Converts an RGB image to the YUV color model.
Syntax
Case 1: Operation on pixel-order data
IppStatus ippiRGBToYUV_<mod>(const Ipp8u* pSrc, int srcStep, Ipp8u* pDst, int dstStep, IppiSize roiSize);
Supported values for mod:
| 8u_C3R | 8u_AC4R |
Case 2: Operation on planar data
IppStatus ippiRGBToYUV_8u_P3R(const Ipp8u* const pSrc[3], int srcStep, Ipp8u* pDst[3], int dstStep, IppiSize roiSize);
Case 3: Conversion from pixel-order to planar data
IppStatus ippiRGBToYUV_8u_C3P3R(const Ipp8u* pSrc, int srcStep, Ipp8u* pDst[3],int dstStep, IppiSize roiSize);
IppStatus ippiRGBToYUV_8u_AC4P4R(const Ipp8u* pSrc, int srcStep, Ipp8u* pDst[4], int dstStep, IppiSize roiSize);
Parameters
pSrc |
Pointer to the source image ROI for pixel-order data. An array of pointers to the source image ROI in separate color planes in case of planar data. |
srcStep |
Distance in bytes between starts of consecutive lines in the source image. |
pDst |
Pointer to the destination ROI for pixel-order data. An array of pointers to destination buffers in separate color planes in case of planar data. |
dstStep |
Distance in bytes between starts of consecutive lines in the destination image. |
roiSize |
Size of the source and destination ROI in pixels. |
Description
The function ippiRGBToYUV is declared in the ippcc.h file. It operates with ROI (see Regions of Interest in Intel IPP).
This function converts the gamma-corrected R'G'B' image pSrc to the Y'U'V' image pDst (see Figure Converting an RGB image to YUV) according to the following formulas:
Y' = 0.299*R' + 0.587*G' + 0.114*B'
U' = -0.147*R' - 0.289*G' + 0.436*B' = 0.492*(B'-Y')
V' = 0.615*R' - 0.515*G' - 0.100*B' = 0.877*(R'-Y')
For digital RGB values in the range [0..255], Y' has the range [0..255], U varies in the range [-112..+112], and V in the range [-157..+157]. To fit in the range of [0..255], a constant value 128 is added to computed U and V values, and V is then saturated.
Example “Using the Function ippiRGBToYUV” shows how to use the function ippiRGBToYUV_8u_C3R.
Return Values
ippStsNoErr |
Indicates no error. Any other value indicates an error or a warning. |
ippStsNullPtrErr |
Indicates an error condition if pSrc or pDst pointer is NULL. |
ippStsSizeErr |
Indicates an error condition if roiSize has a field with a zero or negative value. |
Using the Function ippiRGBToYUV
Ipp8u src[9*3] = {255, 0, 0, 255, 0, 0, 255, 0, 0, 0, 255, 0, 0, 255, 0, 0, 255, 0, 0, 0, 255, 0, 0, 255, 0, 0, 255}; Ipp8u dst[9*3]; IppiSize roiSize = { 9, 3 }; ippiRGBToYUV_8u_C3R ( src, 9, dst, 9, roiSize );
Result:
255 0 0 255 0 0 255 0 0 0 255 0 0 255 0 0 255 0 src 0 0 255 0 0 255 0 0 255 77 122 130 0 127 127 17 194 113 0 255 0 0 255 0 0 255 0 "gamma-corrected" src 0 0 255 0 0 255 0 0 255 76 90 255 76 90 255 76 90 255 149 54 0 149 54 0 149 54 0 dst 29 239 102 29 239 102 29 239 102