Convert from RGB to YCbCr with 4:2:0 sampling
SSE2
| FwStatus | fwiRGBToYCbCr420_8u_C3P3R | ( | const Fw8u * pSrc, int srcStep, Fw8u * const pDst[3], int dstStep[3], FwiSize roiSize ); |
| dstStep[3] | Destination three-channel planar buffer step size (array values define width of each plane in bytes). | |
| pDst[3] | Pointer to a location in a three-channel planar destination buffer (array values point to a location in each plane). | |
| pSrc | Pointer to a location in a source buffer. | |
| roiSize | Specifies the height and width of an ROI. | |
| srcStep | Source buffer step size (width of the buffer in bytes). |
This function steps through an ROI in a source buffer, converts the source data from the RGB color model to the YCbCr color space with 4:2:0 chroma subsampling, and writes the converted data to a destination buffer.
A gamma-corrected RGB image (pSrc) is converted to a YCbCr image with 4:2:0 chroma subsampling.
Y = 0.257*R + 0.504*G + 0.098*B + 16 Cb = -0.148*R - 0.291*G + 0.439*B + 128 Cr = 0.439*R - 0.368*G - 0.071*B + 128
The input RGB contains the range [0 to 255].
The output Y nominally contains the range [16 to 235].
The output Cb and Cr contains the range [16 to 240], with 128 corresponding to zero.