This example shows how one could implement a video player in Kotlin. Almost any video file supported by ffmpeg could be played with it. ffmpeg and SDL2 is needed for that to work, i.e.
port install ffmpeg-devel brew install ffmpeg sdl2 apt install libavcodec-dev libavformat-dev libavutil-dev libswscale-dev libswresample-dev apt install libsdl2-dev pacman -S mingw-w64-x86_64-SDL2 mingw-w64-x86_64-ffmpeg
To build use ../gradlew assemble.
To run use ./build/bin/videoPlayer/main/release/executable/videoplayer.kexe <file>.mp4.