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DIGITAL-LOGIC AG MSLB-P5 Manual V0.3

PRELIMINARY 93

4.11.15 How to crop input video (programming of acquisition rectangle)

Video acquisition rectangle is used to crop the unwanted video input data before the 69000 hardware scales it

and grabs it into off-screen buffer. This is also used to crop vertical blank interval data (Closed Caption or Tele

Text) from the NTSC video.

//-------------------------------------------------------------------------

// SetCropRect() : Sets cropping rectrangle on input video recctangle.

// +----------------+

// | +----------+ |

// | | | |

// | | CropRect | |

// | | | |

// | +----------+ |

// | Input Video |

// +----------------+

// Enter:

// lpRect Crop Rectangle withing Input Video rectangle (NTSC/PAL dependent)

// rCrop - local copy of Cropping Rectangle

// bVideoFlowingIn = 0 if video is not flowing into the port, 1 normally.

// Exit :

// Nothing

//-------------------------------------------------------------------------

void SetCropRect(LPRECTL lpRect)

{

UINT mr0e,mr0f,mr10,mr11,mr12,mr13,mr14,mr15;

union WORD16 u;

if(&rCrop != lpRect) rCrop = *lpRect; // copy crop rectangle into our area

if(!bVideoFlowingIn) return;

// Use NULL Rectangle done by static initialization

u.w = (USHORT)((int)rCrop.left);

mr0e = ((UINT)u.b[0] << 8) + MR_VIN_AQW_XL_L;

mr0f = ((UINT)u.b[1] << 8) + MR_VIN_AQW_XL_H;

u.w = (USHORT)((int)rCrop.right -1);

mr10 = ((UINT)u.b[0] << 8) + MR_VIN_AQW_XR_L;

mr11 = ((UINT)u.b[1] << 8) + MR_VIN_AQW_XR_H;

u.w = (USHORT)((int)rCrop.top);

mr12 = ((UINT)u.b[0] << 8) + MR_VIN_AQW_YT_L;

mr13 = ((UINT)u.b[1] << 8) + MR_VIN_AQW_YT_H;

u.w = (USHORT)((int)rCrop.bottom -1);

mr14 = ((UINT)u.b[0] << 8) + MR_VIN_AQW_YB_L;

mr15 = ((UINT)u.b[1] << 8) + MR_VIN_AQW_YB_H;

WritePortUshort(ulMrAddr,mr0e); // program Left

WritePortUshort(ulMrAddr,mr0f);

WritePortUshort(ulMrAddr,mr10); // program right

WritePortUshort(ulMrAddr,mr11);

WritePortUshort(ulMrAddr,mr12); // program top

WritePortUshort(ulMrAddr,mr13);

WritePortUshort(ulMrAddr,mr14); // program bottom

WritePortUshort(ulMrAddr,mr15);