Miller encoding

Hi there, i research some rf stuff and did it so far with a radio
scanner and a soundcard, but lately we have aquired now a fine
hardware with the right boards. So i wanted to start to port this to
gnu radio.
It seems to be a miller encoding on top of the FM/FSK signal. I
didn’t find so far an implementation in code in the internet. I
hacked something together but am unsure about the correctness.

Does someone here have experiences in miller decoding.