What is the difference between vc10, vc11 and vc12 libraries in OpenCV?

They are different builds for each version of Microsoft's Visual Studio compiler.

• vc16: The compiler packaged with Visual Studio 2019
• vc15: The compiler packaged with Visual Studio 2017
• vc14: The compiler packaged with Visual Studio 2015
• vc12: The compiler packaged with Visual Studio 2013
• vc11: The compiler packaged with Visual Studio 2012
• vc10: The compiler packaged with Visual Studio 2010

It refers to MS Visual Studio version https://en.wikipedia.org/wiki/Microsoft_Visual_Studio#History.

It refers to Visual C++ version used for the build. x64 and x86 is the chip architecture 64 vs 32 bit.