Resync_marker length for MPEG4 B-vop

[adkumar]

Resync_marker length for MPEG4 B-vop:
The following is implemented in reference decoder
f_code_max = (f_code_for > f_code_back) ? f_code_for : f_code_back;
if (VopType == B_VOP)
resync_marker_length = 16+f_code_max + (QuarterPel? 1:0);
But standard says
for a B-VOP, the resync_marker is max(15+fcode,17) zeros followed by a one

I could not understand the reason for the mismatch between standard and reference decoder

any clarification regarding this?

Regards,
Kumar