Cleanup the QMediaEncoder backend architecture

QPlatformMediaEncoder should not be a QObject, as with the
other backend classes. Instead, the class now tracks some
state to simplify the implementation of the platform dependent
code and emits the signals for the frontend.

Change-Id: Iec45638de4333cb9e88f89c448194b49a5de0e1e
Reviewed-by: André de la Rocha <andre.rocha@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

17 files changed, 177 insertions, 206 deletions

diff --git a/src/multimedia/camera/qcamerainfo.cpp b/src/multimedia/camera/qcamerainfo.cpp
index 6e7020590..a8d2bbb42 100644
--- a/src/multimedia/camera/qcamerainfo.cpp
+++ b/src/multimedia/camera/qcamerainfo.cpp
@@ -81,6 +81,8 @@ bool QCameraFormat::operator==(const QCameraFormat &other) const
 {
     if (d == other.d)
         return true;
+    if (!d || !other.d)
+        return false;
     return d->pixelFormat == other.d->pixelFormat &&
            d->minFrameRate == other.d->minFrameRate &&
            d->maxFrameRate == other.d->maxFrameRate &&
diff --git a/src/multimedia/platform/android/mediacapture/qandroidcapturesession_p.h b/src/multimedia/platform/android/mediacapture/qandroidcapturesession_p.h
index 48ed72201..4bb0c06f7 100644
--- a/src/multimedia/platform/android/mediacapture/qandroidcapturesession_p.h
+++ b/src/multimedia/platform/android/mediacapture/qandroidcapturesession_p.h
@@ -58,6 +58,7 @@
 #include <qtimer.h>
 #include <private/qmediastoragelocation_p.h>
 #include "androidmediarecorder_p.h"
+#include "qandroidmediaencoder_p.h"
 
 QT_BEGIN_NAMESPACE
 
@@ -89,15 +90,37 @@ public:
     void setEncoderSettings(const QMediaEncoderSettings &settings);
     QMediaEncoderSettings encoderSettings() { return m_encoderSettings; }
 
+    void setMediaEncoder(QAndroidMediaEncoder *encoder) { m_mediaEncoder = encoder; }
+
     void applySettings();
 
+    void stateChanged(QMediaEncoder::State state) {
+        if (m_mediaEncoder)
+            m_mediaEncoder->stateChanged(state);
+    }
+    void statusChanged(QMediaEncoder::Status status)
+    {
+        if (m_mediaEncoder)
+            m_mediaEncoder->statusChanged(status);
+    }
+    void durationChanged(qint64 position)
+    {
+        if (m_mediaEncoder)
+            m_mediaEncoder->durationChanged(position);
+    }
+    void actualLocationChanged(const QUrl &location)
+    {
+        if (m_mediaEncoder)
+            m_mediaEncoder->actualLocationChanged(location);
+    }
+    void error(int error, const QString &errorString)
+    {
+        if (m_mediaEncoder)
+            m_mediaEncoder->error(QMediaEncoder::Error(error), errorString);
+    }
+
 Q_SIGNALS:
     void audioInputChanged(const QString& name);
-    void stateChanged(QMediaEncoder::State state);
-    void statusChanged(QMediaEncoder::Status status);
-    void durationChanged(qint64 position);
-    void actualLocationChanged(const QUrl &location);
-    void error(int error, const QString &errorString);
 
 private Q_SLOTS:
     void updateDuration();
@@ -148,6 +171,7 @@ private:
     void updateResolution();
     void restartViewfinder();
 
+    QAndroidMediaEncoder *m_mediaEncoder = nullptr;
     AndroidMediaRecorder *m_mediaRecorder;
     QAndroidCameraSession *m_cameraSession;
 
diff --git a/src/multimedia/platform/android/mediacapture/qandroidmediaencoder.cpp b/src/multimedia/platform/android/mediacapture/qandroidmediaencoder.cpp
index d26a6167c..90fbd0ac2 100644
--- a/src/multimedia/platform/android/mediacapture/qandroidmediaencoder.cpp
+++ b/src/multimedia/platform/android/mediacapture/qandroidmediaencoder.cpp
@@ -105,12 +105,7 @@ void QAndroidMediaEncoder::setCaptureSession(QPlatformMediaCaptureSession *sessi
     }
     m_session = m_service->captureSession();
     Q_ASSERT(m_session);
-
-    connect(m_session, SIGNAL(stateChanged(QMediaEncoder::State)), this, SIGNAL(stateChanged(QMediaEncoder::State)));
-    connect(m_session, SIGNAL(statusChanged(QMediaEncoder::Status)), this, SIGNAL(statusChanged(QMediaEncoder::Status)));
-    connect(m_session, SIGNAL(durationChanged(qint64)), this, SIGNAL(durationChanged(qint64)));
-    connect(m_session, SIGNAL(actualLocationChanged(QUrl)), this, SIGNAL(actualLocationChanged(QUrl)));
-    connect(m_session, SIGNAL(error(int,QString)), this, SIGNAL(error(int,QString)));
+    m_session->setMediaEncoder(this);
 }
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/android/mediacapture/qandroidmediaencoder_p.h b/src/multimedia/platform/android/mediacapture/qandroidmediaencoder_p.h
index b87da75cf..35c6c0749 100644
--- a/src/multimedia/platform/android/mediacapture/qandroidmediaencoder_p.h
+++ b/src/multimedia/platform/android/mediacapture/qandroidmediaencoder_p.h
@@ -61,7 +61,6 @@ class QAndroidCaptureService;
 
