如何在 Windows 上获取视频捕获设备（网络摄像头）的列表？ (C++)

Question

所以我们有一个简单的 C++ win32 控制台应用程序。我们想要的只是打印可用的网络摄像头和其他视频捕获设备的列表。我们想尽可能多地使用 windows api - 没有外部库 - 毕竟 - 我们想要的只是打印出一个列表 - 而不是飞上月球！）怎么做？

我自己的研究： 我找到了这个official msdn sample，但我仍然不知道如何将设备列表输出到屏幕上=（（对不起 - 我是 C++ 新手）

...更多研究...

在一个关于主题的最简单的 ms 示例中找到了这个

HRESULT OnInitDialog(HWND hwnd, ChooseDeviceParam *pParam)
{
    HRESULT hr = S_OK;

    HWND hList = GetDlgItem(hwnd, IDC_DEVICE_LIST);

    // Display a list of the devices.

    for (DWORD i = 0; i < pParam->count; i++)
    {
        WCHAR *szFriendlyName = NULL;

        hr = pParam->ppDevices[i]->GetAllocatedString(
            MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME,
            &szFriendlyName,
            NULL
            );

        if (FAILED(hr))
        {
            break;
        }

        int index = ListBox_AddString(hList, szFriendlyName);

        ListBox_SetItemData(hList, index, i);

        CoTaskMemFree(szFriendlyName);
    }

看起来它应该可以完成这项工作，但我不知道如何将其包含到简单的命令行应用程序中以便输出数据...

---

也来自这个系列：

• How to get a list of video capture devices on linux? 和 special details on getting cameras NAMES 提供正确、经过测试的答案
• How to get a list of video capture devices on Mac OS? 正确，但我的答案尚未测试
• How to get a list of video capture devices on windows? 提供正确、经过测试的答案
• How to get a list video capture devices NAMES using Qt (crossplatform)?

Answer 1

这是列出 Windows 机器上连接的网络摄像头的 C++ 代码，无需任何额外的库

/*  List connected webcams on windows machine
Build: g++ cameralist.cpp -lstrmiids -lole32 -loleaut32
microsoft docs https://docs.microsoft.com/en-us/windows/win32/directshow/using-the-system-device-enumerator
*/

#include <windows.h>
#include <dshow.h>

HRESULT EnumerateDevices(REFGUID category, IEnumMoniker **ppEnum)
{
    // Create the System Device Enumerator.

    HRESULT hr;
    ICreateDevEnum *pDevEnum = NULL;
    hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,
                          IID_ICreateDevEnum, (void **)&pDevEnum);

    if (SUCCEEDED(hr))
    {
        // Create an enumerator for the category.
        hr = pDevEnum->CreateClassEnumerator(category, ppEnum, 0);
        if (hr == S_FALSE)
        {
            hr = VFW_E_NOT_FOUND; // The category is empty. Treat as an error.
        }
        pDevEnum->Release();
    }
    return hr;
}

void DisplayDeviceInformation(IEnumMoniker *pEnum)
{
    IMoniker *pMoniker = NULL;

    while (pEnum->Next(1, &pMoniker, NULL) == S_OK)
    {
        IPropertyBag *pPropBag;
        HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag));
        if (FAILED(hr))
        {
            pMoniker->Release();
            continue;
        }

        VARIANT var;
        VariantInit(&var);

        // Get description or friendly name.
        hr = pPropBag->Read(L"Description", &var, 0);
        if (FAILED(hr))
        {
            hr = pPropBag->Read(L"FriendlyName", &var, 0);
        }
        if (SUCCEEDED(hr))
        {
            printf("%S\n", var.bstrVal);
            VariantClear(&var);
        }

        hr = pPropBag->Write(L"FriendlyName", &var);
   
        hr = pPropBag->Read(L"DevicePath", &var, 0);
        if (SUCCEEDED(hr))
        {
            // The device path is not intended for display.
            printf("Device path: %S\n", var.bstrVal);
            VariantClear(&var);
        }

        pPropBag->Release();
        pMoniker->Release();
    }
}

int main()
{
    HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
    if (SUCCEEDED(hr))
    {
        IEnumMoniker *pEnum;

        hr = EnumerateDevices(CLSID_VideoInputDeviceCategory, &pEnum);
        if (SUCCEEDED(hr))
        {
            DisplayDeviceInformation(pEnum);
            pEnum->Release();
        }

