MFC实现ffmpeg流媒体数据推送与接收（1.获取设备）

         本篇文章是基于ffmpeg的一个应用实例。做过流媒体的同学对于ffmepg比较了解，这里就不做介绍。直接进入实例分析：

         我们这次实现ffmpeg.exe解析桌面，摄像头，麦克风设备推送rtmp流到nginx，通过代码从流媒体服务器接收数据流解析并播放。那么第一步我们就要获取我们设备。桌面我们可以使用gdigrab来获取，考虑一些原因摄像头麦克风使用的dshow。那么本节就用MFC代码获取dshow相关的设备名称。

         CStringGetFirstCaptureDevices(const GUID devicesCLSID)

{

         //enumerate all video capture devices

         ICreateDevEnum*pCreateDevEnum = NULL;

         HRESULThr = CoCreateInstance(CLSID_SystemDeviceEnum, NULL, CLSCTX_INPROC_SERVER,

                   IID_ICreateDevEnum,(void**)&pCreateDevEnum);

 

         IEnumMoniker*pEm = NULL;

         hr= pCreateDevEnum->CreateClassEnumerator(devicesCLSID, &pEm, 0);

         if(hr != NOERROR)

                   return0;

 

         CStringstrDevicesName;

         ULONGcFetched;

         IMoniker*pM = NULL;

         if(hr= pEm->Next(1, &pM, &cFetched), hr==S_OK)

         {

                   LPOLESTRstrPidvid = NULL;

                   hr= pM->GetDisplayName(0, 0, &strPidvid); //获取ID信息

                   if(SUCCEEDED(hr))

                   {

                            //这里获取了一下设备的ID

                            USES_CONVERSION;//OLE2T

                            CStringsPidvid = strPidvid;

                            stringstr = T2A(sPidvid);

                            stringresult;

                            staticconst regex re("(vid_[0-9a-f]{4}&pid_[0-9a-f]{4})",regex::icase);

                            smatchmatch;

                            if(regex_search(str, match, re) && match.size() > 1)

                            {

                                     result= match.str(1);

                            }

                            else

                            {

                                     result= string("");

                            }

                            CStringstrPid(result.c_str());

                            strPid.MakeUpper();//全部大写

 

                            IPropertyBag*pBag=0;

                            hr= pM->BindToStorage(0, 0, IID_IPropertyBag, (void **)&pBag);

                            if(SUCCEEDED(hr))

                            {

                                     VARIANTvar;

                                     var.vt= VT_BSTR;

                                     hr= pBag->Read(L"FriendlyName", &var, NULL); //还有其他属性,像描述信息等等...

                                     if(hr== NOERROR)

                                     {

                                               //获取设备名称     

                                               chardevices_name[1024];

                                               WideCharToMultiByte(CP_ACP,0,var.bstrVal,-1,devices_name, sizeof(devices_name) ,"",NULL);

                                               strDevicesName= CString(devices_name);

 

                                               SysFreeString(var.bstrVal);                                 

                                     }

                                     pBag->Release();

                            }

                   }

                   pM->Release();

         }

         pEm->Release();

         pCreateDevEnum->Release();

         returnstrDevicesName;

}

通过传递CLSID_VideoInputDeviceCategory获取第一个摄像头设备名，传递CLSID_AudioInputDeviceCategory获取第一个麦克风设备名。由于简单应用我们就只获取第一设备。使用时加上头文件Dshow.h,regex.h及strmiids.lib;quartz.lib;dmoguids.lib。至此我们获取到了我们需要的设备名称，接下来我们就可以通过ffmpeg.exe解析推流了。