 class QAndroidMediaEncoder : public QPlatformMediaEncoder
 {
-    Q_OBJECT
 public:
     explicit QAndroidMediaEncoder(QMediaEncoder *parent);
 
@@ -76,10 +75,11 @@ public:
 
     void setCaptureSession(QPlatformMediaCaptureSession *session);
 
-public Q_SLOTS:
     void setState(QMediaEncoder::State state) override;
 
 private:
+    friend class QAndroidCaptureSession;
+
     QAndroidCaptureSession *m_session = nullptr;
     QAndroidCaptureService *m_service = nullptr;
 };
diff --git a/src/multimedia/platform/darwin/camera/avfmediaencoder.mm b/src/multimedia/platform/darwin/camera/avfmediaencoder.mm
index 93bbf95af..330602173 100644
--- a/src/multimedia/platform/darwin/camera/avfmediaencoder.mm
+++ b/src/multimedia/platform/darwin/camera/avfmediaencoder.mm
@@ -86,7 +86,8 @@ bool qt_file_exists(NSURL *fileURL)
 }
 
 AVFMediaEncoder::AVFMediaEncoder(QMediaEncoder *parent)
-    : QPlatformMediaEncoder(parent)
+    : QObject(parent)
+    , QPlatformMediaEncoder(parent)
     , m_state(QMediaEncoder::StoppedState)
     , m_lastStatus(QMediaEncoder::StoppedStatus)
     , m_audioSettings(nil)
diff --git a/src/multimedia/platform/darwin/camera/avfmediaencoder_p.h b/src/multimedia/platform/darwin/camera/avfmediaencoder_p.h
index d8434e176..8e6893a65 100644
--- a/src/multimedia/platform/darwin/camera/avfmediaencoder_p.h
+++ b/src/multimedia/platform/darwin/camera/avfmediaencoder_p.h
@@ -70,7 +70,7 @@ class AVFCameraService;
 class QString;
 class QUrl;
 
-class AVFMediaEncoder : public QPlatformMediaEncoder
+class AVFMediaEncoder : public QObject, public QPlatformMediaEncoder
 {
     Q_OBJECT
 public:
diff --git a/src/multimedia/platform/gstreamer/common/qgstutils.cpp b/src/multimedia/platform/gstreamer/common/qgstutils.cpp
index 8c85219d8..7dd733f00 100644
--- a/src/multimedia/platform/gstreamer/common/qgstutils.cpp
+++ b/src/multimedia/platform/gstreamer/common/qgstutils.cpp
@@ -293,6 +293,8 @@ QGstMutableCaps QGstMutableCaps::fromCameraFormat(const QCameraFormat &format)
                                       nullptr);
     } else {
         int index = indexOfVideoFormat(format.pixelFormat());
+        if (index < 0)
+            return QGstMutableCaps();
         auto gstFormat = qt_videoFormatLookup[index].gstFormat;
         structure = gst_structure_new("video/x-raw",
                                       "format"   , G_TYPE_STRING, gst_video_format_to_string(gstFormat),
diff --git a/src/multimedia/platform/gstreamer/mediacapture/qgstreamercamera.cpp b/src/multimedia/platform/gstreamer/mediacapture/qgstreamercamera.cpp
index 1b837bd8a..e31c8e6f2 100644
--- a/src/multimedia/platform/gstreamer/mediacapture/qgstreamercamera.cpp
+++ b/src/multimedia/platform/gstreamer/mediacapture/qgstreamercamera.cpp
@@ -89,7 +89,7 @@ void QGstreamerCamera::setCamera(const QCameraInfo &camera)
 {
     if (m_cameraInfo == camera)
         return;
-    qDebug() << "setCamera" << camera;
+//    qDebug() << "setCamera" << camera;
 
     m_cameraInfo = camera;
 
