[Mp4-tech] About level_prefix of cavlc!

[JelyZhu innosis.com.cn]

Hi experts,
I have a question about the range of level_prefix of cavlc.
In Table9-6 of the latest H.264 standard, level_prefix can be greater than
15. But I have seen a paper in which level_prefix cannot be greater than
15. I don't know what on earth the range of level_prefix is, [0,15] or any
else?
Thanks in advance.
Best Regards,
Jely