On Tue, Jan 23, 2007 at 09:10:43AM +0100, Clemens Ladisch wrote:
nut.txt says: | back_ptr_div16 (v) | back_ptr = back_ptr_div16 * 16 + 15 | back_ptr must point to a position within 16 bytes of a syncpoint | startcode. [...]
Does "within 16 bytes" mean before or after the syncpoint startcode? This description also doesn't mention that this value is relative.
I think the semantics were intended to be similar to syncpoint_pos_div16 in the index, so probably that description can be copied and adapted:
| syncpoint_pos_div16 (v) | offset from beginning of file to up to 15 bytes before the syncpoint | referred to in this index entry. Relative to position of last | syncpoint.
except back_ptr is relative to the current position, not absolute/from beginning of file. and within 16 bytes is supposed to mean that the startcode begins on the pointed-to byte or one of the 15 following bytes. i suppose this could use some clarification in the spec. :) rich