[Mp4-tech] [Video][H.264]Regarding reference picture marking

[Smitha Joseph]

Hi,
I had a doubt regarding the initialisation process for reference
picture lists for B slices in frames (8.2.4.2.3). The process
specifies that if reference list 1 has more than one entry and
reference list 0 and reference list 1 are identical, the first two
entries should be switched. Since the lists are identical why should
there be a switching? Could you please explain the reason behind this?
Thanks,
Smitha Joseph