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 27CvCapture* 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;
}

通过传入参数实现打开那个视频和摄像头，当参数为 0 xxxx时，打开视频，参数为1 x打开第几个摄像头。

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。