Progressive download in Phonon MMF backend: integrated with player

This commit integrates the Download class with the media playback
classes in the backend, to implement Progressive Download.

Note that this PDL implementation has one drawback: when video
playback is paused due to shortage of data (i.e. due to the download
being temporarily stalled), the display goes black.  This is because,
when the end of the currently-downloaded data is reached, the
playback session is closed.  When more data becomes available, the
clip is re-opened, a seek is done to reach the previous playback
position, and playback is re-started.  Closing the playback session
closes the video stack's connection to the display, thereby causing
the video widget to go black while more data is buffered.

This is a consequence of the level in the native video stack at which
the Phonon integration is done: managing a network stall without
requiring the playback session to be closed would require integration
below the MMF client API, specifically at the MMF controller level.

Task-number: QTBUG-10769
Reviewed-by: Derick Hawcroft

Author: Gareth Stockwell

src/3rdparty/phonon/mmf/abstractmediaplayer.cpp

@@ -51,10 +51,13 @@ MMF::AbstractMediaPlayer::AbstractMediaPlayer
         ,   m_parent(parent)
         ,   m_pending(NothingPending)
         ,   m_positionTimer(new QTimer(this))
+        ,   m_position(0)
         ,   m_bufferStatusTimer(new QTimer(this))
         ,   m_mmfMaxVolume(NullMaxVolume)
         ,   m_prefinishMarkSent(false)
         ,   m_aboutToFinishSent(false)
+        ,   m_download(0)
+        ,   m_downloadStalled(false)
 {
     connect(m_positionTimer.data(), SIGNAL(timeout()), this, SLOT(positionTick()));
     connect(m_bufferStatusTimer.data(), SIGNAL(timeout()), this, SLOT(bufferStatusTick()));
@@ -183,6 +186,7 @@ void MMF::AbstractMediaPlayer::seek(qint64 ms)
         }
 
         doSeek(ms);
+        m_position = ms;
         resetMarksIfRewound();
 
         if(wasPlaying && state() != ErrorState) {
@@ -207,6 +211,11 @@ bool MMF::AbstractMediaPlayer::isSeekable() const
     return true;
 }
 
+qint64 MMF::AbstractMediaPlayer::currentTime() const
+{
+    return m_position;
+}
+
 void MMF::AbstractMediaPlayer::doSetTickInterval(qint32 interval)
 {
     TRACE_CONTEXT(AbstractMediaPlayer::doSetTickInterval, EAudioApi);
@@ -247,6 +256,14 @@ void MMF::AbstractMediaPlayer::open()
             symbianErr = openFile(*file);
             if (KErrNone != symbianErr)
                 errorMessage = tr("Error opening file");
+        } else if (url.scheme() == QLatin1String("http")) {
+            Q_ASSERT(!m_download);
+            m_download = new Download(url, this);
+            connect(m_download, SIGNAL(lengthChanged(qint64)),
+                    this, SLOT(downloadLengthChanged(qint64)));
+            connect(m_download, SIGNAL(stateChanged(Download::State)),
+                    this, SLOT(downloadStateChanged(Download::State)));
+            m_download->start();
         } else {
             symbianErr = openUrl(url.toString());
             if (KErrNone != symbianErr)
@@ -288,6 +305,14 @@ void MMF::AbstractMediaPlayer::open()
     TRACE_EXIT_0();
 }
 
+void MMF::AbstractMediaPlayer::close()
+{
+    doClose();
+    delete m_download;
+    m_download = 0;
+    m_position = 0;
+}
+
 void MMF::AbstractMediaPlayer::volumeChanged(qreal volume)
 {
     TRACE_CONTEXT(AbstractMediaPlayer::volumeChanged, EAudioInternal);
@@ -374,7 +399,8 @@ void MMF::AbstractMediaPlayer::bufferingComplete()
 {
     stopBufferStatusTimer();
     emit MMF::AbstractPlayer::bufferStatus(100);
-    changeState(m_stateBeforeBuffering);
+    if (!progressiveDownloadStalled())
+        changeState(m_stateBeforeBuffering);
 }
 
 void MMF::AbstractMediaPlayer::maxVolumeChanged(int mmfMaxVolume)
@@ -385,13 +411,28 @@ void MMF::AbstractMediaPlayer::maxVolumeChanged(int mmfMaxVolume)
 
