I made a folder with that you can easy create an custom wallpaper and a text how to is also in the folder.
just download it and safe it anywhere on your pc

Open the ffmpe folder and then the bin there you see the how to
i used example paths just change it with your path

https://drive.google.com/drive/folders/1ek0slgajJJaojIpKaRK1kQ15Swu_Fo6x?usp=sharing