Developer Reference

  • 2020
  • 10/21/2020
  • Public Content
Contents

RGBToYUV

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*
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
);
Include Files
ippcc.h
Domain Dependencies
Headers:
ippcore.h
,
ippvm.h
,
ipps.h
,
ippi.h
Libraries:
ippcore.lib
,
ippvm.lib
,
ipps.lib
,
ippi.lib
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
This function 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.
Converting an RGB image to YUV
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.

Example

The code example below shows how to use the function
ippiRGBToYUV_8u_C3R
.
# define nChannels 3 int main () { Ipp 8 u src [3*3* nChannels ] = { 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}; Ipp 8 u dst [3*3* nChannels ]; IppiSize roiSize = { 3, 3 }; IppStatus st = ippStsNoErr ; int srcStep = 3* nChannels ; int dstStep = 3* nChannels ; st = ippiRGBToYUV _8 u _ C 3 R ( src , srcStep , dst , dstStep , roiSize ); if ( st == ippStsNoErr){ printf("\n ************* passed ****************\n"); }else{ printf("\n ************* failed ****************\t"); } return 0; }
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 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

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804