在做场景合并等情况下，需要用到两个或者两个以上的摄像头。虽然可以用一个简单的设置函数
VideoCapture capture(int index);去设置相应的设备ID，但是这个需要你知道设备摄像头的ID号，虽然一般电脑自带的摄像头ID为0，不同的USB插口有不同的ID号，我还是遇到有些奇葩的电脑其摄像头ID的值不是0；
所以还是觉得有必要去获取一下摄像头的ID号，以下的源代码是借鉴别人的，主要是从videocapture的源代码找到的。
1 #include 2 #include 3 #include "windows.h" 4 #include "dshow.h" 5 #include 6 7 #pragma comment(lib, "strmiids.lib") 8 #pragma comment(lib, "quartz.lib") 9 10 using namespace cv; 11 using namespace std; 12 13 int listDevices(vector& list) { 14 15 //COM Library Initialization 16 //comInit(); 17 18 //if (!silent) DebugPrintOut(" VIDEOINPUT SPY MODE! "); 19 20 21 ICreateDevEnum *pDevEnum = NULL; 22 IEnumMoniker *pEnum = NULL; 23 int deviceCounter = 0; 24 CoInitialize(NULL); 25 26 HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, 27 CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, 28 reinterpret_cast(&pDevEnum)); 29 30 31 if (SUCCEEDED(hr)) 32 { 33 // Create an enumerator for the video capture category. 34 hr = pDevEnum->CreateClassEnumerator( 35 CLSID_VideoInputDeviceCategory, 36 &pEnum, 0); 37 38 if (hr == S_OK) { 39 40 printf("SETUP: Looking For Capture Devices "); 41 IMoniker *pMoniker = NULL; 42 43 while (pEnum->Next(1, &pMoniker, NULL) == S_OK) { 44 45 IPropertyBag *pPropBag; 46 hr = pMoniker->BindToStorage(0, 0, IID_IPropertyBag, 47 (void**)(&pPropBag)); 48 49 if (FAILED(hr)) { 50 pMoniker->Release(); 51 continue; // Skip this one, maybe the next one will work. 52 } 53 54 55 // Find the description or friendly name. 56 VARIANT varName; 57 VariantInit(&varName); 58 hr = pPropBag->Read(L"Description", &varName, 0); 59 60 if (FAILED(hr)) hr = pPropBag->Read(L"FriendlyName", &varName, 0); 61 62 if (SUCCEEDED(hr)) 63 { 64 65 hr = pPropBag->Read(L"FriendlyName", &varName, 0); 66 67 int count = 0; 68 char tmp[255] = { 0 }; 69 //int maxLen = sizeof(deviceNames[0]) / sizeof(deviceNames[0][0]) - 2; 70 while (varName.bstrVal[count] != 0x00 && count < 255) 71 { 72 tmp[count] = (char)varName.bstrVal[count]; 73 count++; 74 } 75 list.push_back(tmp); 76 //deviceNames[deviceCounter][count] = 0; 77 78 //if (!silent) DebugPrintOut("SETUP: %i) %s ", deviceCounter, deviceNames[deviceCounter]); 79 } 80 81 pPropBag->Release(); 82 pPropBag = NULL; 83 84 pMoniker->Release(); 85 pMoniker = NULL; 86 87 deviceCounter++; 88 } 89 90 pDevEnum->Release(); 91 pDevEnum = NULL; 92 93 pEnum->Release(); 94 pEnum = NULL; 95 } 96 97 //if (!silent) DebugPrintOut("SETUP: %i Device(s) found ", deviceCounter); 98 } 99 100 //comUnInit();101 102 return deviceCounter;103 }104 105 int main()106 {107 vector list;108 listDevices(list);109 int capid0 = 0, capid1 = 0;110 cout
