If someone looks for a smallish project to get started with GStreamer in Rust, a FLAC decoder around claxon or an Y4M encoder/decoder around y4m seem like good starter tasks.
See
https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/issues/71
https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs/issues/61
Feel free to ask for more details / help!