MP4 file is not played on the new Raspberry Pi 4 Platform using qmlvideo example

Hello,
I am working towards porting applications and libraries to OpenEmbedded/Yocto. On Raspberry Pi 3, with the Qt example "qmlvideo" (located at /usr/share/examples), I am able to play .mp4 videos. However, when an image is created for Raspberry Pi 4, same video is not played. We are discussing the issue at https://github.com/agherzan/meta-raspberrypi/issues/481

We are using "-platform eglfs" (OpenGL) when launching "qmlvideo". We're not interested in X11 or Wayland solutions. It has been discussed that eglfssink is no more accepted in Raspberry Pi 4, it uses kmssink; but it is not yet well established.

We were able to successfully play a video using the following command:

gst-launch-1.0 -e -vvv filesrc location="/run/media/sda1/mymovie.mp4" ! qtdemux ! h264parse ! avdec_h264 ! kmssink

However, I am not certain how can I modify qtmultimedia (QML-VideoOutput) so that it uses these specific pipes. Is there an easier way without modifying the source code?

I apologize if this question is not well suited here, but I felt like we could use some knowledge of people from Qt in this regard. We hope our fix will benefit all the community who uses Qt in Raspberry Pi 4 on Yocto Linux.

Thanks in advance for your help.
Kind regards.