What are the limits of openmax encoder/decoder on Raspberry PI?

[Augusto Destrero]

Hi there,
what are the performance limits of openmax encoder/decoder on Raspberry PI?

I explain better my question with an example: is it possibile to decode a 
mpeg4 FULL HD 30fps file and concurrently re-encoding it in h264 using 
gstreamer openmax in real time?

I have a performance problem decoding a FULL HD video stream in real time and 
I suspect the bottleneck is in the hardware decoder/encoder of the Rpi. The 
CPU idle is good, but the hardware decoder/encoder doesn't show itself there, 
is it?

How can I see if the performance limit of the hardware is reached? Is there 
some logging mechanism?

Thank you for your help and let me know if you need more information!
Augusto