[Mp4-tech] gaps_in_frame_num_value_allowed_flag...???

[Deepak Singh]

Dear Experts,
I have query related to gaps_in_frame_num_value_allowed_flag and frame_num.
As per my understanding of standard when
gaps_in_frame_num_value_allowed_flag is 0 then frame_num will be in
non decreasing order till next IDR frame and the value of frame_num
increase with plus 1 with respect to previous reference frame.
Let me put an example for it.
Lets assume B- frame is not used for reference.
In h.264 coded bitstream the frames are : (frame_num as per my
understanding it will be)
Note: gaps_in_frame_num_value_allowed_flag = 0
Coded Frame  :  IDR -> P-> P-> B->B-> P-> P->IDR->....
Frame_num    :  0         1    2     3    3    4    5     0
My question is for the same sequence if
gaps_in_frame_num_value_allowed_flag = 1 and non- existing frame
exists as
Note: gaps_in_frame_num_value_allowed_flag = 1
Coded Frame : IDR -> P-> non-exist frame->P-> B->B->non-exist
frame->non-exist frame-> P-> P->IDR->....
Frame_num   :  0       1                ?               ?     ?    ?
             ?                ?               ?     ?     0
How the frame_num value will behave for the above situation???
-- 
Regards,
Deepak Singh