This piece of code will send your clipboard image to ffmpeg. The desired output is left as an exercise for the user!
cargo build --release
The executable will be located at target/release/ffclip
Once an image is in your clipboard (and FFmpeg exists in your PATH env):
./ffclip .webp
./ffclip image.png
./ffclip -qscale:v 2 capybara.jpg
The app is cross-platform thanks to arboard.