之前在https://blog.csdn.net/fengbingchun/article/details/103507754 博文中介绍过如何在Linux获取usb视频设备的vendor id和product id，这里介绍在Windows下获取的方式：
1. 打开设备管理器，如下图所示，内置摄像头显示名为”Integrated Webcam”，插入的usb摄像头显示名为”Logitech HD Webcam C310”：
选中其中一个，如”Logitech HD Webcam C310”，点击右键，选中”属性”点击，–>详细信息，–>属性选择”硬件id”，可获取vid和pid值，如下图所示，十六进制vid为”046D”，pid为”081B”：
2. 通过执行ffmpeg获取，执行命令及执行结果如下图所示：
3. 通过Windows的SetupDiGetDeviceInstanceId函数可以获得所有usb设备的vid和vid，测试code如下：
int get_all_usb_devices_vid_pid()
{GUID *guidDev = (GUID*)&GUID_DEVCLASS_USB;HDEVINFO deviceInfoSet = SetupDiGetClassDevs(guidDev, NULL, NULL, DIGCF_PRESENT | DIGCF_PROFILE);CHAR buffer[4000];DWORD memberIndex = 0;while (true) {SP_DEVINFO_DATA deviceInfoData;ZeroMemory(&deviceInfoData, sizeof(SP_DEVINFO_DATA));deviceInfoData.cbSize = sizeof(SP_DEVINFO_DATA);if (SetupDiEnumDeviceInfo(deviceInfoSet, memberIndex, &deviceInfoData) == FALSE) {if (GetLastError() == ERROR_NO_MORE_ITEMS) {break;}}DWORD nSize = 0;SetupDiGetDeviceInstanceId(deviceInfoSet, &deviceInfoData, buffer, sizeof(buffer), &nSize);buffer[nSize] = '\0';fprintf(stdout, "%s\n", buffer);memberIndex++;}if (deviceInfoSet) {SetupDiDestroyDeviceInfoList(deviceInfoSet);}return 0;
}执行结果如下：
4. 提取FFmpeg源码中部分code，测试code如下：
std::unique_ptr<char[]> dup_wchar_to_utf8(wchar_t *w, int& len)
{len = WideCharToMultiByte(CP_UTF8, 0, w, -1, 0, 0, 0, 0);std::unique_ptr<char[]> s(new char[len]);WideCharToMultiByte(CP_UTF8, 0, w, -1, s.get(), len, 0, 0);return s;
}int parse_string(const std::string& src, std::string& vid, std::string& pid)
{int pos = src.find("vid_");if (pos == std::string::npos) return -1;vid.assign(src, pos + 4, 4);pos = src.find("pid_");if (pos == std::string::npos) return -1;pid.assign(src, pos + 4, 4);return 0;
}int get_usb_video_devices_vid_pid()
{CoInitialize(0);ICreateDevEnum *devenum = NULL;int r = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER, IID_ICreateDevEnum, reinterpret_cast<void**>(&devenum));if (r != S_OK) {fprintf(stdout, "fail to CoCreateInstance: %d\n", r);return -1;}IEnumMoniker *classenum = NULL;r = ICreateDevEnum_CreateClassEnumerator(devenum, CLSID_VideoInputDeviceCategory, (IEnumMoniker **)&classenum, 0);if (r != S_OK) {fprintf(stdout, "fail to ICreateDevEnum_CreateClassEnumerator: %d\n", r);return -1;}IBaseFilter *device_filter = NULL;IMoniker *m = NULL;while (!device_filter && IEnumMoniker_Next(classenum, 1, &m, NULL) == S_OK) {IPropertyBag *bag = NULL;VARIANT var;r = IMoniker_BindToStorage(m, 0, 0, IID_IPropertyBag, (void **)&bag);if (r != S_OK) {fprintf(stdout, "fail to IMoniker_BindToStorage: %d\n", r);return -1;}var.vt = VT_BSTR;r = IPropertyBag_Read(bag, L"FriendlyName", &var, NULL);if (r != S_OK) {fprintf(stdout, "fail to IPropertyBag_Read: %d\n", r);return -1;}int length;auto friendly_name = dup_wchar_to_utf8(var.bstrVal, length);fprintf(stdout, "friendly_name: %s\n", friendly_name.get());LPMALLOC co_malloc = NULL;r = CoGetMalloc(1, &co_malloc);if (r != S_OK) {fprintf(stdout, "fail to CoGetMalloc: %d\n", r);return -1;}IBindCtx *bind_ctx = NULL;r = CreateBindCtx(0, &bind_ctx);if (r != S_OK) {fprintf(stdout, "fail to CreateBindCtx: %d\n", r);return -1;}LPOLESTR olestr = NULL;r = IMoniker_GetDisplayName(m, bind_ctx, NULL, &olestr);if (r != S_OK) {fprintf(stdout, "fail to IMoniker_GetDisplayName: %d\n", r);return -1;}auto unique_name = dup_wchar_to_utf8(olestr, length);/* replace ':' with '_' since we use : to delineate between sources */std::for_each(unique_name.get(), unique_name.get() + length, [](char& ch) { if (ch == ':') ch = '_'; });fprintf(stdout, "unique_name: %s\n", unique_name.get());std::string src(unique_name.get()), vid, pid;parse_string(src, vid, pid);unsigned int value_vid, value_pid;std::istringstream(vid) >> std::hex >> value_vid;std::istringstream(pid) >> std::hex >> value_pid;fprintf(stdout, "usb device name: %s, vid: %s, value: %d; pid: %s, value: %d\n",friendly_name.get(), vid.c_str(), value_vid, pid.c_str(), value_pid);if (olestr && co_malloc)IMalloc_Free(co_malloc, olestr);if (bind_ctx)IBindCtx_Release(bind_ctx);if (bag)IPropertyBag_Release(bag);IMoniker_Release(m);}IEnumMoniker_Release(classenum);return 0;
}执行结果如下：
GitHub：https://github.com//fengbingchun/OpenCV_Test