The FDI format
(google "Disk2FDI") is open and complete, and there's a
few emulators supporting it (WinUAE, others that are also non-Amiga).
Doesn't require a catweasel either.
Wow, looks like it can handle both raw bitstreams, and decoded bitstreams too,
not to mention fully decoded sectors...
It doesn't appear they've ever has do deal with anything but soft-sectored
formats
though.