gdb call stack:
(gdb) bt
#0 QAbstractSlider::isSliderDown() const (this=0x0) at /usr/src/debug/qtbase/5.15.7+gitAUTOINC+358aebba72-r0/git/src/widgets/widgets/qabstractslider.cpp:482
#1 0x0000005555560b90 in ()
#2 0x0000007ff6b14a34 in QtPrivate::QSlotObjectBase::call(QObject*, void**) (a=0x7fffffe378, r=<optimized out>, this=0x55556d9890)
at ../../include/QtCore/../../../git/src/corelib/kernel/qobjectdefs_impl.h:398
#3 doActivate<false>(QObject*, int, void**) (sender=0x55555bd7f0, signal_index=14, argv=0x7fffffe378)
at /usr/src/debug/qtbase/5.15.7+gitAUTOINC+358aebba72-r0/git/src/corelib/kernel/qobject.cpp:3919
#4 0x0000007ff6b0d664 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**)
(sender=<optimized out>, m=<optimized out>, local_signal_index=local_signal_index@entry=5, argv=argv@entry=0x7fffffe378)
at /usr/src/debug/qtbase/5.15.7+gitAUTOINC+358aebba72-r0/git/src/corelib/kernel/qobject.cpp:3979
#5 0x0000007ff7ef1134 in QMediaPlayer::positionChanged(long long) (this=<optimized out>, _t1=<optimized out>) at .moc/moc_qmediaplayer.cpp:751
#6 0x0000007ff6b14a34 in QtPrivate::QSlotObjectBase::call(QObject*, void**) (a=0x7fffffe4a8, r=<optimized out>, this=0x55556d3b30)
at ../../include/QtCore/../../../git/src/corelib/kernel/qobjectdefs_impl.h:398
#7 doActivate<false>(QObject*, int, void**) (sender=0x55556bf130, signal_index=5, argv=0x7fffffe4a8)
at /usr/src/debug/qtbase/5.15.7+gitAUTOINC+358aebba72-r0/git/src/corelib/kernel/qobject.cpp:3919
#8 0x0000007ff6b0d664 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**)
(sender=sender@entry=0x55556bf130, m=<optimized out>, local_signal_index=local_signal_index@entry=2, argv=argv@entry=0x7fffffe4a8)
at /usr/src/debug/qtbase/5.15.7+gitAUTOINC+358aebba72-r0/git/src/corelib/kernel/qobject.cpp:3979
#9 0x0000007ff7ee3e64 in QMediaPlayerControl::positionChanged(long long) (this=this@entry=0x55556bf130, _t1=<optimized out>) at .moc/moc_qmediaplayercontrol.cpp:344
#10 0x0000007ff501611c in QGstreamerPlayerControl::setMedia(QMediaContent const&, QIODevice*) (this=0x55556bf130, content=..., stream=0x0)
at /usr/src/debug/qtmultimedia/5.15.7+gitAUTOINC+eeb34aae03-r0/git/src/gsttools/qgstreamerplayercontrol.cpp:403
#11 0x0000007ff7ef1bb4 in QMediaPlayerPrivate::setMedia(QMediaContent const&, QIODevice*) (this=this@entry=0x55555bd810, media=..., stream=stream@entry=0x0)
at /usr/src/debug/qtmultimedia/5.15.7+gitAUTOINC+eeb34aae03-r0/git/src/multimedia/playback/qmediaplayer.cpp:412
#12 0x0000007ff7ef4b90 in QMediaPlayer::setMedia(QMediaContent const&, QIODevice*) (this=0x55555bd7f0, media=..., stream=0x0)
at /usr/src/debug/qtmultimedia/5.15.7+gitAUTOINC+eeb34aae03-r0/git/src/multimedia/playback/qmediaplayer.cpp:1094
#13 0x0000005555561db4 in ()
#14 0x000000555555e4c4 in main ()