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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);
- }
来源:http://blog.csdn.net/carson2005/article/details/38351717