The current moq-pub implementation only requires valid fMP4 (a la CMAF) to be provided over stdin. I haven't tested, but I imagine you can do the same with gstreamer.

Separately, I've been working on a wrapper library for moq-rs that I've been calling 'libmoq'. The intent there is to provide a C FFI that non-Rust code can link against. The first integration target for libmoq is ffmpeg. (I have a few bugs to work out before I clean up and shout about that code, but it does mostly work already.)

I gave a presentation about some of this work last week at Demuxed, but the VoDs probably won't be available on YouTube until Decemberish.

Also, I understand the gstreamer project has better support for Rust so I'll be looking at that soon, too.