OpenCV中BGR转NV12

1.opencv代码jpg转换yuv420sp（nv12）

#include <stdio.h>
#include <opencv2/opencv.hpp>

int main(int argc, char **argv)
{
	// 检查输入参数
	if(argc != 2){
		std::cout << "Usage: img2yuv <image_path>" << std::endl;
		return -1;
	}

	// 读取输入图像
	cv::Mat image = cv::imread(argv[1]);
	int image_h = image.rows;
	int image_w = image.cols;
	int image_c = image.channels();
	cv::imshow("image", image);
	cv::waitKey();

	// 转换到I420
	cv::Mat I420;                                      // I420格式图像
	cv::cvtColor(image, I420, cv::COLOR_BGR2YUV_I420); // 转换I420格式

	uint8_t *pI420 = I420.ptr<uint8_t>();              // I420数据指针
	int32_t I420_y_s = image_h * image_w;              // I420中 Y长度
	int I420_uv_h = image_h / 2;                       // I420中UV高度
	int I420_uv_w = image_w / 2;                       // I420中UV宽度

	// 转换到NV12
	cv::Mat NV12 = cv::Mat(image_h * 3 / 2, image_w, CV_8UC1); // NV12格式图像
	uint8_t *pNV12 = NV12.ptr<uint8_t>();                      // NV12数据指针
	memcpy(pNV12, pI420, I420_y_s); // 拷贝I420中的Y数据到NV12中

	uint8_t *pI420_U = pI420 + I420_y_s;                // 移动I420中U分量指针到U数据头部
	uint8_t *pI420_V = pI420_U + I420_uv_h * I420_uv_w; // 移动I420中V分量指针到V数据头部
	pNV12 = pNV12 + I420_y_s;                           // 移动NV12指针到U数据头部
	for(int i = 0; i < I420_uv_h * I420_uv_w; i++){ // 遍历I420中UV分量数据，复制到NV12中
		// 把I420中U数据复制到NV12中U数据对应位置
		*pNV12 = *pI420_U;
		pNV12++;
		pI420_U++;

		// 把I420中V数据复制到NV12中V数据对应位置
		*pNV12 = *pI420_V;
		pNV12++;
		pI420_V++;
	}

	// 保存转换图像
	FILE *fp = fopen("output/result.yuv", "wb");
	int image_len = image_w * image_h * 3 / 2;
	fwrite(NV12.ptr<uint8_t>(), image_len, 1, fp);
	fclose(fp);

	// 读取转换图像
	fp = fopen("output/result.yuv", "rb");
	unsigned char *image_buf = new unsigned char[image_len];
	fread(image_buf, image_len, 1, fp);
	fclose(fp);

	// 显示转换图像
	cv::Mat image2 = cv::Mat(image_h * 3 / 2, image_w, CV_8UC1, image_buf);
	cv::cvtColor(image2, image2, cv::COLOR_YUV2BGR_NV12);
	cv::imshow("image2", image2);
	cv::waitKey();

	return 0;
}

2.ffmpeg jpg转换yuv420sp（nv12）

ffmpeg -i data/1_2688_1520.jpg -pix_fmt nv12 output/1_2688_1520.yuv

ffmpeg -y -s 2688x1520 -pix_fmt nv12 -i output/1_2688_1520.yuv output/1_2688_1520.jpg

参考地址：

https://blog.csdn.net/nodototao/article/details/120649916

https://www.cnblogs.com/dxscode/p/16196396.html

http://www.javashuo.com/article/p-znuvnhtl-dy.html

https://blog.csdn.net/zfjBIT/article/details/127395512

https://blog.csdn.net/u014613270/article/details/123448481

https://blog.51cto.com/u_15764210/5616675

https://www.fangwenw.com/soft/view-7624.html

https://www.jb51.cc/faq/1292067.html

https://blog.csdn.net/denghp83/article/details/37936643

https://www.cnblogs.com/chenpi/p/5128233.html

https://www.cnblogs.com/arthurchn/p/13489815.html