C++ DirectShow读取摄像头后然后保存图像数据

#include <stdio.h>

#include "camerads.h"

#include <highgui.h>

const char *g_szTitle = "Camera";

int main()
{
	// 1、考虑到已经存在了显示图像的窗口，那就不必再次驱动摄像头了，即便往下驱动那也是摄像头已被占用。
	if(IsWindowVisible(FindWindow(NULL, g_szTitle)))
	{
		return (-1);
	}

	//仅仅获取摄像头数目
	int m_iCamCount = CCameraDS::CameraCount();
	printf("There are %d cameras.\n", m_iCamCount);

	if(m_iCamCount == 0)
	{
		return (-1);
	}

	CCameraDS m_CamDS;

	//获取所有摄像头的名称
	for(int i = 0; i < m_iCamCount; i++)
	{
		char szCamName[1024];

		int retval = m_CamDS.CameraName(i, szCamName, sizeof(szCamName));

		if(retval >0)
		{
			printf("Camera #%d's Name is '%s'.\n", i, szCamName);
		}
		else
		{
			printf("Can not get Camera #%d's name.\n", i);
		}
	}

	// 2、考虑到如果有多个摄像头，或者又有其中某个或某几个正在被其它程序占有，故需要逐个遍历，
	// 直到找到可用的为止。
	int m_iCamNum = 0; // 摄像头编号

	IplImage *pFrame = NULL;

	while(m_iCamNum < m_iCamCount)
	{
		if((! m_CamDS.OpenCamera(m_iCamNum, false, 640, 480)) || ((pFrame = m_CamDS.QueryFrame()) == NULL))
		{
			m_iCamNum++;
		}
		else
		{ // 找到合适的摄像头，退出循环。
			break;
		}

		// 关闭摄像头，必须要关闭，因为即将要进行下一次的检测，检测前要清空当前的占用空间。
		m_CamDS.CloseCamera();
	}

	if(m_iCamNum == m_iCamCount)
	{
		fprintf(stderr, "Can not open camera or is used by another app.\n");

		return (-1);
	}

	cvNamedWindow(g_szTitle);
	//显示
	cvShowImage(g_szTitle, pFrame);

	printf("%d %d\n", m_CamDS.GetHeight(), m_CamDS.GetWidth());
	CvVideoWriter *vw = cvCreateVideoWriter("e:\\123.avi", CV_FOURCC('X', 'V', 'I', 'D'), 25, 
		CvSize(m_CamDS.GetWidth(), m_CamDS.GetHeight()));//视频的长宽应该和摄像头的长宽一致，否则总是生产不了AVI
	if (vw == NULL){
		printf("cvCreateVideoWriter failed\n");
		return 0;
	}

	DWORD dwTime1 = GetTickCount();
	int nWrite = 0;
	while(GetTickCount() - dwTime1 < 5000)
	{
		//获取一帧
		pFrame = m_CamDS.QueryFrame();
		if (pFrame == NULL){
			printf("QueryFrame Failed\n");
			break;
		}
		nWrite = cvWriteFrame(vw, pFrame);
		if (nWrite != 1){
			printf("WriteVideo Failed\n");
			break;
		}
		//显示
		cvShowImage(g_szTitle, pFrame);

		if (cvWaitKey(20) == 'q'){
			break;
		}
	}
	
	m_CamDS.CloseCamera(); //可不调用此函数，CCameraDS析构时会自动关闭摄像头
	cvReleaseVideoWriter(&vw);
	cvDestroyWindow(g_szTitle);

	return 0;
}