@@ -141,18 +141,23 @@ void QGstreamerCamera::setCameraFormatInternal(const QCameraFormat &format)
     gstCameraBin.remove(gstDecode);
 
     if (f.pixelFormat() == QVideoFrameFormat::Format_Jpeg) {
-        qDebug() << "    enabling jpeg decoder";
+//        qDebug() << "    enabling jpeg decoder";
         gstDecode = QGstElement("jpegdec");
     } else {
-        qDebug() << "    camera delivers raw video";
+//        qDebug() << "    camera delivers raw video";
         gstDecode = QGstElement("identity");
     }
     gstCameraBin.add(gstDecode);
     gstDecode.link(gstVideoConvert);
 
     auto caps = QGstMutableCaps::fromCameraFormat(f);
-    if (!gstCamera.linkFiltered(gstDecode, caps))
-        qWarning() << "linking failed";
+    if (!caps.isNull()) {
+        if (!gstCamera.linkFiltered(gstDecode, caps))
+            qWarning() << "linking filtered camera to decoder failed" << gstCamera.name() << gstDecode.name() << caps.toString();
+    } else {
+        if (!gstCamera.link(gstDecode))
+            qWarning() << "linking camera to decoder failed" << gstCamera.name() << gstDecode.name();
+    }
 }
 
 bool QGstreamerCamera::setCameraFormat(const QCameraFormat &format)
diff --git a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp
index fc26f4097..7b12e6dcb 100644
--- a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp
+++ b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder.cpp
@@ -57,9 +57,7 @@
 Q_LOGGING_CATEGORY(qLcMediaEncoder, "qt.multimedia.encoder")
 
 QGstreamerMediaEncoder::QGstreamerMediaEncoder(QMediaEncoder *parent)
-  : QPlatformMediaEncoder(parent),
-    m_state(QMediaEncoder::StoppedState),
-    m_status(QMediaEncoder::StoppedStatus)
+  : QPlatformMediaEncoder(parent)
 {
     gstEncoder = QGstElement("encodebin", "encodebin");
     gstFileSink = QGstElement("filesink", "filesink");
@@ -84,17 +82,6 @@ bool QGstreamerMediaEncoder::setOutputLocation(const QUrl &sink)
     return true;
 }
 
-
-QMediaEncoder::State QGstreamerMediaEncoder::state() const
-{
-    return m_state;
-}
-
-QMediaEncoder::Status QGstreamerMediaEncoder::status() const
-{
-    return m_status;
-}
-
 void QGstreamerMediaEncoder::updateStatus()
 {
     static QMediaEncoder::Status statusTable[3][3] = {
@@ -108,8 +95,8 @@ void QGstreamerMediaEncoder::updateStatus()
 
     QMediaEncoder::State sessionState = QMediaEncoder::StoppedState;
 
-    auto state = gstEncoder.isNull() ? GST_STATE_NULL : gstEncoder.state();
-    switch (state) {
+    auto gstState = gstEncoder.isNull() ? GST_STATE_NULL : gstEncoder.state();
+    switch (gstState) {
     case GST_STATE_PLAYING:
         sessionState = QMediaEncoder::RecordingState;
         break;
@@ -121,18 +108,15 @@ void QGstreamerMediaEncoder::updateStatus()
         break;
     }
 
-    auto newStatus = statusTable[m_state][sessionState];
+    auto newStatus = statusTable[state()][sessionState];
 
-    if (m_status != newStatus) {
-        m_status = newStatus;
-        qCDebug(qLcMediaEncoder) << "updateStatus" << m_status;
-        emit statusChanged(m_status);
-    }
+    qCDebug(qLcMediaEncoder) << "updateStatus" << newStatus;
+    statusChanged(newStatus);
 }
 
-void QGstreamerMediaEncoder::handleSessionError(int code, const QString &description)
+void QGstreamerMediaEncoder::handleSessionError(QMediaEncoder::Error code, const QString &description)
 {
-    emit error(code, description);
+    error(code, description);
     stop();
 }
 
@@ -169,7 +153,7 @@ bool QGstreamerMediaEncoder::processBusMessage(const QGstreamerMessage &message)
         GError *err;
         gchar *debug;
         gst_message_parse_error(gm, &err, &debug);
-        emit error(int(QMediaEncoder::ResourceError), QString::fromUtf8(err->message));
+        error(QMediaEncoder::ResourceError, QString::fromUtf8(err->message));
         g_error_free(err);
         g_free(debug);
     }
@@ -182,8 +166,7 @@ bool QGstreamerMediaEncoder::processBusMessage(const QGstreamerMessage &message)
             GstState    pending;
             gst_message_parse_state_changed(gm, &oldState, &newState, &pending);
 
