I would like to know whether IPP libraries use the inbuilt GPU capabilities for decoding Or it use only the CPU capabilities?
I have a corei7 machine which has inbuilt Intel HD Graphic 4000 GPU. So if i use IPP7.1 libaries on this machine then will it use only CPU for decoing or it will use GPU also?
Is there any way to allow (if it doesnt use already) or disallow (if it already use) the GPU for decoding?
Do you mean media (video for example) decoding? Nevertheless, IPP 7.1 doesn't deal with integrated graphics GPU at all. Starting with 8.0, IPP stepped to GPU (look at IPP Preview for example), but IPP's GPU-enabled functionality concerns image (or, frame) processing only. For GPU-based video encoding/decoding you should refer to Intel Media SDK.