@raoul Having the Segmentation fault error on OpenLP start here on Mint 19.3 64 bit too. Below is a back trace from gdb if it helps:
(gdb) bt
#0 __memcpy_ssse3 () at ../sysdeps/x86_64/multiarch/memcpy-ssse3.S:309
#1 0x00007fff636a7706 in ?? ()
from /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
#2 0x00007fffa9e72229 in ?? ()
from /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstvaapi.so
#3 0x00007fffa9e3e0c4 in ?? ()
from /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstvaapi.so
#4 0x00007fffa9e3f9df in ?? ()
from /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstvaapi.so
#5 0x00007fffa9e496e8 in ?? ()
from /usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstvaapi.so
#6 0x00007fffe45df812 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgstbase-1.0.so.0
#7 0x00007fffe42d4d5e in gst_element_change_state ()
from /usr/lib/x86_64-linux-gnu/libgstreamer-1.0.so.0
#8 0x00007fffe42d5499 in ?? ()
from /usr/lib/x86_64-linux-gnu/libgstreamer-1.0.so.0
#9 0x00007fffaad31285 in QGstreamerVideoOverlay::findBestVideoSink() const ()
from /usr/lib/x86_64-linux-gnu/libqgsttools_p.so.1
#10 0x00007fffaad314e0 in QGstreamerVideoOverlay::QGstreamerVideoOverlay(QObject*, QByteArray const&) () from /usr/lib/x86_64-linux-gnu/libqgsttools_p.so.1
#11 0x00007fffaad308a5 in QGstreamerVideoWindow::QGstreamerVideoWindow(QObject*, QByteArray const&) () from /usr/lib/x86_64-linux-gnu/libqgsttools_p.so.1
---Type <return> to continue, or q <return> to quit---
#12 0x00007fffaaf49c73 in ?? ()
from /usr/lib/x86_64-linux-gnu/qt5/plugins/mediaservice/libgstmediaplayer.so
#13 0x00007fffaaf58041 in ?? ()
from /usr/lib/x86_64-linux-gnu/qt5/plugins/mediaservice/libgstmediaplayer.so
#14 0x00007fffeb9eac97 in ?? ()
from /usr/lib/x86_64-linux-gnu/libQt5Multimedia.so.5
#15 0x00007fffeba33bf9 in QMediaPlayer::QMediaPlayer(QObject*, QFlags<QMediaPlayer::Flag>) () from /usr/lib/x86_64-linux-gnu/libQt5Multimedia.so.5
#16 0x00007fffebcf6499 in ?? ()
from /usr/lib/python3/dist-packages/PyQt5/QtMultimedia.cpython-36m-x86_64-linux-gnu.so
#17 0x00007fffebcf6581 in ?? ()
from /usr/lib/python3/dist-packages/PyQt5/QtMultimedia.cpython-36m-x86_64-linux-gnu.so
#18 0x00007ffff1ebc654 in ?? ()
from /usr/lib/python3/dist-packages/sip.cpython-36m-x86_64-linux-gnu.so
#19 0x0000000000551391 in ?? ()
#20 0x00000000005a9d2c in _PyObject_FastCallKeywords ()
#21 0x000000000050a533 in ?? ()
#22 0x000000000050bf44 in _PyEval_EvalFrameDefault ()
#23 0x0000000000507cd4 in ?? ()
#24 0x0000000000508fb2 in _PyFunction_FastCallDict ()
#25 0x0000000000595221 in ?? ()
---Type <return> to continue, or q <return> to quit---
#26 0x0000000000549b3f in ?? ()
#27 0x0000000000551391 in ?? ()
#28 0x00000000005a9d2c in _PyObject_FastCallKeywords ()
#29 0x000000000050a533 in ?? ()
#30 0x000000000050bf44 in _PyEval_EvalFrameDefault ()
#31 0x0000000000507cd4 in ?? ()
#32 0x0000000000508fb2 in _PyFunction_FastCallDict ()
#33 0x0000000000595221 in ?? ()
#34 0x00000000005a058e in PyObject_Call ()
#35 0x000000000050d4ff in _PyEval_EvalFrameDefault ()
#36 0x0000000000507cd4 in ?? ()
#37 0x0000000000509a00 in ?? ()
#38 0x000000000050a3fd in ?? ()
#39 0x000000000050bf44 in _PyEval_EvalFrameDefault ()
#40 0x00000000005096c8 in ?? ()
#41 0x000000000050a3fd in ?? ()
#42 0x000000000050bf44 in _PyEval_EvalFrameDefault ()
#43 0x0000000000506044 in ?? ()
#44 0x000000000050a3fd in ?? ()
#45 0x000000000050bf44 in _PyEval_EvalFrameDefault ()
#46 0x0000000000507cd4 in ?? ()
#47 0x000000000050ae13 in PyEval_EvalCode ()
#48 0x0000000000635262 in ?? ()
---Type <return> to continue, or q <return> to quit---
#49 0x0000000000635317 in PyRun_FileExFlags ()
#50 0x0000000000638acf in PyRun_SimpleFileExFlags ()
#51 0x0000000000639671 in Py_Main ()
#52 0x00000000004b0e40 in main ()