-            if (newState == GST_STATE_PAUSED &&
-                !m_metaData.isEmpty())
+            if (newState == GST_STATE_PAUSED && !m_metaData.isEmpty())
                 setMetaData(m_metaData);
             updateStatus();
             break;
@@ -197,7 +180,7 @@ bool QGstreamerMediaEncoder::processBusMessage(const QGstreamerMessage &message)
 
 void QGstreamerMediaEncoder::updateDuration()
 {
-    emit durationChanged(m_duration.elapsed());
+    durationChanged(m_duration.elapsed());
 }
 
 qint64 QGstreamerMediaEncoder::duration() const
@@ -281,13 +264,12 @@ static GstEncodingContainerProfile *createEncodingProfile(const QMediaEncoderSet
     return containerProfile;
 }
 
-void QGstreamerMediaEncoder::setState(QMediaEncoder::State state)
+void QGstreamerMediaEncoder::setState(QMediaEncoder::State s)
 {
-    if (state == m_state)
+    if (s == state())
         return;
 
-    m_state = state;
-    switch (state) {
+    switch (s) {
     case QMediaEncoder::StoppedState:
         stop();
         break;
@@ -298,16 +280,17 @@ void QGstreamerMediaEncoder::setState(QMediaEncoder::State state)
         record();
         break;
     }
-    emit stateChanged(m_state);
+    stateChanged(s);
 }
 
 void QGstreamerMediaEncoder::record()
 {
     if (!m_session)
         return;
-    if (m_state == QMediaEncoder::PausedState) {
+    if (state() == QMediaEncoder::PausedState) {
         // coming from paused state
         gstEncoder.setState(GST_STATE_PLAYING);
+        updateStatus();
         return;
     }
 
@@ -346,7 +329,9 @@ void QGstreamerMediaEncoder::record()
     m_duration.start();
     heartbeat.start();
     gstPipeline.dumpGraph("recording");
-    emit actualLocationChanged(m_outputLocation);
+
+    actualLocationChanged(m_outputLocation);
+    updateStatus();
 }
 
 void QGstreamerMediaEncoder::pause()
@@ -357,7 +342,7 @@ void QGstreamerMediaEncoder::pause()
     gstPipeline.dumpGraph("before-pause");
     gstEncoder.setState(GST_STATE_PAUSED);
 
-    emit stateChanged(m_state);
+    stateChanged(QMediaRecorder::PausedState);
     updateStatus();
 }
 
@@ -381,6 +366,8 @@ void QGstreamerMediaEncoder::stop()
     qCDebug(qLcMediaEncoder) << ">>>>>>>>>>>>> sending EOS";
 
     gstEncoder.sendEos();
+    stateChanged(QMediaEncoder::StoppedState);
+    updateStatus();
 }
 
 void QGstreamerMediaEncoder::finalize()
@@ -400,11 +387,6 @@ void QGstreamerMediaEncoder::finalize()
     updateStatus();
 }
 
-void QGstreamerMediaEncoder::updateSettings()
-{
-    applySettings();
-}
-
 void QGstreamerMediaEncoder::applySettings()
 {
     if (!m_session)
@@ -448,7 +430,8 @@ void QGstreamerMediaEncoder::setCaptureSession(QPlatformMediaCaptureSession *ses
         gstFileSink.setStateSync(GST_STATE_NULL);
         gstPipeline.remove(gstEncoder);
         gstPipeline.remove(gstFileSink);
-        disconnect(&heartbeat, nullptr, this, nullptr);
+        heartbeat.disconnect();
+        QObject::disconnect(cameraChanged);
     }
 
     m_session = captureSession;
@@ -461,7 +444,7 @@ void QGstreamerMediaEncoder::setCaptureSession(QPlatformMediaCaptureSession *ses
 
     // used to update duration every second
     heartbeat.setInterval(1000);
-    connect(&heartbeat, &QTimer::timeout, this, &QGstreamerMediaEncoder::updateDuration);
+    QObject::connect(&heartbeat, &QTimer::timeout, [this]() { updateDuration(); });
 
     gstPipeline.add(gstEncoder, gstFileSink);
     gstEncoder.link(gstFileSink);
@@ -470,8 +453,7 @@ void QGstreamerMediaEncoder::setCaptureSession(QPlatformMediaCaptureSession *ses
 
     // ensure we have a usable format
     setEncoderSettings(QMediaEncoderSettings());
-    connect(m_session, &QGstreamerMediaCapture::cameraChanged,
-            this, &QGstreamerMediaEncoder::updateSettings);
+    cameraChanged = QObject::connect(m_session, &QGstreamerMediaCapture::cameraChanged, [this]() { applySettings(); });
 }
 
