OpenCV读取YUV420p文件并转换为Mat类型

参考文章：

http://blog.csdn.net/gxiaob/article/details/9718071

这里直接封装成了 Mat类型，增加了YUV400格式的转换：

void conv_yuv420_to_mat(Mat &dst, unsigned char* pYUV420, int width, int height)
{
    if (!pYUV420) {
        return;
    }

    IplImage *yuvimage,*rgbimg,*yimg,*uimg,*vimg,*uuimg,*vvimg;

    int nWidth = width;
    int nHeight = height;
    rgbimg = cvCreateImage(cvSize(nWidth, nHeight),IPL_DEPTH_8U,3);
    yuvimage = cvCreateImage(cvSize(nWidth, nHeight),IPL_DEPTH_8U,3);

    yimg = cvCreateImageHeader(cvSize(nWidth, nHeight),IPL_DEPTH_8U,1);
    uimg = cvCreateImageHeader(cvSize(nWidth/2, nHeight/2),IPL_DEPTH_8U,1);
    vimg = cvCreateImageHeader(cvSize(nWidth/2, nHeight/2),IPL_DEPTH_8U,1);

    uuimg = cvCreateImage(cvSize(nWidth, nHeight),IPL_DEPTH_8U,1);
    vvimg = cvCreateImage(cvSize(nWidth, nHeight),IPL_DEPTH_8U,1);

    cvSetData(yimg,pYUV420, nWidth);
    cvSetData(uimg,pYUV420+nWidth*nHeight, nWidth/2);
    cvSetData(vimg,pYUV420+long(nWidth*nHeight*1.25), nWidth/2);
    cvResize(uimg,uuimg,CV_INTER_LINEAR);
    cvResize(vimg,vvimg,CV_INTER_LINEAR);

    cvMerge(yimg,uuimg,vvimg,NULL,yuvimage);
    cvCvtColor(yuvimage,rgbimg,CV_YCrCb2RGB);

    cvReleaseImage(&uuimg);
    cvReleaseImage(&vvimg);
    cvReleaseImageHeader(&yimg);
    cvReleaseImageHeader(&uimg);
    cvReleaseImageHeader(&vimg);

    cvReleaseImage(&yuvimage);

    dst = Mat(rgbimg, true);
    cvReleaseImage(&rgbimg);
}

void conv_yuv400_to_mat(Mat &dst, unsigned char* pYUV400, int nWidth, int nHeight, int bit_depth)
{
    IplImage *yimg;

    if (!pYUV400) {
        return;
    }

    if (bit_depth == 8) {
        yimg = cvCreateImageHeader(cvSize(nWidth, nHeight), IPL_DEPTH_8U, 1);
    } else {
        yimg = cvCreateImageHeader(cvSize(nWidth, nHeight), IPL_DEPTH_16U, 1);
    }

    cvSetData(yimg, pYUV400, nWidth);

    dst = Mat(yimg, true);
    cvReleaseImageHeader(&yimg);
}


/* ---------------------------------------------------------------------------
 */
void DisplayYUV420(const char *s_path, int img_w, int img_h)
{
    printf("yuv file img_w: %d, img_h: %d \n", img_w, img_h);

    FILE* pFileIn = fopen(s_path, "rb");
    int bufLen = img_w * img_h * 3 / 2;
    unsigned char* pYuvBuf = new unsigned char[bufLen];
    int iCount = 0;


    for (iCount = 0; iCount < 200; iCount++) {
        Mat rgbImg;
        fread(pYuvBuf, bufLen * sizeof(unsigned char), 1, pFileIn);

        conv_yuv420_to_mat(rgbImg, pYuvBuf, img_w, img_h);

        cv::imshow("img", rgbImg);
        cv::waitKey(1);

        printf("%d \n", iCount);
    }

    delete[] pYuvBuf;
    fclose(pFileIn);
}

/* ---------------------------------------------------------------------------
 */
void DisplayYUV400(const char *s_path, int img_w, int img_h, int bit_depth)
{
    printf("yuv file img_w: %d, img_h: %d \n", img_w, img_h);

    FILE* pFileIn = fopen(s_path, "rb");
    int size_of_pixel = (bit_depth <= 8) ? 1 : 2;
    int bufLen = img_w * img_h * size_of_pixel;
    unsigned char* pYuvBuf = new unsigned char[bufLen];
    int iCount = 0;


    for (iCount = 0; iCount < 200; iCount++) {
        Mat rgbImg;
        fread(pYuvBuf, bufLen * sizeof(unsigned char), 1, pFileIn);

        conv_yuv400_to_mat(rgbImg, pYuvBuf, img_w, img_h, bit_depth);

        cv::imshow("img", rgbImg);
        cv::waitKey(0);

        printf("%d \n", iCount);
    }

    delete[] pYuvBuf;
    fclose(pFileIn);
}