Nice find! It looks like it uses https://github.com/deepmedia/Transcoder. I might be able to switch to this directly from our current compressor.
Sounds great! I'm also thinking about building something more serious—maybe an all-in-one toolkit app with built-in micro-apps and Nostr DVMs for more complex tasks. Side note: I'm using your Amethyst repo to learn Kotlin, and thanks again for putting so much of your energy into building this amazing app.