Move rate handling into QGstPipeline

This makes it possible to keep state there, simplifies the API and
makes it possible to add a flush() call there that can be accessed
from outside the QGStreamerMediaPlayer class.

Change-Id: I34bbc2111b72139c9c06132ba2a6bf278e8be07d
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: André de la Rocha <andre.rocha@qt.io>

3 files changed, 47 insertions, 27 deletions

diff --git a/src/multimedia/platform/gstreamer/common/qgstpipeline_p.h b/src/multimedia/platform/gstreamer/common/qgstpipeline_p.h
index 1f4f6ee05..28ccba6e8 100644
--- a/src/multimedia/platform/gstreamer/common/qgstpipeline_p.h
+++ b/src/multimedia/platform/gstreamer/common/qgstpipeline_p.h
@@ -112,19 +112,35 @@ public:
 #endif
     }
 
+    void flush() { seek(position(), m_rate); }
+
     bool seek(qint64 pos, double rate)
     {
-        return gst_element_seek(element(), rate, GST_FORMAT_TIME,
-                                 GstSeekFlags(GST_SEEK_FLAG_FLUSH),
-                                 GST_SEEK_TYPE_SET, pos,
-                                 GST_SEEK_TYPE_SET, -1);
+        // always adjust the rate, so it can be  set before playback starts
+        // setting position needs a loaded media file that's seekable
+        m_rate = rate;
+        bool success = gst_element_seek(element(), rate, GST_FORMAT_TIME,
+                                        GstSeekFlags(GST_SEEK_FLAG_FLUSH),
+                                        GST_SEEK_TYPE_SET, pos,
+                                        GST_SEEK_TYPE_SET, -1);
+        if (!success)
+            return false;
+
+        m_position = pos;
+        return true;
     }
-    qint64 duration() const
+    bool setPlaybackRate(double rate)
     {
-        gint64 d;
-        if (!gst_element_query_duration(element(), GST_FORMAT_TIME, &d))
-            return 0.;
-        return d;
+        if (rate == m_rate)
+            return false;
+        seek(position(), rate);
+        return true;
+    }
+    double playbackRate() const { return m_rate; }
+
+    bool setPosition(qint64 pos)
+    {
+        return seek(pos, m_rate);
     }
     qint64 position() const
     {
@@ -134,7 +150,17 @@ public:
         return m_position;
     }
 
+    qint64 duration() const
+    {
+        gint64 d;
+        if (!gst_element_query_duration(element(), GST_FORMAT_TIME, &d))
+            return 0.;
+        return d;
+    }
+
+private:
     mutable qint64 m_position = 0;
+    double m_rate = 1.;
 };
 
 QT_END_NAMESPACE
diff --git a/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer.cpp b/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer.cpp
index 64786a1e8..cc6771d97 100644
--- a/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer.cpp
+++ b/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer.cpp
@@ -123,16 +123,13 @@ QMediaTimeRange QGstreamerMediaPlayer::availablePlaybackRanges() const
 
 qreal QGstreamerMediaPlayer::playbackRate() const
 {
-    return m_playbackRate;
+    return playerPipeline.playbackRate();
 }
 
 void QGstreamerMediaPlayer::setPlaybackRate(qreal rate)
 {
-    if (rate == m_playbackRate)
-        return;
-    m_playbackRate = rate;
-    playerPipeline.seek(playerPipeline.position(), m_playbackRate);
-    emit playbackRateChanged(rate);
+    if (playerPipeline.setPlaybackRate(rate))
+        playbackRateChanged(rate);
 }
 
 void QGstreamerMediaPlayer::setPosition(qint64 pos)
@@ -141,7 +138,7 @@ void QGstreamerMediaPlayer::setPosition(qint64 pos)
     if (pos == currentPos)
         return;
     playerPipeline.finishStateChange();
-    playerPipeline.seek(pos*1e6, m_playbackRate);
+    playerPipeline.setPosition(pos*1e6);
     qCDebug(qLcMediaPlayer) << Q_FUNC_INFO << pos << playerPipeline.position()/1e6;
     if (mediaStatus() == QMediaPlayer::EndOfMedia)
         mediaStatusChanged(QMediaPlayer::LoadedMedia);
@@ -155,16 +152,16 @@ void QGstreamerMediaPlayer::play()
 
