I noticed that there is ippiInterpolationType::ippCubic, but not bicubic.
Being a beginner in image processing I'd like to hear from the experts how one would achieve bicubic interpolation? I've read that bicubic is applying cubic filtering both horizontally and vertically.
Isn't it what cubic filtering does in IPP?
Yes, it is what cubic filtering does in IPP. The interpolation type ippCubic is two dimensional cubic filtering that is applying a cubic interpolation both horizontally and vertically.