OpenCV色フォーマット変換(BGR,YUV420, NV12)

conv.cpp

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

using namespace cv;

void save(const char *filename, const unsigned char * data, int size)
{
	FILE *fp = fopen(filename, "wb");
	fwrite(data, size, 1, fp);
	fclose(fp);
}

void convYUV420toNV12(unsigned char *dst, const unsigned char *src, int width, int height)
{
	/* for Y */
	memcpy(dst, src, width * height);
	dst += width * height;
	
	const unsigned char *srcU = src + width * height;
	const unsigned char *srcV = srcU + width * height / 4;

	for (int y = 0; y < height / 4; y++) {
		for (int x = 0; x < width; x++) {
			dst[y * (width * 2) + x * 2 + 0] = srcU[y * width + x];
			dst[y * (width * 2) + x * 2 + 1] = srcV[y * width + x];
		}
	}
}

int main()
{
	printf("Hello\n");

	/*  BGR: 4 x 4
	BGRBGRBGRBGR
	BGRBGRBGRBGR
	BGRBGRBGRBGR
	BGRBGRBGRBGR
	*/
	cv::Mat imageBGR = cv::imread(RESOURCE_DIR"lena.jpg");
	int width = imageBGR.cols;
	int height = imageBGR.rows;
	save("imageBGR.raw", imageBGR.data, width * height * 3);

	/* YUV420(planer) 4 x 4
	YYYY
	YYYY
	YYYY
	YYYY
	UUUU
	VVVV
	*/
	cv::Mat imageYUV;
	cv::cvtColor(imageBGR, imageYUV, CV_BGR2YUV_I420);
	save("imageYUV.raw", imageYUV.data, width * height * 1.5 * 1);

	/* NV12(semi-planer) 4 x 4
	YYYY
	YYYY
	YYYY
	YYYY
	UVUV
	UVUV
	*/
	unsigned char *imageNV12 = new unsigned char[width * height * 1.5];
	convYUV420toNV12(imageNV12, imageYUV.data, width, height);
	save("imageNV12.raw", imageNV12, width * height * 1.5 * 1);

	delete[] imageNV12;

	return 0;
}


/*
http://klabgames.tech.blog.jp.klab.com/archives/1054828175.html
*/