ROSI-LTS only: Main ROSI bundles FFmpeg; this guide applies to ROSI-LTS, which requires FFmpeg in your PATH.
Use a current FFmpeg build for your operating system. ROSI-LTS needs an executable named ffmpeg on PATH, or a custom path set in its settings.
Windows
Quickest option:
winget install ffmpegOr with Chocolatey: choco install ffmpeg-full
Verify: ffmpeg -version
macOS
brew install ffmpegVerify: ffmpeg -version
Linux
Debian / Ubuntu
sudo apt install ffmpeg -yFedora
sudo dnf install ffmpeg -yArch
sudo pacman -S ffmpegVerify on any distro: ffmpeg -version