opencv播放器和摄像头视频播放

在看《学习opencv》这本书，按着其中的例子和写了一个播放器和摄像头播放，代码如下

#include <opencv/cv.h>
#include <opencv/highgui.h>
#include <iostream>
#include <sstream>

using namespace std;
using namespace cv;


#define ESC 27

CvCapture* g_cvFileCap = 0;
CvCapture* g_cvCameraCap = 0;
int g_pos = 0;



int String2Int(const string& str_)
{
    int _re = 0;
    stringstream _ss;
    _ss << str_;
    _ss >> _re;
    return _re;
}


void OnTrackbarSlide(int nPos_)
{
    cvSetCaptureProperty(g_cvFileCap, CV_CAP_PROP_POS_FRAMES, nPos_);
}

int main(int argc, char* argv[])
{
    if (argc < 3)
    {
        return -1;
    }

    int _re = String2Int(argv[1]);
    if (_re == 0)
    {
        g_cvFileCap = cvCreateFileCapture(argv[2]);
        if (g_cvFileCap != NULL)
        {
            cvNamedWindow("AVWidget");
            cvMoveWindow("AVWidget", 100, 100);
            int _nFrames = cvGetCaptureProperty(g_cvFileCap, CV_CAP_PROP_FRAME_COUNT);
            cvCreateTrackbar("Pos", "AVWidget", &g_pos, _nFrames, OnTrackbarSlide);
            while (1) {
                IplImage* _frame = cvQueryFrame(g_cvFileCap);
                if (_frame != NULL)
                {
                    if (ESC == waitKey(1000 / 25))
                    {
                        break;
                    }
                    cvSmooth(_frame, _frame);
                    cvShowImage("AVWidget", _frame);
                    cvSetTrackbarPos("Pos", "AVWidget", g_pos++);

                }

            }


        }
        cvReleaseCapture(&g_cvFileCap);
    } else {
        int _index = String2Int(argv[2]);
        g_cvCameraCap = cvCreateCameraCapture(_index);
        if (g_cvCameraCap != NULL)
        {
            cvNamedWindow("CamWidget");
            cvMoveWindow("CamWidget", 100, 100);
            while (1) {
                IplImage* _frame = cvQueryFrame(g_cvCameraCap);
                if (_frame != NULL)
                {
                    if (ESC == waitKey(1000 / 25))
                    {
                        break;
                    }
                    cvSmooth(_frame, _frame);
                    cvShowImage("CamWidget", _frame);
                }

            }
        }
        cvReleaseCapture(&g_cvCameraCap);
    }

    return 0;
}

效果行。打开摄像头就算了。

其实使用opencv很方便。通过cvCreateFileCapture和cvQueryFrame就完成了视频文件的读取。操作摄像头唯一的不同是cvCreateCameraCapture，很方便。