Hi,
Intel Media SDK supports color space conversion from RGB(32)->NV12, YUY2->NV12 and YV12->NV12.
More details on how to use VPP to perform conversion is described in the Media SDK manuals.
There is also a vpp sample part of the SDK that can be used as reference.
If color space conversion is needed beyond the ones supported by Media SDK VPP then you can explore the capabilities of Intel Integrated Performance Primitives (IPP) which provides a wide range of conversion routines.
Regards,
Petter