A generator for de-unsynchronizing a byte iterable.

def gen_decode(iterable):
        "A generator for de-unsynchronizing a byte iterable."
        sync = False
        for b in iterable:
            if sync and b & 0xE0:
                warn("Invalid unsynched data", Warning)
            if not (sync and b == 0x00):
                yield b
            sync = (b == 0xFF)