 void MMF::AbstractMediaPlayer::loadingComplete(int error)
 {
-    Q_ASSERT(Phonon::LoadingState == state());
-
-    if (KErrNone == error) {
-        updateMetaData();
-        changeState(StoppedState);
+    TRACE_CONTEXT(AbstractMediaPlayer::loadingComplete, EAudioApi);
+    TRACE_ENTRY("state %d error %d", state(), error);
+    if (progressiveDownloadStalled()) {
+        Q_ASSERT(Phonon::BufferingState == state());
+        if (KErrNone == error) {
+            bufferingComplete();
+            doSeek(m_position);
+            startPlayback();
+            m_downloadStalled = false;
+        }
     } else {
-        setError(tr("Loading clip failed"), error);
+        Q_ASSERT(Phonon::LoadingState == state());
+        if (KErrNone == error) {
+            updateMetaData();
+            changeState(StoppedState);
+        } else {
+            if (isProgressiveDownload() && KErrCorrupt == error) {
+                setProgressiveDownloadStalled();
+            } else {
+                setError(tr("Loading clip failed"), error);
+            }
+        }
     }
 }
 
@@ -415,8 +456,12 @@ void MMF::AbstractMediaPlayer::playbackComplete(int error)
         QMetaObject::invokeMethod(m_parent, "switchToNextSource", Qt::QueuedConnection);
     }
     else {
-        setError(tr("Playback complete"), error);
-        emit finished();
+        if (isProgressiveDownload() && KErrCorrupt == error) {
+            setProgressiveDownloadStalled();
+        } else {
+            setError(tr("Playback complete"), error);
+            emit finished();
+        }
     }
 }
 
@@ -425,15 +470,28 @@ qint64 MMF::AbstractMediaPlayer::toMilliSeconds(const TTimeIntervalMicroSeconds
     return in.Int64() / 1000;
 }
 
+bool MMF::AbstractMediaPlayer::isProgressiveDownload() const
+{
+    return (0 != m_download);
+}
+
+bool MMF::AbstractMediaPlayer::progressiveDownloadStalled() const
+{
+    return m_downloadStalled;
+}
+
 //-----------------------------------------------------------------------------
 // Slots
 //-----------------------------------------------------------------------------
 
 void MMF::AbstractMediaPlayer::positionTick()
 {
-    const qint64 current = currentTime();
-    emitMarksIfReached(current);
-    emit MMF::AbstractPlayer::tick(current);
+    const qint64 pos = getCurrentTime();
+    if (pos > m_position) {
+        m_position = pos;
+        emitMarksIfReached(m_position);
+        emit MMF::AbstractPlayer::tick(m_position);
+    }
 }
 
 void MMF::AbstractMediaPlayer::emitMarksIfReached(qint64 current)
@@ -458,7 +516,7 @@ void MMF::AbstractMediaPlayer::emitMarksIfReached(qint64 current)
 
 void MMF::AbstractMediaPlayer::resetMarksIfRewound()
 {
-    const qint64 current = currentTime();
+    const qint64 current = getCurrentTime();
     const qint64 total = totalTime();
     const qint64 remaining = total - current;
 
@@ -487,9 +545,71 @@ void MMF::AbstractMediaPlayer::startPlayback()
     changeState(PlayingState);
 }
 
