Hi techbull,
Please check how the time difference between gstreamer-0.10 and 1.0, for 1.0 hooking to fakesink(without rendering), it decodes in max performance and you will see short execution time and high CPU usage.
The comment above is wrong. The difference is from gstreamer frameworks as said in
https://devtalk.nvidia.com/default/topic/965272/jetson-tk1/omxh264dec-vs-nv_omx_h264dec/post/4987085/#4987085
The difference is not much in video rendering: