Reading x264 bitstream using JM Reference

I have encoded a video to a raw 264 bitstream using x264. JM decoder correctly decode the video. However, when I try to extract the modes and motion vectors of the macr开发者_开发问答oblock by printing out the macroblock info, they print out the wrong values. Have anyone experience these before ?

I modified JM decoder to calculate and print the correct MVs and modes. I verified the result with videos encoded by JM itself. However, it does not work for .264 bitstream encoded by x264. But still, the video is decoded correctly.