I am using OpenCV 2.4.11 and I have 2 folders x64 and x86 both containing vc10, vc11 and vc12 folders, each containing lib folders with the libraries. The libraries look pre
It refers to Visual C++ version used for the build. x64 and x86 is the chip architecture 64 vs 32 bit.
It refers to MS visual stdio version https://en.wikipedia.org/wiki/Microsoft_Visual_Studio
They are different builds for each version of Microsoft's Visual Studio compiler.