cvtColor把yuv420sp转RGB24

可以使用以下代码将YUV420SP图像转换为RGB24：

void YUV420SP_to_RGB24(unsigned char* yuv420sp, unsigned char* rgb24, int width, int height) {
    int frameSize = width * height;
    int i = 0, j = 0, y = 0;
    int uvp = 0, u = 0, v = 0;
    int r = 0, g = 0, b = 0;

    for (j = 0, y = 0; j < height; j++) {
        uvp = frameSize + (j >> 1) * width;
        u = 0;
        v = 0;
        for (i = 0; i < width; i++, y++) {
            int yvalue = (0xff & ((int) yuv420sp[y]));
            if (i % 2 == 0) {
                v = (0xff & yuv420sp[uvp++]) - 128;
                u = (0xff & yuv420sp[uvp++]) - 128;
            }
            r = (int) (yvalue + 1.370705 * v);
            g = (int) (yvalue - 0.698001 * v - 0.337633 * u);
            b = (int) (yvalue + 1.732446 * u);

            r = (r < 0) ? 0 : ((r > 255) ? 255 : r);
            g = (g < 0) ? 0 : ((g > 255) ? 255 : g);
            b = (b < 0) ? 0 : ((b > 255) ? 255 : b);

            rgb24[y * 3] = (unsigned char) (r);
            rgb24[y * 3 + 1] = (unsigned char) (g);
            rgb24[y * 3 + 2] = (unsigned char) (b);
        }
    }
}

其中，yuv420sp是输入的YUV420SP图像数据，rgb24是输出的RGB24图像数据，width和height分别是图像的宽度和高度。