文章目录

• 1.前言
• 2.YUV数据格式
• 3.YUV与RGB的计算
• 4.总结

此文通过不同颜色的方格对一张图片中Y与UV值的对应情况进行了说明（颜色相同，表示对应关系）。

此文给出了NV21转Rgb的java和c版本，如下所示：
java版本

	/**
	 * NV21图像转RGB或BGR
	 * @param input NV21格式图像数据
	 * @param width 图像宽度
	 * @param height 图像高度
	 * @param output 输出图像缓冲区
	 * @param isRGB 为{@code true}转为RGB图像,否则转为BGR图像
	 */
	public void NV212RGBorBGR(byte[]input , int width , int height , byte[]output,boolean isRGB)
	{
	    int nvOff = width * height ;
	    int  i, j, yIndex = 0;
	    int y, u, v;
	    int r, g, b, nvIndex = 0;
	    for(i = 0; i < height; i++){
	        for(j = 0; j < width; j ++,++yIndex){
	            nvIndex = (i / 2)  * width + j - j % 2;
	            y = input[yIndex] & 0xff;
	            u = input[nvOff + nvIndex ] & 0xff;
	            v = input[nvOff + nvIndex + 1] & 0xff;

	            // yuv to rgb
	            r = y + ((351 * (v-128))>>8);  //r
	            g = y - ((179 * (v-128) + 86 * (u-128))>>8); //g
	            b = y + ((443 * (u-128))>>8); //b
	            
	            r = ((r>255) ?255 :(r<0)?0:r); 
	            g = ((g>255) ?255 :(g<0)?0:g);
	            b = ((b>255) ?255 :(b<0)?0:b);
	            if(isRGB){
	            	output[yIndex*3 + 0] = (byte) b;
	            	output[yIndex*3 + 1] = (byte) g;
	            	output[yIndex*3 + 2] = (byte) r;
	            }else{
	            	output[yIndex*3 + 0] = (byte) r;
	            	output[yIndex*3 + 1] = (byte) g;
	            	output[yIndex*3 + 2] = (byte) b;
	            }
	        }
	    }
	}

C版本

void NV212RGBorBGR(const uint8_t *input, int width, int height, uint8_t *output,bool isRGB)
{
	int nv_off = width * height;
	int  i, j, y_index = 0;
	int y, u, v;
	int r, g, b, nv_index = 0;
	for (i = 0; i < height; i++) {
		for (j = 0; j < width; j++,++y_index) {
			nv_index = i / 2 * width + j - j % 2;

			y = input[y_index];
			u = input[nv_off + nv_index];
			v = input[nv_off + nv_index + 1];

			r = y + ((351 * (v - 128)) >> 8);  //r
			g = y - ((179 * (v - 128) + 86 * (u - 128)) >> 8); //g
			b = y + ((443 * (u - 128)) >> 8); //b

			r = ((r>255) ? 255 : (r<0) ? 0 : r);
			g = ((g>255) ? 255 : (g<0) ? 0 : g);
			b = ((b>255) ? 255 : (b<0) ? 0 : b);
			if (isRGB) {
				output[y_index * 3 + 0] = (uint8_t)b;
				output[y_index * 3 + 1] = (uint8_t)g;
				output[y_index * 3 + 2] = (uint8_t)r;
			}
			else {
				output[y_index * 3 + 0] = (uint8_t)r;
				output[y_index * 3 + 1] = (uint8_t)g;
				output[y_index * 3 + 2] = (uint8_t)b;
			}
		}
	}
}

也可以参操此篇

void NV21_T_RGB(unsigned int width , unsigned int height , unsigned char *yuyv , unsigned char *rgb)
{
const int nv_start = width * height ;
    u32  i, j, index = 0, rgb_index = 0;
    u8 y, u, v;
    int r, g, b, nv_index = 0;
	
 
    for(i = 0; i <  height ; i++)
    {
		for(j = 0; j < width; j ++){
			//nv_index = (rgb_index / 2 - width / 2 * ((i + 1) / 2)) * 2;
			nv_index = i / 2  * width + j - j % 2;

			y = yuyv[rgb_index];
			u = yuyv[nv_start + nv_index ];
			v = yuyv[nv_start + nv_index + 1];
			
		
			r = y + (140 * (v-128))/100;  //r
			g = y - (34 * (u-128))/100 - (71 * (v-128))/100; //g
			b = y + (177 * (u-128))/100; //b
				
			if(r > 255)   r = 255;
			if(g > 255)   g = 255;
			if(b > 255)   b = 255;
       		if(r < 0)     r = 0;
			if(g < 0)     g = 0;
			if(b < 0)     b = 0;
			
			index = rgb_index % width + (height - i - 1) * width;
			rgb[index * 3+0] = b;
			rgb[index * 3+1] = g;
			rgb[index * 3+2] = r;
			rgb_index++;
		}
    }
    return 0;

文献一 图解YUV
文献二 代码
文献三 代码
文献四 Unity