual qint64 duration() const = 0;
 
-Q_SIGNALS:
     void stateChanged(QAudioDecoder::State newState);
     void formatChanged(const QAudioFormat &format);
     void sourceChanged();
 
     void error(int error, const QString &errorString);
+    void clearError() { error(QAudioDecoder::NoError, QString()); }
 
     void bufferReady();
     void bufferAvailableChanged(bool available);
@@ -99,8 +100,17 @@ Q_SIGNALS:
     void positionChanged(qint64 position);
     void durationChanged(qint64 duration);
 
+    QAudioDecoder::Error error() const { return m_error; }
+    QString errorString() const { return m_errorString; }
+
 protected:
-    explicit QPlatformAudioDecoder(QObject *parent = nullptr);
+    explicit QPlatformAudioDecoder(QAudioDecoder *parent);
+private:
+    QAudioDecoder *q = nullptr;
+
+    QAudioDecoder::State m_state = QAudioDecoder::StoppedState;
+    QAudioDecoder::Error m_error = QAudioDecoder::NoError;
+    QString m_errorString;
 };
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/qplatformmediaintegration.cpp b/src/multimedia/platform/qplatformmediaintegration.cpp
index dd9843f2d..dbfb5eca7 100644
--- a/src/multimedia/platform/qplatformmediaintegration.cpp
+++ b/src/multimedia/platform/qplatformmediaintegration.cpp
@@ -39,6 +39,8 @@
 
 #include <qtmultimediaglobal_p.h>
 #include "qplatformmediaintegration_p.h"
+#include <qatomic.h>
+#include <qmutex.h>
 
 #if QT_CONFIG(gstreamer)
 #include <private/qgstreamerintegration_p.h>
@@ -66,22 +68,27 @@ namespace {
 struct Holder {
     ~Holder()
     {
+        QMutexLocker locker(&mutex);
         delete nativeInstance;
         nativeInstance = nullptr;
         instance = nullptr;
     }
+    QBasicMutex mutex;
     QPlatformMediaIntegration *instance = nullptr;
-    QPlatformMediaIntegration *nativeInstance = nullptr;
+    QAtomicPointer<QPlatformMediaIntegration> nativeInstance = nullptr;
 } holder;
 
 }
 
 QPlatformMediaIntegration *QPlatformMediaIntegration::instance()
 {
-    if (!holder.nativeInstance)
-        holder.nativeInstance = new PlatformIntegration;
+    if (!holder.nativeInstance.loadRelaxed()) {
+        QMutexLocker locker(&holder.mutex);
+        if (!holder.nativeInstance.loadAcquire())
+            holder.nativeInstance.storeRelease(new PlatformIntegration);
+    }
     if (!holder.instance)
-        holder.instance = holder.nativeInstance;
+        holder.instance = holder.nativeInstance.loadRelaxed();
     return holder.instance;
 }
 
diff --git a/src/multimedia/platform/qplatformmediaintegration_p.h b/src/multimedia/platform/qplatformmediaintegration_p.h
index 0a089f9dc..1bd943b8d 100644
--- a/src/multimedia/platform/qplatformmediaintegration_p.h
+++ b/src/multimedia/platform/qplatformmediaintegration_p.h
@@ -56,6 +56,7 @@
 QT_BEGIN_NAMESPACE
 
 class QMediaPlayer;
+class QAudioDecoder;
 class QCamera;
 class QMediaEncoder;
 class QCameraImageCapture;
@@ -84,7 +85,7 @@ public:
     virtual QPlatformMediaDevices *devices() = 0;
     virtual QPlatformMediaFormatInfo *formatInfo() = 0;
 
-    virtual QPlatformAudioDecoder *createAudioDecoder() { return nullptr; }
+    virtual QPlatformAudioDecoder *createAudioDecoder(QAudioDecoder *) { return nullptr; }
     // ### get rid of the mode once refactoring is done
     virtual QPlatformMediaCaptureSession *createCaptureSession(QMediaRecorder::CaptureMode /*mode*/ = QMediaRecorder::AudioAndVideo) { return nullptr; }
     virtual QPlatformMediaPlayer *createPlayer(QMediaPlayer *) { return nullptr; }
diff --git a/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol.cpp b/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol.cpp
index 5a07d7e08..953281f31 100644
--- a/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol.cpp
+++ b/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol.cpp
@@ -40,7 +40,7 @@
 #include "Wmcodecdsp.h"
 #include "mfaudiodecodercontrol_p.h"
 
