This is only for Raspberry Pie!

You’ll need first a proper videopack for a bunch of system.
These can be found here

Thanks to the author for these gems

Create a directory with mkdir /userdata/videoloadingscreens and then copy the whole content of the google drive to this directory

Then we need some scripting.

Create directory scripts with mkdir /userdata/system/scripts
Paste text from down to /userdata/system/scripts/videolaunch.sh
Make script executable with chmod +x /userdata/system/scripts/videolaunch.sh

#!/bin/bash
do_videostart ()
{
    video="$1"
    # Launch the video
    omx_fnt="--font=/usr/share/fonts/dejavu/DejaVuSans-BoldOblique.ttf"
    omx_opt="--no-keys --layer=10000 --aspect-mode=fill"
    omx_srt="--no-ghost-box --lines=1 --align=left $omx_fnt --font-size=20 --subtitles=/usr/share/batocera/splash/splash.srt"

    # Disable sound
    omx_nosound="-n -1"
    # -911 = Volume set to 35% (On omxplayer)
    # 1/(10^(911/2000)) = 0.35034828830157

    /usr/bin/omxplayer -o both --vol -2500 $omx_opt $omx_srt $omx_nosound $video &
    PID=$!
}


videopath="/userdata/videoloadingscreens"

if [[ "$1" == "gameStart" && -n "$2" ]]; then
    video="${videopath}/$2.mp4"
    # Filecheck
    [[ -f "$video" ]] || exit 1
else
    exit 1
fi

do_videostart "$video"
#wait $PID
exit 0