cv::Mat到YUV420的转换

来源：互联网发布：linux 查ip 编辑：程序博客网时间：2024/06/05 19:34

某些特定场合我们会经常遇到yuv420格式的视频文件，这种视频帧无法直接用于opencv，故而，需要进行格式转换；幸运的是，opencv提供了rgb到yuv420的格式转换函数；下面给出基本用法；

函数1：读取avi格式的视频文件，转换成Yuv420格式，并写入文件；

void WriteYuv(){cv::VideoCapture vc;bool flag = vc.open("S1000008.avi");if (!flag){printf("avi file open error \n");system("pause");exit(-1);}int frmCount = vc.get(CV_CAP_PROP_FRAME_COUNT);frmCount -= 5;printf("frmCount: %d \n", frmCount);int w = vc.get(CV_CAP_PROP_FRAME_WIDTH);int h = vc.get(CV_CAP_PROP_FRAME_HEIGHT);int bufLen = w*h*3/2;unsigned char* pYuvBuf = new unsigned char[bufLen];FILE* pFileOut = fopen("result.yuv", "w+");if (!pFileOut){printf("pFileOut open error \n");system("pause");exit(-1);}printf("pFileOut open ok \n");for (int i=0; i<frmCount; i++){printf("%d/%d \n", i+1, frmCount);cv::Mat srcImg;vc>>srcImg;cv::imshow("img", srcImg);cv::waitKey(1);cv::Mat yuvImg;cv::cvtColor(srcImg, yuvImg, CV_BGR2YUV_I420);memcpy(pYuvBuf, yuvImg.data, bufLen*sizeof(unsigned char));fwrite(pYuvBuf, bufLen*sizeof(unsigned char), 1, pFileOut);}fclose(pFileOut);delete[] pYuvBuf;}

函数二，读取yuv420格式的文件，转换成cv::Mat格式，并予以显示：

void DisplayYUV(){int w = 1280;int h = 720;printf("yuv file w: %d, h: %d \n", w, h);FILE* pFileIn = fopen("result.yuv", "rb+");int bufLen = w*h*3/2;unsigned char* pYuvBuf = new unsigned char[bufLen];int iCount = 0;for(int i=0; i<200; i++){fread(pYuvBuf, bufLen*sizeof(unsigned char), 1, pFileIn);cv::Mat yuvImg;yuvImg.create(h*3/2, w, CV_8UC1); memcpy(yuvImg.data, pYuvBuf, bufLen*sizeof(unsigned char));cv::Mat rgbImg;cv::cvtColor(yuvImg, rgbImg, CV_YUV2BGR_I420);cv::imshow("img", yuvImg);cv::waitKey(1);printf("%d \n", iCount++);}delete[] pYuvBuf;fclose(pFileIn);}

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