 QDir QGstreamerMediaEncoder::defaultDir() const
diff --git a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder_p.h b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder_p.h
index 9bc16c6a7..262bbdd45 100644
--- a/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder_p.h
+++ b/src/multimedia/platform/gstreamer/mediacapture/qgstreamermediaencoder_p.h
@@ -68,8 +68,6 @@ class QGstreamerMessage;
 
 class QGstreamerMediaEncoder : public QPlatformMediaEncoder, QGstreamerBusMessageFilter
 {
-    Q_OBJECT
-
 public:
     QGstreamerMediaEncoder(QMediaEncoder *parent);
     virtual ~QGstreamerMediaEncoder();
@@ -77,9 +75,6 @@ public:
     QUrl outputLocation() const override;
     bool setOutputLocation(const QUrl &sink) override;
 
-    QMediaEncoder::State state() const override;
-    QMediaEncoder::Status status() const override;
-
     qint64 duration() const override;
 
     void applySettings() override;
@@ -94,20 +89,17 @@ public:
 
 private:
     bool processBusMessage(const QGstreamerMessage& message) override;
-public slots:
+public:
     void setState(QMediaEncoder::State state) override;
     void record();
     void pause();
     void stop();
-
-private slots:
-    void updateStatus();
-    void handleSessionError(int code, const QString &description);
     void updateDuration();
-    void finalize();
-    void updateSettings();
 
 private:
+    void updateStatus();
+    void handleSessionError(QMediaEncoderBase::Error code, const QString &description);
+    void finalize();
     QDir defaultDir() const;
     QString generateFileName(const QDir &dir, const QString &ext) const;
 
@@ -116,8 +108,6 @@ private:
     QMediaEncoderSettings m_settings;
     QGstreamerMediaCapture *m_session = nullptr;
     QGstreamerMetaData m_metaData;
-    QMediaEncoder::State m_state = QMediaEncoder::StoppedState;
-    QMediaEncoder::Status m_status = QMediaEncoder::StoppedStatus;
     QElapsedTimer m_duration;
     QTimer heartbeat;
 
@@ -127,6 +117,8 @@ private:
 
     QGstPad audioSrcPad;
     QGstPad videoSrcPad;
+
+    QMetaObject::Connection cameraChanged;
 };
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/qplatformmediaencoder.cpp b/src/multimedia/platform/qplatformmediaencoder.cpp
index f5f80d1a7..944c1d944 100644
--- a/src/multimedia/platform/qplatformmediaencoder.cpp
+++ b/src/multimedia/platform/qplatformmediaencoder.cpp
@@ -66,7 +66,7 @@ QT_BEGIN_NAMESPACE
 */
 
 QPlatformMediaEncoder::QPlatformMediaEncoder(QMediaEncoder *parent)
-    : QObject(parent)
+    : q(parent)
 {
 }
 
@@ -127,37 +127,30 @@ QPlatformMediaEncoder::QPlatformMediaEncoder(QMediaEncoder *parent)
 */
 
 /*!
-    \fn void QPlatformMediaEncoder::setMuted(bool muted)
-
-    Sets the \a muted state of a media recorder.
-*/
-
-/*!
-    \fn qreal QPlatformMediaEncoder::volume() const
-
-    Returns the audio volume of a media recorder control.
-*/
-
-/*!
-    \fn void QPlatformMediaEncoder::setVolume(qreal volume)
-
-    Sets the audio \a volume of a media recorder control.
-
-    The volume is scaled linearly, ranging from \c 0 (silence) to \c 100 (full volume).
-*/
-
-/*!
     \fn void QPlatformMediaEncoder::stateChanged(QMediaRecorder::State state)
 
     Signals that the \a state of a media recorder has changed.
 */
+void QPlatformMediaEncoder::stateChanged(QMediaEncoder::State state)
+{
+    if (m_state == state)
+        return;
+    m_state = state;
+    emit q->stateChanged(state);
+}
 
 /*!
     \fn void QPlatformMediaEncoder::statusChanged(QMediaRecorder::Status status)
 
     Signals that the \a status of a media recorder has changed.
 */
-
+void QPlatformMediaEncoder::statusChanged(QMediaEncoder::Status status)
+{
+    if (m_status == status)
+        return;
+    m_status = status;
+    emit q->statusChanged(status);
+}
 
 /*!
     \fn void QPlatformMediaEncoder::durationChanged(qint64 duration)
@@ -166,18 +159,10 @@ QPlatformMediaEncoder::QPlatformMediaEncoder(QMediaEncoder *parent)
 
     This only emitted when there is a discontinuous change in the duration such as being reset to 0.
 */
-
-/*!
-    \fn void QPlatformMediaEncoder::mutedChanged(bool muted)
-
-    Signals that the \a muted state of a media recorder has changed.
-*/
-
-/*!
-    \fn void QPlatformMediaEncoder::volumeChanged(qreal gain)
-
-    Signals that the audio \a gain value has changed.
-*/
+void QPlatformMediaEncoder::durationChanged(qint64 duration)
+{
+    emit q->durationChanged(duration);
+}
 
