[FFmpeg-user] how to define the GOP frame types and GOD display order

[webb.jordan.zh]

Hello

I want to convert dv-avi format video to mp4 format video with h264 encoding and the the GOP display order and GOP frame types must be:
GOP Display Order: 3 2 0 1 7 6 4 5 11 10 8 9 15 14 12 13 19 18 16 17 23 22 20 21 27 26 24 25
GOP Frame Types: IBBBPBBBPBBBPBBBPBBBPBBBPBBB

I using command line for this:
"..\ffmpeg.exe" -i "D:\Video\03000.avi"  -vcodec libx264 -pix_fmt yuv420p -r 59.94 -aspect 16:9 -s 1280x720 -b:v 8000k -level 4 -refs 4 -preset faster -x264opts keyint=28:bframes=3:b_pyramid=none:open_gop=1 -mbd 2 -an -y "D:\xxTest\DV-MP4HD.mp4"

But the GOP Frame Types of the converted video is : IBPBPBPBPBPBPBPBPBPBPBPBPBPB

What wrong of the command line? I need any helps from anyones, Thank you very much!