        CoUninitialize();
    }
    return 0;
}

Answer 2

从显示的示例中，将以下代码复制到 dev.c 中。然后打开设置了所有 SDK 变量的命令行。在命令行链接到 ole32.lib 和 oleaut32.lib。然后它将显示所有设备。

cl dev.c ole32.lib oleaut32.lib

dev.exe 会在命令行给出列表。

#include <windows.h>
#include <dshow.h>

#pragma comment(lib, "strmiids")

HRESULT EnumerateDevices(REFGUID category, IEnumMoniker **ppEnum)
{
    // Create the System Device Enumerator.
    ICreateDevEnum *pDevEnum;
    HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL,  
        CLSCTX_INPROC_SERVER, IID_PPV_ARGS(&pDevEnum));

    if (SUCCEEDED(hr))
    {
        // Create an enumerator for the category.
        hr = pDevEnum->CreateClassEnumerator(category, ppEnum, 0);
        if (hr == S_FALSE)
        {
            hr = VFW_E_NOT_FOUND;  // The category is empty. Treat as an error.
        }
        pDevEnum->Release();
    }
    return hr;
}


void DisplayDeviceInformation(IEnumMoniker *pEnum)
{
    IMoniker *pMoniker = NULL;

    while (pEnum->Next(1, &pMoniker, NULL) == S_OK)
    {
        IPropertyBag *pPropBag;
        HRESULT hr = pMoniker->BindToStorage(0, 0, IID_PPV_ARGS(&pPropBag));
        if (FAILED(hr))
        {
            pMoniker->Release();
            continue;  
        } 

        VARIANT var;
        VariantInit(&var);

        // Get description or friendly name.
        hr = pPropBag->Read(L"Description", &var, 0);
        if (FAILED(hr))
        {
            hr = pPropBag->Read(L"FriendlyName", &var, 0);
        }
        if (SUCCEEDED(hr))
        {
            printf("%S\n", var.bstrVal);
            VariantClear(&var); 
        }

        hr = pPropBag->Write(L"FriendlyName", &var);

        // WaveInID applies only to audio capture devices.
        hr = pPropBag->Read(L"WaveInID", &var, 0);
        if (SUCCEEDED(hr))
        {
            printf("WaveIn ID: %d\n", var.lVal);
            VariantClear(&var); 
        }

        hr = pPropBag->Read(L"DevicePath", &var, 0);
        if (SUCCEEDED(hr))
        {
            // The device path is not intended for display.
            printf("Device path: %S\n", var.bstrVal);
            VariantClear(&var); 
        }

        pPropBag->Release();
        pMoniker->Release();
    }
}

void main()
{
    HRESULT hr = CoInitializeEx(NULL, COINIT_MULTITHREADED);
    if (SUCCEEDED(hr))
    {
        IEnumMoniker *pEnum;

        hr = EnumerateDevices(CLSID_VideoInputDeviceCategory, &pEnum);
        if (SUCCEEDED(hr))
        {
            DisplayDeviceInformation(pEnum);
            pEnum->Release();
        }
        hr = EnumerateDevices(CLSID_AudioInputDeviceCategory, &pEnum);
        if (SUCCEEDED(hr))
        {
            DisplayDeviceInformation(pEnum);
            pEnum->Release();
        }
        CoUninitialize();
    }
}

Answer 3

How to let user select a video recording device (web-cam) with OpenCV?

答案不是特定于 opencv 的