BGRToYCbCr420

Converts a BGR image to the YCbCr image with 4:2:0 sampling for ITU-R BT.709 HDTV signal.

Syntax

IppStatus ippiBGRToYCbCr420_709HDTV_8u_AC4P3R(const Ipp8u* pSrc, int srcStep, Ipp8u* pDst[3], int dstStep[3], IppiSize roiSize);

Parameters

pSrc	Pointer to the source image ROI.
srcStep	Distance in bytes between starts of consecutive lines in the source image.
pDst	An array of pointers to ROI in separate planes of the destination image.
dstStep	An array of distances in bytes between starts of consecutive lines in the destination image planes.
roiSize	Size of the source and destination ROI in pixels.

Description

The function ippiBGRToYCrCb420_709HDTV is declared in the ippcc.h file. It operates with ROI (see Regions of Interest in Intel IPP).

This function converts a four-channel gamma-corrected B'G'R' image pSrc to the planar Y'Cb'Cr' image pDst for digital component video signals complied with the ITU-R BT.709 Recommendation [ITU709] for high-definition TV (HDTV). The source image pixel values are in the range [16..235]. The conversion is performed according to the following formulas [Jack01]:

Y' = 0.213*R' + 0.715*G' + 0.072*B'

Cb' = -0.117*R' - 0.394*G' + 0.511*B' + 128

Cr' = 0.511*R' - 0.464*G' - 0.047*B' + 128

The values of Y' of the destination image are in the range [16..235], the values of Cb', Cr' are in the range [16..240]. They should be saturated at the 1 and 254 levels.

The destination image pDst has the 4:2:0 sampling format (see Table “Planar Image Formats” for more details).

The values of roiSize.width and roiSize.height should be multiples of 2. Otherwise, the function reduces their original values to the nearest multiples of 2, performs the operation, and returns a warning message.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr	Indicates an error condition if pSrc or pDst is NULL.
ippStsSizeErr	Indicates an error condition if roiSize.width is less than 2 or roiSize.height is less than 2.
ippStsDoubleSize	Indicates a warning if roiSize has a field that is not a multiple of 2.