UYVY to NV12 using VPP returns MFX_ERR_INVALID_VIDEO_PARAM

I am trying to use the VPP component to just do a color space conversion from UYVY to NV12, no de-interlacing or scaling, or other filters.  When I use the exact same input parameters with MFX_FOURCC_YUY2 everything works.  When I change mfxVideoParam.vpp.In.FourCC to MFX_FOURCC_UYVY, MFXVideoVPP::QueryIOSurf returns MFX_ERR_INVALID_VIDEO_PARAM.  I am using API level 1.25.

Are there any additional restrictions on converting from UYVY to NV12 that I am missing and may be causing this?