VideoOutput: Introduce flushMode property

Added flushMode property to QML VideoOutput element to define
what should be shown when flush is requested.

Takes affect only for QDeclarativeVideoRendererBackend
and when QSGVideoItemSurface is already started.

Flushing (passing empty video frame to the surface) is usually performed
when EndOfMedia or playback is stopped.
Which caused disappearing the content and blinking if playlist is used.

Using this property now possible to define
what frame (last, first or empty) should be shown when playback is stopped or finished.

By default shows empty frame (clears the video output).

To show a frame it requires to keep QVideoFrame and thus its data.

Task-number: QTBUG-37301
Task-number: QTBUG-49446
Change-Id: I3be5309217b9f543da804e3b616dee9d97fba65f
Reviewed-by: Andy Shaw <andy.shaw@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 15 insertions, 7 deletions

diff --git a/src/qtmultimediaquicktools/qdeclarativevideooutput_render.cpp b/src/qtmultimediaquicktools/qdeclarativevideooutput_render.cpp
index c51aec088..007e52409 100644
--- a/src/qtmultimediaquicktools/qdeclarativevideooutput_render.cpp
+++ b/src/qtmultimediaquicktools/qdeclarativevideooutput_render.cpp
@@ -210,13 +210,13 @@ void QDeclarativeVideoRendererBackend::releaseControl()
 
 QSize QDeclarativeVideoRendererBackend::nativeSize() const
 {
-    return m_surface->surfaceFormat().sizeHint();
+    return m_surfaceFormat.sizeHint();
 }
 
 void QDeclarativeVideoRendererBackend::updateGeometry()
 {
-    const QRectF viewport = videoSurface()->surfaceFormat().viewport();
-    const QSizeF frameSize = videoSurface()->surfaceFormat().frameSize();
+    const QRectF viewport = m_surfaceFormat.viewport();
+    const QSizeF frameSize = m_surfaceFormat.frameSize();
     const QRectF normalizedViewport(viewport.x() / frameSize.width(),
                                     viewport.y() / frameSize.height(),
                                     viewport.width() / frameSize.width(),
@@ -257,13 +257,13 @@ void QDeclarativeVideoRendererBackend::updateGeometry()
         }
     }
 
-    if (videoSurface()->surfaceFormat().scanLineDirection() == QVideoSurfaceFormat::BottomToTop) {
+    if (m_surfaceFormat.scanLineDirection() == QVideoSurfaceFormat::BottomToTop) {
         qreal top = m_sourceTextureRect.top();
         m_sourceTextureRect.setTop(m_sourceTextureRect.bottom());
         m_sourceTextureRect.setBottom(top);
     }
 
-    if (videoSurface()->surfaceFormat().property("mirrored").toBool()) {
+    if (m_surfaceFormat.property("mirrored").toBool()) {
         qreal left = m_sourceTextureRect.left();
         m_sourceTextureRect.setLeft(m_sourceTextureRect.right());
         m_sourceTextureRect.setRight(left);
@@ -294,7 +294,7 @@ QSGNode *QDeclarativeVideoRendererBackend::updatePaintNode(QSGNode *oldNode,
     if (m_frameChanged) {
         // Run the VideoFilter if there is one. This must be done before potentially changing the videonode below.
         if (m_frame.isValid() && !m_filters.isEmpty()) {
-            const QVideoSurfaceFormat surfaceFormat = videoSurface()->surfaceFormat();
+            const QVideoSurfaceFormat surfaceFormat = m_surfaceFormat;
             for (int i = 0; i < m_filters.count(); ++i) {
                 QAbstractVideoFilter *filter = m_filters[i].filter;
                 QVideoFilterRunnable *&runnable = m_filters[i].runnable;
@@ -367,6 +367,12 @@ QSGNode *QDeclarativeVideoRendererBackend::updatePaintNode(QSGNode *oldNode,
         if (isFrameModified)
             flags |= QSGVideoNode::FrameFiltered;
         videoNode->setCurrentFrame(m_frame, flags);
+
+        if ((q->flushMode() == QDeclarativeVideoOutput::FirstFrame && !m_frameOnFlush.isValid())
+            || q->flushMode() == QDeclarativeVideoOutput::LastFrame) {
+            m_frameOnFlush = m_frame;
+        }
+
         //don't keep the frame for more than really necessary
         m_frameChanged = false;
         m_frame = QVideoFrame();
@@ -403,7 +409,7 @@ QOpenGLContext *QDeclarativeVideoRendererBackend::glContext() const
 void QDeclarativeVideoRendererBackend::present(const QVideoFrame &frame)
 {
     m_frameMutex.lock();
-    m_frame = frame;
+    m_frame = frame.isValid() ? frame : m_frameOnFlush;
     m_frameChanged = true;
     m_frameMutex.unlock();
 
@@ -450,10 +456,12 @@ QList<QVideoFrame::PixelFormat> QSGVideoItemSurface::supportedPixelFormats(
 bool QSGVideoItemSurface::start(const QVideoSurfaceFormat &format)
 {
     qCDebug(qLcVideo) << "Video surface format:" << format << "all supported formats:" << supportedPixelFormats(format.handleType());
+    m_backend->m_frameOnFlush = QVideoFrame();
 
     if (!supportedPixelFormats(format.handleType()).contains(format.pixelFormat()))
         return false;
 
+    m_backend->m_surfaceFormat = format;
     return QAbstractVideoSurface::start(format);
 }