GStreamer error in Qt5

Question

When I try to launch my videowidget application it gives me the error:

(videowidget:9305): GLib-GObject-WARNING **: cannot register existing type 'GstObject'

(videowidget:9305): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed

(videowidget:9305): GLib-GObject-CRITICAL **: g_type_register_static: assertion 'parent_type > 0' failed

(videowidget:9305): GLib-CRITICAL **: g_once_init_leave: assertion 'result != 0' failed

(videowidget:9305): GStreamer-CRITICAL **: gst_element_class_set_details_simple: assertion 'GST_IS_ELEMENT_CLASS (klass)' failed

(videowidget:9305): GStreamer-WARNING **: static caps 0xade3824c string is NULL

(videowidget:9305): GStreamer-CRITICAL **: gst_mini_object_unref: assertion 'mini_object != NULL' failed

(videowidget:9305): GStreamer-WARNING **: static caps 0xade3828c string is NULL

(videowidget:9305): GStreamer-CRITICAL **: gst_mini_object_unref: assertion 'mini_object != NULL' failed

(videowidget:9305): GStreamer-WARNING **: static caps 0xade3824c string is NULL

(videowidget:9305): GStreamer-CRITICAL **: gst_mini_object_unref: assertion 'mini_object != NULL' failed

I have two GStreamer versions installed on my target machine 0.10 and 1.0 which runs on Jessie 8.2.

I figured out that when I uninstall 1.0, 0.10 version requires an .so file from gstreamer1.0.

VideoWidget example from Qt example folder works fine, but the simple example from doc.qt.io/qt-5/videooverview.html won't work.

Answer 1

1.0 and 0.10 are parallel installable and I doubt one is trying to use a file from the other.

Those issues usually happen when the application was linked against both versions. While you can have both at your system, applications should link only against one of them.

Answer 2

when you construct an object ,it's parent should be Q_NULL_POINTER.

QFileDialog *pDlg = new QFileDialog();

instead of

QFileDialog *pDlg = new QFileDialog(this);