YUYV转RGB

  YUYV是YUV的一种一个像素占用两个字节，存放顺序为[Y0 U0][Y1 V0][Y2 U1][Y3 V1].....

  Y表示亮度，UV是色差信号奇数（在前）和偶数（在后）像素共用色差信号UV

  下面是用查表法转换YUYV(YUV422)为RGB32位的代码

int y_table[256];//查表法
int v_r_table[256];
int v_g_table[256];
int u_g_table[256];
int u_b_table[256];

unsigned int limit_table[256*3];


__forceinline unsigned int LimitToUnsigned8Bits(int value)
{
    if (value > 255)
        return 255;
    else if (value < 0)
        return 0;
    else
        return value;
}


void InitTable()
{
    for(int i=0;i<=255;i++)
    {
        y_table[i]=(i-16)*1192;
        v_r_table[i]=(i-128)*1634;
        v_g_table[i]=(i-128)*833;
        u_g_table[i]=(i-128)*401;
        u_b_table[i]=(i-128)*2065;
    }
    for (int i=0;i<256*3;i++)
    {
        limit_table[i]=LimitToUnsigned8Bits(i-256);
    }

}


__forceinline unsigned int ConvertYUVPixelToRGB(unsigned char yComponent,unsigned char uComponent,unsigned char vComponent)
{
    //转换公式
    /*
    B= 1.164*(Y-16) + 2.018*(U-128);      为了提高速度，放大后使用整数计算，同时移位10位相当于放大缩小1024倍
    G= 1.164*(Y-16) - 0.380*(U-128) - 0.813*(V-128);
    R= 1.164*(Y-16) + 1.159*(V-128);
    */


    //原版代码
    //int y = yComponent - 16;
    //int u = uComponent - 128;
    //int v = vComponent - 128;
    //int r = LimitToUnsigned8Bits((1192 * y + 1634 * v) >> 10);
    //int g = LimitToUnsigned8Bits((1192 * y- 833 * v - 401 * u) >> 10);
    //int b = LimitToUnsigned8Bits((1192 * y + 2065 * u) >> 10);
    //return (255 << 24) | (r << 16) | (g << 8) | b;

    int y1192=y_table[yComponent];
    int r = limit_table[((y1192 + v_r_table[vComponent]) >> 10)+256];//可能小于0，先取正
    int g = limit_table[((y1192 - v_g_table[vComponent] - u_g_table[uComponent]) >> 10)+256];
    int b = limit_table[((y1192 + u_b_table[uComponent]) >> 10)+256];

    return (255 << 24) | (r << 16) | (g << 8) | b;
}


void ConvertBitmapFromYUYV(int width, int height, unsigned char *bufferIn,unsigned int *bufferOut)
{
    for (int pixel = 0; pixel < width * height; pixel += 2) 
    {
        unsigned char y1 = *bufferIn++;
        unsigned char u = *bufferIn++;
        unsigned char y2 = *bufferIn++;
        unsigned char v = *bufferIn++;
        //unsigned int a=ConvertYUVPixelToRGB(y1, u, v);
        *bufferOut++ = ConvertYUVPixelToRGB(y1, u, v);
        *bufferOut++ = ConvertYUVPixelToRGB(y2, u, v);

    }
}