You end up guessing bitrates, tweaking CRF values and running FFmpeg repeatedly until the output finally fits.

I wanted to make that process simpler. so I built fp, a CLI that searches for a suitable compression setting to fit a video under a maximum size.

fp compress video.mp4 --size 25mb

Specify the size limit and fp handles the trial and error.

How it works

Built with Rust and powered by FFmpeg, fp:

• Uses ffprobe to inspect video metadata.

• Tries different CRF values and measures actual output sizes.

• Searches within a bounded number of attempts.

• Validates the output against the requested size limit.

• Supports dry runs, custom output paths, and verbose mode.

A real example

I tested it on a 99.8 MB, 1080p video with a target of 25 MB.

The final output was 76.2% smaller than the original and stayed under the requested limit.

No Rust installation? No problem.

Besides installing it through Cargo, fp also provides prebuilt binaries for supported platforms through GitHub Releases. You can download the appropriate binary, extract it and run it without building the project from source.

• Cargo: cargo install ffrp

• Prebuilt binaries: Download from GitHub Releases

You'll still need FFmpeg and ffprobe installed and available on your PATH.

What's next?

There's still room to improve the CLI and explore features like splitting videos into smaller chunks without re encoding.

The project is open source and I would love feedback, suggestions and contributions.

GitHub: https://github.com/SATVIKsynopsis/fp

If you try it, let me know how it goes!