[M4IF Technotes] Is OBMC implementation different from Momusys and 14496-2??

[CC_Ju mtk.com.tw]

Dear all:
    I don't know if I misunderstand the OBMC implementation in Momusys
software. It seems to use only up, left, right, and current macroblock's
motion vector to do OBMC operation. The motion vector in bottom macroblock
seems don't used in OBMC operation. This differs from 14496-2
specification. Anybody can help?
Thanks in advance.
---
Chi-Cheng