GStreamer: fix assertion failure in QGstreamerMediaCapture

we don't need to sync the state with the parent element, considering
that we're running inside a `modifyPipelineWhileNotRunning` context.

Pick-to: 6.5
Change-Id: I9e57f621c70da80ed5b4e91143183c91fe081493
Reviewed-by: Jøger Hansegård <joger.hansegard@qt.io>
Reviewed-by: Artem Dyomin <artem.dyomin@qt.io>
(cherry picked from commit ccf3c2296c24b82960c9f036c83885964c560638)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit dba66bea72f133760f85283d90497ce5a153ef71)

2 files changed, 1 insertions, 2 deletions

diff --git a/src/plugins/multimedia/gstreamer/common/qgst.cpp b/src/plugins/multimedia/gstreamer/common/qgst.cpp
index 301989833..4aa7c83f9 100644
--- a/src/plugins/multimedia/gstreamer/common/qgst.cpp
+++ b/src/plugins/multimedia/gstreamer/common/qgst.cpp
@@ -832,6 +832,7 @@ bool QGstElement::setStateSync(GstState state, std::chrono::nanoseconds timeout)
 
 bool QGstElement::syncStateWithParent()
 {
+    Q_ASSERT(element());
     return gst_element_sync_state_with_parent(element()) == TRUE;
 }
 
diff --git a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp
index 40ad0bc74..839187a9d 100644
--- a/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp
+++ b/src/plugins/multimedia/gstreamer/mediacapture/qgstreamermediacapture.cpp
@@ -209,7 +209,6 @@ void QGstreamerMediaCapture::linkEncoder(QGstPad audioSink, QGstPad videoSink)
 
             encoderVideoCapsFilter.src().link(videoSink);
             linkTeeToPad(gstVideoTee, encoderVideoCapsFilter.sink());
-            encoderVideoCapsFilter.syncStateWithParent();
             encoderVideoSink = encoderVideoCapsFilter.sink();
         }
 
@@ -225,7 +224,6 @@ void QGstreamerMediaCapture::linkEncoder(QGstPad audioSink, QGstPad videoSink)
 
             encoderAudioCapsFilter.src().link(audioSink);
             linkTeeToPad(gstAudioTee, encoderAudioCapsFilter.sink());
-            encoderVideoCapsFilter.syncStateWithParent();
             encoderAudioSink = encoderAudioCapsFilter.sink();
         }
     });