 /*!
     \fn void QPlatformMediaEncoder::actualLocationChanged(const QUrl &location)
@@ -185,13 +170,33 @@ QPlatformMediaEncoder::QPlatformMediaEncoder(QMediaEncoder *parent)
     Signals that the actual media \a location has changed.
     This signal should be emitted at start of recording.
 */
+void QPlatformMediaEncoder::actualLocationChanged(const QUrl &location)
+{
+    if (m_actualLocation == location)
+        return;
+    m_actualLocation = location;
+    emit q->actualLocationChanged(location);
+}
 
 /*!
     \fn void QPlatformMediaEncoder::error(int error, const QString &errorString)
 
     Signals that an \a error has occurred.  The \a errorString describes the error.
 */
+void QPlatformMediaEncoder::error(QMediaEncoderBase::Error error, const QString &errorString)
+{
+    if (error == m_error && errorString == m_errorString)
+        return;
+    m_error = error;
+    m_errorString = errorString;
+    if (error != QMediaEncoder::NoError)
+        emit q->errorOccurred(error, errorString);
+    emit q->errorChanged();
+}
 
-QT_END_NAMESPACE
+void QPlatformMediaEncoder::metaDataChanged()
+{
+    emit q->metaDataChanged();
+}
 
-#include "moc_qplatformmediaencoder_p.cpp"
+QT_END_NAMESPACE
diff --git a/src/multimedia/platform/qplatformmediaencoder_p.h b/src/multimedia/platform/qplatformmediaencoder_p.h
index a891f1119..b535636bd 100644
--- a/src/multimedia/platform/qplatformmediaencoder_p.h
+++ b/src/multimedia/platform/qplatformmediaencoder_p.h
@@ -51,6 +51,8 @@
 #ifndef QPLATFORMMEDIAENCODER_H
 #define QPLATFORMMEDIAENCODER_H
 
+#include <QtCore/qurl.h>
+
 #include <QtMultimedia/qmediaencoder.h>
 #include <QtMultimedia/qmediametadata.h>
 
@@ -64,16 +66,17 @@ QT_BEGIN_NAMESPACE
 // Required for QDoc workaround
 class QString;
 
-class Q_MULTIMEDIA_EXPORT QPlatformMediaEncoder : public QObject
+class Q_MULTIMEDIA_EXPORT QPlatformMediaEncoder
 {
-    Q_OBJECT
-
 public:
+    virtual ~QPlatformMediaEncoder() {}
     virtual QUrl outputLocation() const = 0;
     virtual bool setOutputLocation(const QUrl &location) = 0;
 
-    virtual QMediaEncoder::State state() const = 0;
-    virtual QMediaEncoder::Status status() const = 0;
+    virtual QMediaEncoder::State state() const { return m_state; }
+    virtual void setState(QMediaEncoder::State state) = 0;
+
+    virtual QMediaEncoder::Status status() const { return m_status; }
 
     virtual qint64 duration() const = 0;
 
@@ -83,19 +86,30 @@ public:
     virtual void setMetaData(const QMediaMetaData &) {}
     virtual QMediaMetaData metaData() const { return {}; }
 
-Q_SIGNALS:
+    QMediaEncoder::Error error() const { return m_error;}
+    QString errorString() const { return m_errorString; }
+
+    QUrl actualLocation() const { return m_actualLocation; }
+    void clearActualLocation() { m_actualLocation.clear(); }
+    void clearError() { error(QMediaEncoder::NoError, QString()); }
+
+protected:
+    explicit QPlatformMediaEncoder(QMediaEncoder *parent);
+
     void stateChanged(QMediaEncoder::State state);
     void statusChanged(QMediaEncoder::Status status);
     void durationChanged(qint64 position);
     void actualLocationChanged(const QUrl &location);
-    void error(int error, const QString &errorString);
+    void error(QMediaEncoder::Error error, const QString &errorString);
     void metaDataChanged();
 
-public Q_SLOTS:
-    virtual void setState(QMediaEncoder::State state) = 0;
-
-protected:
-    explicit QPlatformMediaEncoder(QMediaEncoder *parent);
+private:
+    QMediaEncoder *q = nullptr;
+    QMediaEncoder::Error m_error = QMediaEncoder::NoError;
+    QString m_errorString;
+    QUrl m_actualLocation;
+    QMediaEncoder::State m_state = QMediaEncoder::StoppedState;
+    QMediaEncoder::Status m_status = QMediaEncoder::StoppedStatus;
 };
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder.cpp b/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder.cpp
index b420ed3d0..3b4c37d15 100644
--- a/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder.cpp
+++ b/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder.cpp
@@ -47,7 +47,8 @@
 QT_BEGIN_NAMESPACE
 