-MFAudioDecoderControl::MFAudioDecoderControl(QObject *parent)
+MFAudioDecoderControl::MFAudioDecoderControl(QAudioDecoder *parent)
     : QPlatformAudioDecoder(parent)
     , m_decoderSourceReader(new MFDecoderSourceReader)
     , m_sourceResolver(new SourceResolver)
diff --git a/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol_p.h b/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol_p.h
index 563b9efb6..56edb95c0 100644
--- a/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol_p.h
+++ b/src/multimedia/platform/windows/decoder/mfaudiodecodercontrol_p.h
@@ -61,7 +61,7 @@ class MFAudioDecoderControl : public QPlatformAudioDecoder
 {
     Q_OBJECT
 public:
-    MFAudioDecoderControl(QObject *parent = 0);
+    MFAudioDecoderControl(QAudioDecoder *parent);
     ~MFAudioDecoderControl();
 
     QAudioDecoder::State state() const;
diff --git a/src/multimedia/platform/windows/qwindowsintegration.cpp b/src/multimedia/platform/windows/qwindowsintegration.cpp
index a399d3be8..9180fa4d2 100644
--- a/src/multimedia/platform/windows/qwindowsintegration.cpp
+++ b/src/multimedia/platform/windows/qwindowsintegration.cpp
@@ -93,9 +93,9 @@ QPlatformMediaCaptureSession *QWindowsIntegration::createCaptureSession(QMediaRe
     return new QWindowsMediaCaptureService();
 }
 
-QPlatformAudioDecoder *QWindowsIntegration::createAudioDecoder()
+QPlatformAudioDecoder *QWindowsIntegration::createAudioDecoder(QAudioDecoder *decoder)
 {
-    return new MFAudioDecoderControl;
+    return new MFAudioDecoderControl(decoder);
 }
 
 QPlatformMediaPlayer *QWindowsIntegration::createPlayer(QMediaPlayer *parent)
diff --git a/src/multimedia/platform/windows/qwindowsintegration_p.h b/src/multimedia/platform/windows/qwindowsintegration_p.h
index 98b159206..c0fb6d4a6 100644
--- a/src/multimedia/platform/windows/qwindowsintegration_p.h
+++ b/src/multimedia/platform/windows/qwindowsintegration_p.h
@@ -72,7 +72,7 @@ public:
 
     QPlatformMediaCaptureSession *createCaptureSession(QMediaRecorder::CaptureMode) override;
 
-    QPlatformAudioDecoder *createAudioDecoder() override;
+    QPlatformAudioDecoder *createAudioDecoder(QAudioDecoder *decoder) override;
     QPlatformMediaPlayer *createPlayer(QMediaPlayer *parent) override;
     QPlatformCamera *createCamera(QCamera *camera) override;
     QPlatformMediaEncoder *createEncoder(QMediaEncoder *encoder) override;
diff --git a/tests/auto/integration/qaudiodecoderbackend/tst_qaudiodecoderbackend.cpp b/tests/auto/integration/qaudiodecoderbackend/tst_qaudiodecoderbackend.cpp
index a59bd1701..b3ccb0a10 100644
--- a/tests/auto/integration/qaudiodecoderbackend/tst_qaudiodecoderbackend.cpp
+++ b/tests/auto/integration/qaudiodecoderbackend/tst_qaudiodecoderbackend.cpp
@@ -107,10 +107,11 @@ void tst_QAudioDecoderBackend::fileTest()
 
     // Test local file
     QFileInfo fileInfo(QFINDTESTDATA(TEST_FILE_NAME));
-    d.setSource(fileInfo.absoluteFilePath());
+    QUrl url = QUrl::fromLocalFile(fileInfo.absoluteFilePath());
+    d.setSource(url);
     QVERIFY(d.state() == QAudioDecoder::StoppedState);
     QVERIFY(!d.bufferAvailable());
-    QCOMPARE(d.source(), fileInfo.absoluteFilePath());
+    QCOMPARE(d.source(), url);
 
     QSignalSpy readySpy(&d, SIGNAL(bufferReady()));
     QSignalSpy bufferChangedSpy(&d, SIGNAL(bufferAvailableChanged(bool)));
@@ -284,10 +285,11 @@ void tst_QAudioDecoderBackend::unsupportedFileTest()
 
