Solution I found on another topic :
Get non-free repositories
sudo dnf install [https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm](https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm) -E %fedora).noarch.rpm
Switch free ffmpeg for non-free
sudo dnf swap ffmpeg-free ffmpeg --allowerasing