 QWindowsMediaEncoder::QWindowsMediaEncoder(QMediaEncoder *parent)
-    : QPlatformMediaEncoder(parent)
+    : QObject(parent),
+    QPlatformMediaEncoder(parent)
 {
 }
 
diff --git a/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder_p.h b/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder_p.h
index 0224567e7..59e6d109d 100644
--- a/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder_p.h
+++ b/src/multimedia/platform/windows/mediacapture/qwindowsmediaencoder_p.h
@@ -64,7 +64,7 @@ class QWindowsCameraSession;
 class QPlatformMediaCaptureSession;
 class QWindowsMediaCaptureService;
 
-class QWindowsMediaEncoder : public QPlatformMediaEncoder
+class QWindowsMediaEncoder : public QObject, public QPlatformMediaEncoder
 {
     Q_OBJECT
 public:
diff --git a/src/multimedia/recording/qmediaencoder.cpp b/src/multimedia/recording/qmediaencoder.cpp
index 7f48b03b1..9bb4f6696 100644
--- a/src/multimedia/recording/qmediaencoder.cpp
+++ b/src/multimedia/recording/qmediaencoder.cpp
@@ -71,40 +71,6 @@ QT_BEGIN_NAMESPACE
     \snippet multimedia-snippets/media.cpp Media encoder
 */
 
-
-#define ENUM_NAME(c,e,v) (c::staticMetaObject.enumerator(c::staticMetaObject.indexOfEnumerator(e)).valueToKey((v)))
-
-void QMediaEncoderPrivate::_q_stateChanged(QMediaEncoder::State ps)
-{
-    Q_Q(QMediaEncoder);
-
-//    qDebug() << "Encoder state changed:" << ENUM_NAME(QMediaEncoder,"State",ps);
-    if (state != ps) {
-        emit q->stateChanged(ps);
-    }
-
-    state = ps;
-}
-
-
-void QMediaEncoderPrivate::_q_error(int error, const QString &errorString)
-{
-    Q_Q(QMediaEncoder);
-
-    this->error = QMediaEncoder::Error(error);
-    this->errorString = errorString;
-
-    emit q->error(this->error);
-}
-
-void QMediaEncoderPrivate::_q_updateActualLocation(const QUrl &location)
-{
-    if (actualLocation != location) {
-        actualLocation = location;
-        emit q_func()->actualLocationChanged(actualLocation);
-    }
-}
-
 void QMediaEncoderPrivate::applySettingsLater()
 {
     if (control && !settingsChanged) {
@@ -145,6 +111,7 @@ QMediaEncoder::~QMediaEncoder()
             d_ptr->captureSession->platformSession()->setMediaEncoder(nullptr);
         d_ptr->captureSession->setEncoder(nullptr);
     }
+    delete d_ptr->control;
     delete d_ptr;
 }
 
@@ -163,29 +130,10 @@ void QMediaEncoder::setCaptureSession(QMediaCaptureSession *session)
         return;
 
     QPlatformMediaCaptureSession *platformSession = session->platformSession();
-    if (platformSession && d->control)
-        platformSession->setMediaEncoder(d->control);
-    else
+    if (!platformSession || !d->control)
         return;
 
-    connect(d->control, SIGNAL(stateChanged(QMediaEncoder::State)),
-            this, SLOT(_q_stateChanged(QMediaEncoder::State)));
-
-    connect(d->control, SIGNAL(statusChanged(QMediaEncoder::Status)),
-            this, SIGNAL(statusChanged(QMediaEncoder::Status)));
-
-    connect(d->control, SIGNAL(durationChanged(qint64)),
-            this, SIGNAL(durationChanged(qint64)));
-
-    connect(d->control, SIGNAL(actualLocationChanged(QUrl)),
-            this, SLOT(_q_updateActualLocation(QUrl)));
-
-    connect(d->control, SIGNAL(error(int,QString)),
-            this, SLOT(_q_error(int,QString)));
-
-    connect(d->control, SIGNAL(metaDataChanged()),
-            this, SIGNAL(metaDataChanged()));
-
+    platformSession->setMediaEncoder(d->control);
     d->applySettingsLater();
 
 }
@@ -230,7 +178,9 @@ QUrl QMediaEncoder::outputLocation() const
 bool QMediaEncoder::setOutputLocation(const QUrl &location)
 {
     Q_D(QMediaEncoder);
-    d->actualLocation.clear();
+    if (!d->control)
+        return false;
+    d->control->clearActualLocation();
     if (d->control && d->captureSession)
         return d->control->setOutputLocation(location);
     return false;
@@ -238,7 +188,8 @@ bool QMediaEncoder::setOutputLocation(const QUrl &location)
 
 QUrl QMediaEncoder::actualLocation() const
 {
-    return d_func()->actualLocation;
+    Q_D(const QMediaEncoder);
+    return d->control ? d->control->actualLocation() : QUrl();
 }
 
