Disable the alpha bitmap. This flag cannot be combined with any other flags.
VMR9AlphaBitmap_hDC
The bitmap is specified as a GDI device context (HDC) in the hdc member of the VMR9AlphaBitmap structure. If this flag is not present, the bitmap is specified as a Direct3D IDirect3DSurface9 pointer in the pDDS member of the structure.
VMR9AlphaBitmap_EntireDDS
Use the entire Direct3D surface. The rSrc member of the VMR9AlphaBitmap structure is ignored. This flag cannot be combined with the VMR9AlphaBitmap_hDC flag.
VMR9AlphaBitmap_SrcColorKey
Indicates that the srcClrKey member is valid and should be used when blending. This flag cannot be used with a Direct3D surface that contains per-pixel alpha (D3DFMT_A8R8G8B8 format).
VMR9AlphaBitmap_SrcRect
Indicates that the rSrc member is valid and specifies a sub-rectangle of the original image to be blended. This flag is only valid for the IVMRMixerBitmap9::UpdateAlphaBitmapParameters method.
VMR9AlphaBitmap_FilterMode
Indicates that the dwFilterMode member is valid and should be used to overide the VMR filter's default filtering method.