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;
}