 /*!
@@ -260,7 +211,8 @@ QMediaEncoder::State QMediaEncoder::state() const
 
 QMediaEncoderBase::Status QMediaEncoder::status() const
 {
-    return d_func()->control ? QMediaEncoder::Status(d_func()->control->status()) : UnavailableStatus;
+    Q_D(const QMediaEncoder);
+    return d->control ? d->control->status() : UnavailableStatus;
 }
 
 /*!
@@ -271,7 +223,9 @@ QMediaEncoderBase::Status QMediaEncoder::status() const
 
 QMediaEncoderBase::Error QMediaEncoder::error() const
 {
-    return d_func()->error;
+    Q_D(const QMediaEncoder);
+
+    return d->control ? d->control->error() : QMediaEncoder::ResourceError;
 }
 
 /*!
@@ -282,7 +236,9 @@ QMediaEncoderBase::Error QMediaEncoder::error() const
 
 QString QMediaEncoder::errorString() const
 {
-    return d_func()->errorString;
+    Q_D(const QMediaEncoder);
+
+    return d->control ? d->control->errorString() : tr("QMediaEncoder not supported on this platform");
 }
 
 /*!
@@ -336,14 +292,14 @@ void QMediaEncoder::record()
 {
     Q_D(QMediaEncoder);
 
-    d->actualLocation.clear();
+    if (!d->control)
+        return;
+    d->control->clearActualLocation();
 
     if (d->settingsChanged)
-        d->_q_applySettings();
+        d->control->applySettings();
 
-    // reset error
-    d->error = NoError;
-    d->errorString = QString();
+    d->control->clearError();
 
     if (d->control && d->captureSession)
         d->control->setState(QMediaRecorder::RecordingState);
diff --git a/src/multimedia/recording/qmediaencoder.h b/src/multimedia/recording/qmediaencoder.h
index 570bc3373..f6f267047 100644
--- a/src/multimedia/recording/qmediaencoder.h
+++ b/src/multimedia/recording/qmediaencoder.h
@@ -106,6 +106,8 @@ class Q_MULTIMEDIA_EXPORT QMediaEncoder : public QMediaEncoderBase
     Q_PROPERTY(QUrl outputLocation READ outputLocation WRITE setOutputLocation)
     Q_PROPERTY(QUrl actualLocation READ actualLocation NOTIFY actualLocationChanged)
     Q_PROPERTY(QMediaMetaData metaData READ metaData WRITE setMetaData NOTIFY metaDataChanged)
+    Q_PROPERTY(QMediaEncoder::Error error READ error NOTIFY errorChanged)
+    Q_PROPERTY(QString errorString READ errorString NOTIFY errorChanged)
 
 public:
     QMediaEncoder(QObject *parent = nullptr);
@@ -146,7 +148,8 @@ Q_SIGNALS:
     void durationChanged(qint64 duration);
     void actualLocationChanged(const QUrl &location);
 
-    void error(QMediaEncoder::Error error);
+    void errorOccurred(QMediaEncoder::Error error, const QString &errorString);
+    void errorChanged();
 
     void metaDataChanged();
 
@@ -156,9 +159,6 @@ private:
     void setCaptureSession(QMediaCaptureSession *session);
     Q_DISABLE_COPY(QMediaEncoder)
     Q_DECLARE_PRIVATE(QMediaEncoder)
-    Q_PRIVATE_SLOT(d_func(), void _q_stateChanged(QMediaEncoder::State))
-    Q_PRIVATE_SLOT(d_func(), void _q_error(int, const QString &))
-    Q_PRIVATE_SLOT(d_func(), void _q_updateActualLocation(const QUrl &))
     Q_PRIVATE_SLOT(d_func(), void _q_applySettings())
 };
 
diff --git a/src/multimedia/recording/qmediaencoder_p.h b/src/multimedia/recording/qmediaencoder_p.h
index b2e674ac1..a2c5e4725 100644
--- a/src/multimedia/recording/qmediaencoder_p.h
+++ b/src/multimedia/recording/qmediaencoder_p.h
@@ -74,20 +74,12 @@ public:
     void applySettingsLater();
 
     QMediaCaptureSession *captureSession = nullptr;
-
     QPlatformMediaEncoder *control = nullptr;
 
     bool settingsChanged = false;
 
-    QMediaEncoder::State state = QMediaEncoder::StoppedState;
-    QMediaEncoder::Error error = QMediaEncoder::NoError;
-    QString errorString;
-    QUrl actualLocation;
     QMediaEncoderSettings encoderSettings;
 
-    void _q_stateChanged(QMediaEncoder::State state);
-    void _q_error(int error, const QString &errorString);
-    void _q_updateActualLocation(const QUrl &);
     void _q_applySettings();
 
     QMediaEncoder *q_ptr = nullptr;