The DDVIDEOPORTCAPS structure is defined as :-

struct DDVIDEOPORTCAPS {
DWORD dwSize;
DWORD dwFlags;
DWORD dwMaxWidth;
DWORD dwMaxVBIWidth;
DWORD dwMaxHeight;
DWORD dwVideoPortID;
DWORD dwCaps;
DWORD dwFX;
DWORD dwNumAutoFlipSurfaces;
DWORD dwAlignVideoPortBoundary;
DWORD dwAlignVideoPortPrescaleWidth;
DWORD dwAlignVideoPortCropBoundary;
DWORD dwAlignVideoPortCropWidth;
DWORD dwPreshrinkXStep;
DWORD dwPreshrinkYStep;
DWORD dwNumVBIAutoFlipSurfaces;
DWORD dwNumPreferredAutoflip;
WORD wNumFilterTapsX;
WORD wNumFilterTapsY;
};