+void MMF::AbstractMediaPlayer::setProgressiveDownloadStalled()
+{
+    TRACE_CONTEXT(AbstractMediaPlayer::setProgressiveDownloadStalled, EAudioApi);
+    TRACE_ENTRY("state %d", state());
+    Q_ASSERT(isProgressiveDownload());
+    m_downloadStalled = true;
+    doClose();
+    bufferingStarted();
+    // Video player loses window handle when closed - need to reapply it here
+    videoOutputChanged();
+#ifdef QT_PHONON_MMF_DOWNLOAD_DUMMY
+    m_download->resume();
+#endif
+}
+
 void MMF::AbstractMediaPlayer::bufferStatusTick()
 {
-    emit MMF::AbstractPlayer::bufferStatus(bufferStatus());
+    // During progressive download, there is no way to detect the buffering status.
+    // Phonon does not support a "buffering; amount unknown" signal, therefore we
+    // return a buffering status of zero.
+    const int status = progressiveDownloadStalled() ? 0 : bufferStatus();
+    emit MMF::AbstractPlayer::bufferStatus(status);
+}
+
+void MMF::AbstractMediaPlayer::downloadLengthChanged(qint64 length)
+{
+    TRACE_CONTEXT(AbstractMediaPlayer::downloadLengthChanged, EAudioApi);
+    TRACE_ENTRY("length %Ld", length);
+    Q_UNUSED(length)
+    if (m_downloadStalled) {
+        bufferingComplete();
+        int err = m_parent->openFileHandle(m_download->targetFileName());
+        if (KErrNone == err)
+            err = openFile(*m_parent->file());
+        if (KErrNone != err)
+            setError(tr("Error opening file"));
+    }
+}
+
+void MMF::AbstractMediaPlayer::downloadStateChanged(Download::State state)
+{
+    TRACE_CONTEXT(AbstractMediaPlayer::downloadStateChanged, EAudioApi);
+    TRACE_ENTRY("state %d", state);
+    switch (state) {
+    case Download::Idle:
+    case Download::Initializing:
+        break;
+    case Download::Downloading:
+        {
+        int err = m_parent->openFileHandle(m_download->targetFileName());
+        if (KErrNone == err)
+            err = openFile(*m_parent->file());
+        else if (KErrCorrupt == err)
+            // Insufficient data downloaded - enter Buffering state
+            setProgressiveDownloadStalled();
+        if (KErrNone != err)
+            setError(tr("Error opening file"));
+        }
+        break;
+    case Download::Complete:
+        break;
+    case Download::Error:
+        setError(tr("Download error"));
+        break;
+    }
 }
 
 Phonon::State MMF::AbstractMediaPlayer::phononState(PrivateState state) const

src/3rdparty/phonon/mmf/abstractmediaplayer.h

@@ -23,6 +23,7 @@ along with this library.  If not, see <http://www.gnu.org/licenses/>.
 #include <QScopedPointer>
 #include <e32std.h>
 #include "abstractplayer.h"
+#include "download.h"
 
 class RFile;
 
@@ -48,13 +49,15 @@ class AbstractMediaPlayer : public AbstractPlayer
 
 public:
     virtual void open();
+    virtual void close();
 
     // MediaObjectInterface
     virtual void play();
     virtual void pause();
     virtual void stop();
     virtual void seek(qint64 milliseconds);
     virtual bool isSeekable() const;
+    virtual qint64 currentTime() const;
     virtual void volumeChanged(qreal volume);
 
 protected:
@@ -68,12 +71,15 @@ class AbstractMediaPlayer : public AbstractPlayer
     virtual void doStop() = 0;
     virtual void doSeek(qint64 pos) = 0;
     virtual int setDeviceVolume(int mmfVolume) = 0;
+    virtual int openFile(const QString &fileName) = 0;
     virtual int openFile(RFile& file) = 0;
     virtual int openUrl(const QString& url) = 0;
     virtual int openDescriptor(const TDesC8 &des) = 0;
     virtual int bufferStatus() const = 0;
+    virtual void doClose() = 0;
 
     void updateMetaData();
+    virtual qint64 getCurrentTime() const = 0;
     virtual int numberOfMetaDataEntries() const = 0;
     virtual QPair<QString, QString> metaDataEntry(int index) const = 0;
 
@@ -86,6 +92,9 @@ class AbstractMediaPlayer : public AbstractPlayer
 
     static qint64 toMilliSeconds(const TTimeIntervalMicroSeconds &);
 
+    bool isProgressiveDownload() const;
+    bool progressiveDownloadStalled() const;
+
 private:
     void startPositionTimer();
     void stopPositionTimer();
@@ -96,6 +105,7 @@ class AbstractMediaPlayer : public AbstractPlayer
     void emitMarksIfReached(qint64 position);
     void resetMarksIfRewound();
     void startPlayback();
+    void setProgressiveDownloadStalled();
 
     enum Pending {
         NothingPending,
@@ -108,13 +118,16 @@ class AbstractMediaPlayer : public AbstractPlayer
 private Q_SLOTS:
     void positionTick();
     void bufferStatusTick();
+    void downloadLengthChanged(qint64);
+    void downloadStateChanged(Download::State);
 
 private:
     MediaObject *const          m_parent;
 
