The param of nv_omx_h264 "quality-level" is useless. Is it a bug?

Here are my command lines :
gst-launch-0.10 filesrc location=fire_420_1920x1080_p300.yuv ! videoparse width=1920 height=1080 format=1 framerate=30/1 ! nv_omx_h264enc quality-level=0 ! qtmux ! filesink location=fire0.mp4 -e

gst-launch-0.10 filesrc location=fire_420_1920x1080_p300.yuv ! videoparse width=1920 height=1080 format=1 framerate=30/1 ! nv_omx_h264enc quality-level=1 ! qtmux ! filesink location=fire1.mp4 -e

gst-launch-0.10 filesrc location=fire_420_1920x1080_p300.yuv ! videoparse width=1920 height=1080 format=1 framerate=30/1 ! nv_omx_h264enc quality-level=2 ! qtmux ! filesink location=fire2.mp4 -e

It seems all these outputs have no difference. That means the param “quality-level” does not work.
Is it a bug? Or did I miss something?

Hello
I also have this problem.
I output test pattern into test.mp4 and command as follow

gst-launch-0.10 videotestsrc num-buffers=200 ! 'video/x-raw-yuv, width=(int)1280, height=(int)720, format=(fourcc)I420' ! nv_omx_h264enc quality-level=2 ! qtmux ! filesink location=test2.mp4 -e                                               
                                                                                
gst-launch-0.10 videotestsrc num-buffers=200 ! 'video/x-raw-yuv, width=(int)1280, height=(int)720, format=(fourcc)I420' ! nv_omx_h264enc quality-level=1 ! qtmux ! filesink location=test1.mp4 -e                                               
                                                                                
gst-launch-0.10 videotestsrc num-buffers=200 ! 'video/x-raw-yuv, width=(int)1280, height=(int)720, format=(fourcc)I420' ! nv_omx_h264enc quality-level=0 ! qtmux ! filesink location=test0.mp4 -e
  1. All there files are same size, I can’t find different content, how do I test different quality-level?
  2. Is there any documents to describe the detail compress rate of quality-level(0,1,2)?
  3. Does Gstreamer-1.0 support quality-level? I can’t find similar properties with gst-inspect-1.0 omxh264enc.