     // Test local file
     QFileInfo fileInfo(QFINDTESTDATA(TEST_UNSUPPORTED_FILE_NAME));
-    d.setSource(fileInfo.absoluteFilePath());
+    QUrl url = QUrl::fromLocalFile(fileInfo.absoluteFilePath());
+    d.setSource(url);
     QVERIFY(d.state() == QAudioDecoder::StoppedState);
     QVERIFY(!d.bufferAvailable());
-    QCOMPARE(d.source(), fileInfo.absoluteFilePath());
+    QCOMPARE(d.source(), url);
 
     QSignalSpy readySpy(&d, SIGNAL(bufferReady()));
     QSignalSpy bufferChangedSpy(&d, SIGNAL(bufferAvailableChanged(bool)));
@@ -357,15 +359,16 @@ void tst_QAudioDecoderBackend::corruptedFileTest()
 
     QVERIFY(d.state() == QAudioDecoder::StoppedState);
     QVERIFY(d.bufferAvailable() == false);
-    QCOMPARE(d.source(), QString(""));
+    QCOMPARE(d.source(), QUrl());
     QVERIFY(d.audioFormat() == QAudioFormat());
 
     // Test local file
     QFileInfo fileInfo(QFINDTESTDATA(TEST_CORRUPTED_FILE_NAME));
-    d.setSource(fileInfo.absoluteFilePath());
+    QUrl url = QUrl::fromLocalFile(fileInfo.absoluteFilePath());
+    d.setSource(url);
     QVERIFY(d.state() == QAudioDecoder::StoppedState);
     QVERIFY(!d.bufferAvailable());
-    QCOMPARE(d.source(), fileInfo.absoluteFilePath());
+    QCOMPARE(d.source(), url);
 
     QSignalSpy readySpy(&d, SIGNAL(bufferReady()));
     QSignalSpy bufferChangedSpy(&d, SIGNAL(bufferAvailableChanged(bool)));
diff --git a/tests/auto/unit/mockbackend/qmockaudiodecoder.h b/tests/auto/unit/mockbackend/qmockaudiodecoder.h
index 1e1dca514..24cd98756 100644
--- a/tests/auto/unit/mockbackend/qmockaudiodecoder.h
+++ b/tests/auto/unit/mockbackend/qmockaudiodecoder.h
@@ -47,7 +47,7 @@ class QMockAudioDecoder : public QPlatformAudioDecoder
     Q_OBJECT
 
 public:
-    QMockAudioDecoder(QObject *parent = 0)
+    QMockAudioDecoder(QAudioDecoder *parent = 0)
         : QPlatformAudioDecoder(parent)
         , mState(QAudioDecoder::StoppedState)
         , mDevice(0)
diff --git a/tests/auto/unit/mockbackend/qmockintegration.cpp b/tests/auto/unit/mockbackend/qmockintegration.cpp
index 698ecfed9..a9135f175 100644
--- a/tests/auto/unit/mockbackend/qmockintegration.cpp
+++ b/tests/auto/unit/mockbackend/qmockintegration.cpp
@@ -66,12 +66,12 @@ QPlatformMediaDevices *QMockIntegration::devices()
     return m_devices;
 }
 
-QPlatformAudioDecoder *QMockIntegration::createAudioDecoder()
+QPlatformAudioDecoder *QMockIntegration::createAudioDecoder(QAudioDecoder *decoder)
 {
     if (m_flags & NoAudioDecoderInterface)
         m_lastAudioDecoderControl = nullptr;
     else
-        m_lastAudioDecoderControl = new QMockAudioDecoder;
+        m_lastAudioDecoderControl = new QMockAudioDecoder(decoder);
     return m_lastAudioDecoderControl;
 }
 
diff --git a/tests/auto/unit/mockbackend/qmockintegration_p.h b/tests/auto/unit/mockbackend/qmockintegration_p.h
index 11ca8eccc..d0c14523d 100644
--- a/tests/auto/unit/mockbackend/qmockintegration_p.h
+++ b/tests/auto/unit/mockbackend/qmockintegration_p.h
@@ -71,7 +71,7 @@ public:
     QPlatformMediaDevices *devices() override;
     QPlatformMediaFormatInfo *formatInfo() override { return nullptr; }
 
-    QPlatformAudioDecoder *createAudioDecoder() override;
+    QPlatformAudioDecoder *createAudioDecoder(QAudioDecoder *decoder) override;
     QPlatformMediaPlayer *createPlayer(QMediaPlayer *) override;
     QPlatformCamera *createCamera(QCamera *) override;
     QPlatformMediaEncoder *createEncoder(QMediaEncoder *) override;