     Pending                     m_pending;
 
     QScopedPointer<QTimer>      m_positionTimer;
+    qint64                      m_position;
 
     QScopedPointer<QTimer>      m_bufferStatusTimer;
     PrivateState                m_stateBeforeBuffering;
@@ -127,6 +140,10 @@ private Q_SLOTS:
     // Used for playback of resource files
     TPtrC8                      m_buffer;
 
+    // Used for progressive download
+    Download                    *m_download;
+    bool                        m_downloadStalled;
+
     QMultiMap<QString, QString> m_metaData;
 
 };

src/3rdparty/phonon/mmf/abstractvideoplayer.cpp

@@ -16,6 +16,7 @@ along with this library.  If not, see <http://www.gnu.org/licenses/>.
 
 */
 
+#include <QDir>
 #include <QUrl>
 #include <QTimer>
 #include <QWidget>
@@ -132,6 +133,13 @@ int MMF::AbstractVideoPlayer::setDeviceVolume(int mmfVolume)
     return err;
 }
 
+int MMF::AbstractVideoPlayer::openFile(const QString &fileName)
+{
+    const QHBufC nativeFileName(QDir::toNativeSeparators(fileName));
+    TRAPD(err, m_player->OpenFileL(*nativeFileName));
+    return err;
+}
+
 int MMF::AbstractVideoPlayer::openFile(RFile &file)
 {
     TRAPD(err, m_player->OpenFileL(file));
@@ -157,7 +165,7 @@ int MMF::AbstractVideoPlayer::bufferStatus() const
     return result;
 }
 
-void MMF::AbstractVideoPlayer::close()
+void MMF::AbstractVideoPlayer::doClose()
 {
     m_player->Close();
 }
@@ -167,9 +175,9 @@ bool MMF::AbstractVideoPlayer::hasVideo() const
     return true;
 }
 
-qint64 MMF::AbstractVideoPlayer::currentTime() const
+qint64 MMF::AbstractVideoPlayer::getCurrentTime() const
 {
-    TRACE_CONTEXT(AbstractVideoPlayer::currentTime, EVideoApi);
+    TRACE_CONTEXT(AbstractVideoPlayer::getCurrentTime, EVideoApi);
 
     TTimeIntervalMicroSeconds us;
     TRAPD(err, us = m_player->PositionL())
@@ -246,7 +254,9 @@ void MMF::AbstractVideoPlayer::MvpuoOpenComplete(TInt aError)
     TRACE_CONTEXT(AbstractVideoPlayer::MvpuoOpenComplete, EVideoApi);
     TRACE_ENTRY("state %d error %d", state(), aError);
 
-    __ASSERT_ALWAYS(LoadingState == state(), Utils::panic(InvalidStatePanic));
+    __ASSERT_ALWAYS(LoadingState == state() ||
+                    progressiveDownloadStalled() && BufferingState == state(),
+                    Utils::panic(InvalidStatePanic));
 
     if (KErrNone == aError)
         m_player->Prepare();
@@ -261,7 +271,9 @@ void MMF::AbstractVideoPlayer::MvpuoPrepareComplete(TInt aError)
     TRACE_CONTEXT(AbstractVideoPlayer::MvpuoPrepareComplete, EVideoApi);
     TRACE_ENTRY("state %d error %d", state(), aError);
 
-    __ASSERT_ALWAYS(LoadingState == state(), Utils::panic(InvalidStatePanic));
+    __ASSERT_ALWAYS(LoadingState == state() ||
+                    progressiveDownloadStalled() && BufferingState == state(),
+                    Utils::panic(InvalidStatePanic));
 
     TRAPD(err, getVideoClipParametersL(aError));
 
@@ -470,7 +482,7 @@ void MMF::AbstractVideoPlayer::updateScaleFactors(const QSize &windowSize, bool
 
 void MMF::AbstractVideoPlayer::parametersChanged(VideoParameters parameters)
 {
-    if (state() == LoadingState)
+    if (state() == LoadingState || progressiveDownloadStalled() && BufferingState == state())
         m_pendingChanges |= parameters;
     else
         handleParametersChanged(parameters);