FFmpeg is mostly LGPL and has very clear and helpful instructions about how to incorporate and distribute it in compliance.

It does not require that you do that. It only requires you to open source any modifications you've made to ffmpeg.

it is slightly more nuanced, if you do static linking it is considered derivative work and does requires you to open it. Since the app is based on ffmpeg which is GPL(core is LGPL) i am curious to know how it is getting used.

i didn't bundle the ffmpeg in the app. It uses homebrew to install ffmpeg on the user's device. this is the acceptable way since ffmpeg confirms it on twitter/X.

https://x.com/FFmpeg/status/1766649563891339510

This tweet also explicitly says "But still would be nice to have some credit.".

Why isn't FFmpeg mentioned on your app's website?

The same goes for ImageMagick by the way.

there is a dedicated page for credits: https://pimosa.app/credits

Static linking of LGPL content (thus making it derivative work) only requires that it must allow "modification of the work for the customer's own use and reverse engineering for debugging such modifications".

Making your own code public is not the only way to achieve this.

You can also make available to customer object files and build instructions to recreate your software with the (modified) statically linked LGPL content. (if it's LGPL > 2.1 you have extra requirements: you need to provide all toolchains/dependencies and it must be actually possible to install a modified version on the hardware)

Granted, this is not commonly used but I've used this on some projects where dynamic linking was not available/desired by client.

it uses homebrew to install the FFmpeg on the user's device. the app doesn't bundle any libs to comply with their license limitations.

O_o, well that was a short lived app.

FFmpeg is LGPL, not GPL. This means that you can link it in non open source apps and only have to open source modifications to FFmpeg itself.

It doesn't if you use it as a bundled binary.

https://opensource.stackexchange.com/questions/4008/can-i-us...

https://opensource.stackexchange.com/questions/5188/software...