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Generic YUV Conversion

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 LColor::Convert to perform the conversion and call LColor::Free to free the conversion object. 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 sub-sampling periods of U, and V must be multiples of each other, and the vertical sub-sampling periods of U, and V must be multiples of each other.

Examples:

  1. Converting Y41P to RGB using Generic YUV Conversion:

    L_VOID GenericY41PToRGB(L_UCHAR *pIn, L_UCHAR *pOut, L_INT nWidth, L_INT nHeight) 
    { 
       /*Declare an object*/ 
       LColor clr; 
       /*Declare a CONVERSION_PARAMS structure*/ 
       CONVERSION_PARAMS cpParams; 
       /*Declare a YUV_PARAMS structure*/ 
       YUV_PARAMS yuvParams; 
    /*Byte ordering of the format; for Y41P: 
       U0 Y0 V0 Y1 U4 Y2 V4 Y3 Y4 Y5 Y6 Y7 
       0    1    2    3    4    5    6    7    8   9    10  11 
    Put the Y component order first, then the U and V last as follows: 
       Y positions: 1,3,5,7,8,9,10,11 
       U positions: 0,4 
       V positions: 2,6   */ 
       L_INT pOff[] = {1,3,5,7,8,9,10,11,0,4,2,6}; 
       ZeroMemory (&cpParams, sizeof (CONVERSION_PARAMS)); 
       /*Determine the size of the structure*/ 
       yuvParams.uStructSize = sizeof(YUV_PARAMS); 
       /*Determine the horizontal sub-sampling of U */ 
       yuvParams.nUh = 4; 
       /*Determine the vertical sub-sampling of U */ 
       yuvParams.nUv = 1; 
       /*Determine the horizontal sub-sampling of V */ 
       yuvParams.nVh = 4; 
       /*Determine the vertical sub-sampling of V */ 
       yuvParams.nVv = 1; 
       /*Set the byte ordering*/ 
       yuvParams.pOffsets = pOff; 
       /*The YUV values range*/ 
       yuvParams.nRange = YUVRANGE_FULL; 
       /*This represents the macro pixels(smallest group of pixels allowed), which indicates how many actual pixels are in the macro pixel. This value is important only in non - planar format*/ 
       yuvParams.nMacroPixel = 8; 
       /*This is a Boolean value that represents the type of the YUV format (Planar = TRUE, or non - Planar = FALSE.)*/ 
       yuvParams.bPlanar =FALSE; 
       /*Fill the pYuvParams value with the address of the YUV_PARAMS structure*/ 
       cpParams.pYuvParams = &yuvParams; 
       /*Determine the size of CONVERSION_PARAMS*/ 
       cpParams.uStructSize = sizeof (CONVERSION_PARAMS); 
       /*Determine the type of conversion to be used in the conversion, for YUVGeneric, only use USE_BUILTIN*/ 
       cpParams.nMethod = USE_BUILTIN; 
       /*Determine the type of conversion to be activated. For YUVGeneric, 
       only USE_BUILTIN*/ 
       cpParams.nActiveMethod = USE_BUILTIN; 
       /*Initialize the conversion*/ 
       clr.Initialize (CCS_YUV, CCS_RGB, &cpParams); 
       /*Convert the buffers pIn to pOut*/ 
       clr.Convert (pIn, pOut, nWidth, nHeight, 0, 0); 
       /*Free the object*/ 
       clr.Free (); 
    } 

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

    L_VOID GenericYVU9ToRGB(L_UCHAR *pIn, L_UCHAR *pOut, L_INT nWidth, L_INT nHeight) 
    { 
       /*Declare an object*/ 
       LColor clr; 
       /*Declare a CONVERSION_PARAMS structure*/ 
       CONVERSION_PARAMS cpParams; 
       /*Declare a YUV_PARAMS structure*/ 
       YUV_PARAMS yuvParams; 
    /*This array of integers specifies the byte order of the yuv format. For planar formats it takes only a single value that represents the plane sequence in the buffer: 
       YUV, YVU, UYV, UVY, VYU, or VUY.*/ 
       L_INT pOff[] = {PLANAR_YVU}; /*PLANAR_YVU means the Y plane comes first in the buffer, then the V plane, and the U plane is last*/ 
       ZeroMemory (&cpParams, sizeof (CONVERSION_PARAMS)); 
       /*Determine the size of the structure*/ 
       yuvParams.uStructSize = sizeof(YUV_PARAMS); 
       /*Determine the horizontal sub-sampling of U*/ 
       yuvParams.nUh = 4; 
       /*Determine the vertical sub-sampling of U*/ 
       yuvParams.nUv = 4; 
       /*Determine the horizontal sub-sampling of V*/ 
       yuvParams.nVh = 4; 
       /*Determine the vertical sub-sampling of V*/ 
       yuvParams.nVv = 4; 
       /*This is a pointer to an integer. Pass the byte order array.*/ 
       yuvParams.pOffsets = pOff; 
       /*The range value determines the YUV range values. */ 
       yuvParams.nRange = YUVRANGE_FULL; 
       /*This represents the macro pixels(smallest group of pixels allowed) , which indicates how many actual pixels are in the macro pixel. This value is important only in non - planar format*/ 
       yuvParams.nMacroPixel = 16; 
       /*This is a Boolean value that represents the type of the YUV format (Planar, or non - Planar.)*/ 
       yuvParams.bPlanar = TRUE; 
       /*Pass the YUV_PARAMS structure address to the pYuvParams member of the CONVERSION_PARAMS structure.*/ 
       cpParams.pYuvParams = &yuvParams; 
       /*Determine the size of the CONVERSION_PARAMS structure.*/ 
       cpParams.uStructSize = sizeof (CONVERSION_PARAMS); 
       /*Determine the type of conversion to be used. For YUVGeneric, use only USE_BUILTIN*/ 
       cpParams.nMethod = USE_BUILTIN; 
       /*Determine the type of conversion to be activated. For YUVGeneric, use only USE_BUILTIN.*/ 
       cpParams.nActiveMethod = USE_BUILTIN; 
       /*Initialize the conversion*/ 
       clr.Initialize (CCS_YUV, CCS_RGB, &cpParams); 
       /*Convert the buffers pIn to pOut*/ 
       clr.Convert (pIn, pOut, nWidth, nHeight, 0, 0); 
       /*Free the object*/ 
       clr.Free (); 
    } 

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