Gstreamer: Set surface from renderer before creating pipeline

When multiple pipelines are created, and one of these gets recreated,
it picks up the last set surface.

This is incorrect, as it needs a surface belonging to the current renderer.

This patch sets the surface before creating pipelines, retrieving it from the current renderer.

Task-number: QTBUG-73557
Change-Id: I0811f7262a0eca57e01361a55515351127520064
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Andy Shaw <andy.shaw@qt.io>

src/gsttools/qgstreamerplayersession.cpp

@@ -47,7 +47,7 @@
 #include <private/gstvideoconnector_p.h>
 #endif
 #include <private/qgstutils_p.h>
-#include <private/qgstutils_p.h>
+#include <private/qvideosurfacegstsink_p.h>
 
 #include <gst/gstvalue.h>
 #include <gst/base/gstbasesrc.h>
@@ -60,6 +60,7 @@
 #include <QtCore/qdebug.h>
 #include <QtCore/qdir.h>
 #include <QtCore/qstandardpaths.h>
+#include <qvideorenderercontrol.h>
 
 //#define DEBUG_PLAYBIN
 //#define DEBUG_VO_BIN_DUMP
@@ -338,6 +339,11 @@ void QGstreamerPlayerSession::loadFromUri(const QNetworkRequest &request)
 #endif
 
     if (m_request.url().scheme() == QLatin1String("gst-pipeline")) {
+        // Set current surface to video sink before creating a pipeline.
+        auto renderer = qobject_cast<QVideoRendererControl*>(m_videoOutput);
+        if (renderer)
+            QVideoSurfaceGstSink::setSurface(renderer->surface());
+
         QString url = m_request.url().toString(QUrl::RemoveScheme);
         QString pipeline = QUrl::fromPercentEncoding(url.toLatin1().constData());
         GError *err = nullptr;

src/gsttools/qgstreamervideorenderer.cpp

@@ -113,7 +113,6 @@ void QGstreamerVideoRenderer::setSurface(QAbstractVideoSurface *surface)
         if (m_surface) {
             connect(m_surface.data(), SIGNAL(supportedFormatsChanged()),
                     this, SLOT(handleFormatChange()));
-            QVideoSurfaceGstSink::setSurface(m_surface);
         }
 
         if (wasReady != isReady())