Install FFmpeg
FFmpeg is used by Editframe to encode your composition into a video file.
Mac
brew install ffmpeg
If you don't have Homebrew, install it first.
Windows
winget install Gyan.FFmpeg
Or download a build from ffmpeg.org and add it to your PATH.
Linux
sudo apt install ffmpeg
Verify
ffmpeg -version
You should see version info starting with ffmpeg version ....