I've added a very crude pseudo AFC to float_to_bits. It uses an averaging
filter on the input values, and compensates for any fixed offset it finds
in the input data (if all bit combinations are equally likely to appear in
the input stream, then a long-term average should be 0).
This helps a bit when decoding a mistuned signal (due to receiver
frequency drift etc). From a quick test yesterday normally the receiver
works when the signal is mistuned from -1.6 to 1.3kHz, with the -a option
the receiver works when the signal is mistuned from -2.8 to 2kHz.
Diff included, or source here: