Changes to QMediaPlayer GStreamer backend to allow setPosition before pause

Do not display prerolled frames in stopped state.
Instead store prerolled frame and display it only after switching to
pause or playback state.
Added new unit test with a sample video file to check this functionality.

Change-Id: I3fd159a199b65ca10fdf9843af5675c5ae9dad05
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>

tests/auto/integration/qmediaplayerbackend/tst_qmediaplayerbackend.cpp

@@ -41,6 +41,7 @@
 
 #include <QtTest/QtTest>
 #include <QDebug>
+#include <qabstractvideosurface.h>
 #include "qmediaservice.h"
 #include "qmediaplayer.h"
 
@@ -76,12 +77,38 @@ private slots:
     void volumeAndMuted();
     void volumeAcrossFiles_data();
     void volumeAcrossFiles();
+    void seekPauseSeek();
 
 private:
     //one second local wav file
     QMediaContent localWavFile;
 };
 
+/*
+    This is a simple video surface which records all presented frames.
+*/
+
+class TestVideoSurface : public QAbstractVideoSurface
+{
+    Q_OBJECT
+public:
+    explicit TestVideoSurface() { }
+
+    //video surface
+    QList<QVideoFrame::PixelFormat> supportedPixelFormats(
+            QAbstractVideoBuffer::HandleType handleType = QAbstractVideoBuffer::NoHandle) const;
+
+    bool start(const QVideoSurfaceFormat &format);
+    void stop();
+    bool present(const QVideoFrame &frame);
+
+    QList<QVideoFrame>& frameList() { return m_frameList; }
+
+private:
+    QList<QVideoFrame> m_frameList;
+};
+
+
 void tst_QMediaPlayerBackend::init()
 {
 }
@@ -409,6 +436,104 @@ void tst_QMediaPlayerBackend::volumeAcrossFiles()
     QCOMPARE(player.isMuted(), muted);
 }
 
+void tst_QMediaPlayerBackend::seekPauseSeek()
+{
+    QMediaPlayer player;
+
+    QSignalSpy positionSpy(&player, SIGNAL(positionChanged(qint64)));
+
+    TestVideoSurface *surface = new TestVideoSurface;
+    player.setVideoOutput(surface);
+
+    QFileInfo videoFile(QLatin1String(TESTDATA_DIR "testdata/colors.mp4"));
+    QVERIFY(videoFile.exists());
+
+    player.setMedia(QUrl::fromLocalFile(videoFile.absoluteFilePath()));
+    QCOMPARE(player.state(), QMediaPlayer::StoppedState);
+    QVERIFY(surface->frameList().isEmpty()); // frame must not appear until we call pause() or play()
+
+    positionSpy.clear();
+    player.setPosition((qint64)7000);
+    QTRY_VERIFY(!positionSpy.isEmpty() && qAbs(player.position() - (qint64)7000) < (qint64)500);
+    QCOMPARE(player.state(), QMediaPlayer::StoppedState);
+    QTest::qWait(250); // wait a bit to ensure the frame is not rendered
+    QVERIFY(surface->frameList().isEmpty()); // still no frame, we must call pause() or play() to see a frame
+
+    player.pause();
+    QTRY_COMPARE(player.state(), QMediaPlayer::PausedState); // it might take some time for the operation to be completed
+    QTRY_COMPARE(surface->frameList().size(), 1); // we must see a frame at position 7000 here
+
+    {
+        QVideoFrame frame = surface->frameList().back();
+        QVERIFY(qAbs(frame.startTime() - (qint64)7000) < (qint64)500);
+        QCOMPARE(frame.width(), 160);
+        QCOMPARE(frame.height(), 120);
+
+        // create QImage for QVideoFrame to verify RGB pixel colors
+        QVERIFY(frame.map(QAbstractVideoBuffer::ReadOnly));
+        QImage image(frame.bits(), frame.width(), frame.height(), QVideoFrame::imageFormatFromPixelFormat(frame.pixelFormat()));
+        QVERIFY(!image.isNull());
+        QVERIFY(qRed(image.pixel(0, 0)) >= 240); // conversion from YUV => RGB, that's why it's not 255
+        QCOMPARE(qGreen(image.pixel(0, 0)), 0);
+        QCOMPARE(qBlue(image.pixel(0, 0)), 0);
+        frame.unmap();
+    }
+
+    positionSpy.clear();
+    player.setPosition((qint64)12000);
+    QTRY_VERIFY(!positionSpy.isEmpty() && qAbs(player.position() - (qint64)12000) < (qint64)500);
+    QCOMPARE(player.state(), QMediaPlayer::PausedState);
+    QCOMPARE(surface->frameList().size(), 2);
+
+    {
+        QVideoFrame frame = surface->frameList().back();
+        QVERIFY(qAbs(frame.startTime() - (qint64)12000) < (qint64)500);
+        QCOMPARE(frame.width(), 160);
+        QCOMPARE(frame.height(), 120);
+
+        QVERIFY(frame.map(QAbstractVideoBuffer::ReadOnly));
+        QImage image(frame.bits(), frame.width(), frame.height(), QVideoFrame::imageFormatFromPixelFormat(frame.pixelFormat()));
+        QVERIFY(!image.isNull());
+        QCOMPARE(qRed(image.pixel(0, 0)), 0);
+        QVERIFY(qGreen(image.pixel(0, 0)) >= 240);
+        QCOMPARE(qBlue(image.pixel(0, 0)), 0);
+        frame.unmap();
+    }
+}
+
+QList<QVideoFrame::PixelFormat> TestVideoSurface::supportedPixelFormats(
+        QAbstractVideoBuffer::HandleType handleType) const
+{
+    if (handleType == QAbstractVideoBuffer::NoHandle) {
+        return QList<QVideoFrame::PixelFormat>()
+                << QVideoFrame::Format_RGB32
+                << QVideoFrame::Format_ARGB32
+                << QVideoFrame::Format_ARGB32_Premultiplied
+                << QVideoFrame::Format_RGB565
+                << QVideoFrame::Format_RGB555;
+    } else {
+        return QList<QVideoFrame::PixelFormat>();
+    }
+}
+
+bool TestVideoSurface::start(const QVideoSurfaceFormat &format)
+{
+    if (!isFormatSupported(format)) return false;
+
+    return QAbstractVideoSurface::start(format);
+}
+
+void TestVideoSurface::stop()
+{
+    QAbstractVideoSurface::stop();
+}
+
+bool TestVideoSurface::present(const QVideoFrame &frame)
+{
+    m_frameList.push_back(frame);
+    return true;
+}
+
 
 QTEST_MAIN(tst_QMediaPlayerBackend)
 #include "tst_qmediaplayerbackend.moc"