As many Intel IPP functions have to meet the bit-exact requirement, image processing functions use rounding. The default rounding mode for all functions can be described as "nearest even", that is the fixed point number x=N + α, 0 ≤ α < 0, where N is an integer number, is rounded as given by:
For example, 1.5 is rounded to 2, and 2.5 to 2.
Some image processing functions have additional rounding modes, which are set by the parameter roundMode.