SDL里面怎么把一张图转成YUV模式

RGBQUAD YUVtoRGB(RGBQUAD lYUVColor)

{

	int U,V,R,G,B;

	float Y = lYUVColor.rgbRed;

	U = lYUVColor.rgbGreen - 128;

	V = lYUVColor.rgbBlue - 128;



//	R = (int)(1.164 * Y + 2.018 * U);

//	G = (int)(1.164 * Y - 0.813 * V - 0.391 * U);

//	B = (int)(1.164 * Y + 1.596 * V);

	R = (int)( Y + 1.403f * V);

	G = (int)( Y - 0.344f * U - 0.714f * V);

	B = (int)( Y + 1.770f * U);



	R= min(255,max(0,R));

	G= min(255,max(0,G));

	B= min(255,max(0,B));

	RGBQUAD rgb={(BYTE)B,(BYTE)G,(BYTE)R,0};

	return rgb;

}

RGBQUAD RGBtoYUV(RGBQUAD lRGBColor)

{

	int Y,U,V,R,G,B;

	R = lRGBColor.rgbRed;

	G = lRGBColor.rgbGreen;

	B = lRGBColor.rgbBlue;



//	Y = (int)( 0.257 * R + 0.504 * G + 0.098 * B);

//	U = (int)( 0.439 * R - 0.368 * G - 0.071 * B + 128);

//	V = (int)(-0.148 * R - 0.291 * G + 0.439 * B + 128);

	Y = (int)(0.299f * R + 0.587f * G + 0.114f * B);

	U = (int)((B-Y) * 0.565f + 128);

	V = (int)((R-Y) * 0.713f + 128);



	Y= min(255,max(0,Y));

	U= min(255,max(0,U));

	V= min(255,max(0,V));

	RGBQUAD yuv={(BYTE)V,(BYTE)U,(BYTE)Y,0};

	return yuv;

}