Mpph264enc/265enc Unable to limit bitrate

I am using mpph264enc to encode h.264 video. I tried using bps, bsp_max, rc-mode to limit output bitrate, but even I set bps to 100000(100kbps), the video output still getting 4000kbps in vbr mode or 30000+kbps in cbr mode.

How can I get low bitrate video?
Thanks!

gst-launch-1.0 v4l2src device=/dev/video0 ! ‘video/x-raw,width=1920,height=1080,framerate=60/1’ ! mpph264enc bps=100000 rc-mode=cbr ! h264parse ! matroskamux name=mux ! filesink location=test.mkv