     *playerPipeline.inStoppedState() = false;
     if (mediaStatus() == QMediaPlayer::EndOfMedia) {
-        playerPipeline.seek(0, m_playbackRate);
+        playerPipeline.setPosition(0);
         updatePosition();
     }
 
     qCDebug(qLcMediaPlayer) << "play().";
     int ret = playerPipeline.setState(GST_STATE_PLAYING);
     if (m_requiresSeekOnPlay) {
-        // This causes a flush of the pipeline and is required to get track changes
+        // Flushing the pipeline is required to get track changes
         // immediately, when they happen while paused.
-        playerPipeline.seek(playerPipeline.position(), m_playbackRate);
+        playerPipeline.flush();
         m_requiresSeekOnPlay = false;
     }
     if (ret == GST_STATE_CHANGE_FAILURE)
@@ -183,13 +180,13 @@ void QGstreamerMediaPlayer::pause()
     positionUpdateTimer.stop();
     if (*playerPipeline.inStoppedState()) {
         *playerPipeline.inStoppedState() = false;
-        playerPipeline.seek(playerPipeline.position(), m_playbackRate);
+        playerPipeline.flush();
     }
     int ret = playerPipeline.setState(GST_STATE_PAUSED);
     if (ret == GST_STATE_CHANGE_FAILURE)
         qCDebug(qLcMediaPlayer) << "Unable to set the pipeline to the paused state.";
     if (mediaStatus() == QMediaPlayer::EndOfMedia) {
-        playerPipeline.seek(0, m_playbackRate);
+        playerPipeline.setPosition(0);
         mediaStatusChanged(QMediaPlayer::BufferedMedia);
     }
     updatePosition();
@@ -211,7 +208,7 @@ void QGstreamerMediaPlayer::stopOrEOS(bool eos)
     if (!ret)
         qCDebug(qLcMediaPlayer) << "Unable to set the pipeline to the stopped state.";
     if (!eos)
-        playerPipeline.seek(0, m_playbackRate);
+        playerPipeline.setPosition(0);
     updatePosition();
     emit stateChanged(QMediaPlayer::StoppedState);
     mediaStatusChanged(eos ? QMediaPlayer::EndOfMedia : QMediaPlayer::LoadedMedia);
@@ -296,9 +293,6 @@ bool QGstreamerMediaPlayer::processBusMessage(const QGstreamerMessage &message)
 
                 parseStreamsAndMetadata();
 
-                if (!qFuzzyCompare(m_playbackRate, qreal(1.0)))
-                    playerPipeline.seek(playerPipeline.position(), m_playbackRate);
-
                 emit tracksChanged();
                 mediaStatusChanged(QMediaPlayer::LoadedMedia);
             }
@@ -588,6 +582,7 @@ void QGstreamerMediaPlayer::setMedia(const QUrl &content, QIODevice *stream)
             qCWarning(qLcMediaPlayer) << "Unable to set the pipeline to the paused state.";
     }
 
+    playerPipeline.setPosition(0);
     positionChanged(0);
 }
 
@@ -742,7 +737,7 @@ void QGstreamerMediaPlayer::setActiveTrack(QPlatformMediaPlayer::TrackType type,
     selector.set("active-pad", streams.at(index));
     // seek to force an immediate change of the stream
     if (playerPipeline.state() == GST_STATE_PLAYING)
-        playerPipeline.seek(playerPipeline.position(), m_playbackRate);
+        playerPipeline.flush();
     else
         m_requiresSeekOnPlay = true;
 }
diff --git a/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer_p.h b/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer_p.h
index 9caa432e3..37a51e4ab 100644
--- a/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer_p.h
+++ b/src/multimedia/platform/gstreamer/common/qgstreamermediaplayer_p.h
@@ -135,7 +135,6 @@ private:
     QIODevice *m_stream = nullptr;
 
     bool prerolling = false;
-    double m_playbackRate = 1.;
     bool m_requiresSeekOnPlay = false;
     qint64 m_duration = 0;
     QTimer positionUpdateTimer;