To support formats like MIL-STD-2045-47001D (which is public), DFDL needs enhancement with a property to allow specification of bit order. That is, whether the bits of a byte are numbered most-significant-bit-first, or least-significant-bit-first.

A new DFDL property will need to be created to specify this.

See http://redmine.ogf.org/boards/15/topics/43 which is the DFDL public comment forum thread for this topic.

Small example:

Consider a single byte with 3 bit fields within it, a 3-bit-long field containing value 3, or binary 011, another 3-bit-long field containing value 4 or binary 100, and a 2-bit-long field containing value 1 or binary 01.

DFDL today interprets this most-significant bit first. So the binary representations are concatenated as 01110001 which is byte 0x71.

A format like MIL-STD-2045-47001D instead requires that this be interpreted with least significant bit first so the same 3 fields turn into this number: 01100011 which is 0x63.