Generic YUV conversion (Visual Basic)

Generic YUV conversion provides the ability to convert any YUV format to any supported color space, using the YUV_PARAMS structure and adhering to the restrictions listed below. After defining the YUV format, you can proceed with the conversion normally, just like any other conversion. Use L_ClrConvert to perform the conversion and call L_ClrFree to free the conversion handle. Currently the conversion from any color space to Generic YUV is not supported.

Generic YUV conversion currently has the following restrictions:

1.	No sub-sampling of Y is supported
2.	The number of Y elements must be a multiple of both U, and V.
3.	With non-planar formats, vertical sub-sampling of Y, U, and V is not supported.
4.	No alignment supported in planar format; line width must not contain additional bytes.
5.	The horizontal subsampling periods of U, and V must be multiples of each other, and the vertical subsampling periods of U, and V must be multiples of each other.

Examples:

1.	Converting Y41P to RGB using Generic YUV Conversion:

Function GenericY41PToRGB(YUVData() As Byte, RGBData() As Byte, nWidth As Integer, nHeight As Integer) As Integer
   Dim ret As Integer
   Dim ClrHandle As Long
   Dim cnvParam As CONVERSION_PARAMS
   Dim pOff(12) As Long

   pOff(0) = 1
   pOff(1) = 3
   pOff(2) = 5
   pOff(3) = 7
   pOff(4) = 8
   pOff(5) = 9
   pOff(6) = 10
   pOff(7) = 11
   pOff(8) = 0
   pOff(9) = 4
   pOff(10) = 2
   pOff(11) = 6
   '(1,3,5,7,8,9,10,11,0,4,2,6)

   Dim YUVParamas As LPYUV_PARAMS
   With YUVParamas
      .uStructSize = Len(YUVParamas)
      .nMask = 0
      .nUh = 4
      .nUv = 1
      .nVh = 4
      .nVv = 1
      .pOffsets = VarPtr(pOff(0))
      .nMacroPixel = 8
      .nRange = YUVRANGE_FULL
      .bPlanar = 0
   End With

   cnvParam.uStructSize = Len(cnvParam)
   cnvParam.nQuantization = 0
   cnvParam.nMethod = USE_BUILTIN
   cnvParam.nActiveMethod = USE_BUILTIN
   cnvParam.pCmykParams = 0
   cnvParam.pLabParams = 0
   cnvParam.pYuvParams = VarPtr(YUVParamas)
   cnvParam.sInputProfile(0) = 0
   cnvParam.sOutputProfile(0) = 0

   ret = L_ClrInit (ClrHandle, CCS_YUV, CCS_RGB, cnvParam)
   ret = L_ClrConvert (ClrHandle, YUVData(0), RGBData(0), nWidth, nHeight, 0, 0)
   ret = L_ClrFree (ClrHandle)

   GenericY41PToRGB = ret

End Function

2.	Converting YVU9 (Planar) to RGB using Generic YUV Conversion:

Function GenericYVU9ToRGB(YUVData() As Byte, RGBData() As Byte, nWidth As Integer, nHeight As Integer) As Integer
   Dim ret As Integer
   Dim ClrHandle As Long
   Dim cnvParam As CONVERSION_PARAMS
   Dim pOff(0) As Long

   pOff(0) = PLANAR_YVU

   Dim YUVParamas As LPYUV_PARAMS
   With YUVParamas
      .uStructSize = Len(YUVParamas)
      .nMask = 0
      .nUh = 4
      .nUv = 1
      .nVh = 4
      .nVv = 1
      .pOffsets = VarPtr(pOff(0))
      .nMacroPixel = 8
      .nRange = YUVRANGE_FULL
      .bPlanar = 1
   End With

   cnvParam.uStructSize = Len(cnvParam)
   cnvParam.nQuantization = 0
   cnvParam.nMethod = USE_BUILTIN
   cnvParam.nActiveMethod = USE_BUILTIN
   cnvParam.pCmykParams = 0
   cnvParam.pLabParams = 0
   cnvParam.pYuvParams = VarPtr(YUVParamas)
   cnvParam.sInputProfile(0) = 0
   cnvParam.sOutputProfile(0) = 0

   ret = L_ClrInit (ClrHandle, CCS_YUV, CCS_RGB, cnvParam)
   ret = L_ClrConvert (ClrHandle, YUVData(0), RGBData(0), nWidth, nHeight, 0, 0)
   ret = L_ClrFree (ClrHandle)

   GenericYVU9ToRGB = ret

End Function