RGB24 to YV12 conversion (from a DirectShow filter by Infognition) www.infognition.com

conv.cpp

HRESULT YV12ConverterFromRGB24::Convert(BYTE *pInData, BYTE *pOutData)
{
	const int swidth = width/2;
	const int sheight = height/2;
	BYTE* ydata = pOutData;
	BYTE* udata = pOutData + width * height;
	BYTE* vdata = pOutData + width * height * 5/4;
	for(int sy=0;sy<sheight;sy++) {
		const int ty = height-1-sy*2;
		BYTE *pSrc = &pInData[ty*3*width];
		BYTE *pSrc2 = &pInData[(ty-1)*3*width];
		for(int sx=0;sx<swidth; sx++) {
			//make 4 Y values and 1 U and V
			int R = pSrc[0], G = pSrc[1], B = pSrc[2];
			int Y = ( (  66 * R + 129 * G +  25 * B + 128) >> 8) +  16;
			int U = ( ( -38 * R -  74 * G + 112 * B + 128) >> 8) + 128;
			int V = ( ( 112 * R -  94 * G -  18 * B + 128) >> 8) + 128;
			ydata[sx*2] = Y;
			udata[sx] = U;
			vdata[sx] = V;

			R = pSrc[3]; G = pSrc[4]; B = pSrc[5];
			Y = ( (  66 * R + 129 * G +  25 * B + 128) >> 8) +  16;
			ydata[sx*2+1] = Y;

			pSrc += 6;

			R = pSrc2[0]; G = pSrc2[1]; B = pSrc2[2];
			Y = ( (  66 * R + 129 * G +  25 * B + 128) >> 8) +  16;
			ydata[sx*2+width] = Y;

			R = pSrc2[3]; G = pSrc2[4]; B = pSrc2[5];
			Y = ( (  66 * R + 129 * G +  25 * B + 128) >> 8) +  16;
			ydata[sx*2+width+1] = Y;

			pSrc2 += 6;
		}
		ydata += width*2;
		udata += swidth;
		vdata += swidth;
	}
	return S_OK;		
}