Directx SDK 枚举视频设备查找PID

时间：2010-10-15 来源：zhouli

代码 BOOL FindDevicesPid(long pid)
{
    BOOL myCamera_exist = FALSE;
    WCHAR CameraPid[256] = {0};   //摄像头PID值
    _itow( pid, CameraPid, 16 ); //十进制转化为十六进制存储在字符串中
    wstring sCameraPid(CameraPid);
    int length = sCameraPid.length();
    for(;length<4;length++)
        sCameraPid= L"0" + sCameraPid;
    sCameraPid= L"pid_"+sCameraPid;
    // 枚举是有视频设备
    ICreateDevEnum *pCreateDevEnum=0;
    HRESULT hr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,
        IID_ICreateDevEnum, (void**)&pCreateDevEnum);
    if(hr != NOERROR)
    {
        MessageBoxW(NULL,L"创建失败!",L"系统提示",NULL);
        return FALSE;
    }
    IEnumMoniker *pEm=0;
    hr = pCreateDevEnum->CreateClassEnumerator(CLSID_VideoInputDeviceCategory, &pEm, 0);
    if(hr != NOERROR)
    {
        MessageBoxW(NULL,L"没有视频设备!",L"系统提示",NULL);
        return FALSE;
    }
    pEm->Reset();
    ULONG cFetched;
    IMoniker *pM;
    while(hr = pEm->Next(1, &pM, &cFetched), hr==S_OK)
    {
        IPropertyBag *pBag=0;
        hr = pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag);
        if(SUCCEEDED(hr))
        {
            //读取设备名
            VARIANT var;
            var.vt = VT_BSTR;
            hr = pBag->Read(L"FriendlyName", &var, NULL);
            if (hr == NOERROR)
            {
                //读取显示名称，其中包含了设备PID和VID值
                //如：@device:pnp:\\?\usb#vid_1b17&pid_6687&mi_00#6&1d285357&0&0000#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\global
                WCHAR * wzDisplayName      = NULL;
                hr = pM->GetDisplayName( NULL , NULL, &wzDisplayName );
                wstring displayName = wzDisplayName;
                //查找摄像头PID是否正确
          if (displayName.find(sCameraPid) != wstring::npos)
                {
                    myCamera_exist = TRUE;
                    break;
                }
            }
        }
    }
    return myCamera_exist;
}

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