How to use IRDPSRAPIAudiostream in C++?

Luis Claudio 6

I´m writing a Windows desktop application in C++ for sharing desktop screen with some viewers, using IRDPSRAPI.
I can share the desktop screen, but not the sound. For example, if I play a video in the sharer´s computer, the viewers can see the video, but can´t hear its sound, so I´m trying to use IRDPSRAPIAudiostream for sharing the audio as well. Is this the right way to do it?
I´ve read the API documentation (https://learn.microsoft.com/en-us/windows/win32/api/rdpencomapi/nn-rdpencomapi-irdpsrapiaudiostream), but it´s too vague, and I couldn´t find any code sample on internet.
If I have a sharing session and an attendee, how do I create a audio stream? I tried using QueryInterface to get IRDSRAPIAudiostream both from the sharing session and from the attendee, but none of them suceeded.
Can anybody give me some hint?

Thanks a lot.

Junjie Zhu - MSFT 17,826 Reputation points Microsoft Vendor

2022-02-15T05:53:14.037+00:00

Could you provide the code? Does not contain any personal privacy.

Luis Claudio 6

As I don´t know the right way to get the IRDPSRAPIAudiostream interface, I tried to qet it from the session (immediately after creating the session, in procedure share_screen below) and from the IRDPSRAPIAttendee as soon as a new viewer connected (the procedure viewerConnected bellow is invoked when a new viewer is connected to the sharer).
I know that in the final version the audioStream will be got only in one point (may one of these two). Currently I´m trying to get it in both points just to find out where it can be gotten, and it´s failing in both points.
void share_screen() {
if (share_session == NULL) {

                HRESULT hr = CoCreateInstance(__uuidof(RDPSession),
                    NULL, CLSCTX_ALL,
                    __uuidof(IRDPSRAPISharingSession),
                    reinterpret_cast<void**>(&share_session));

                if (SUCCEEDED(hr)) {

                    IUnknown* unknown_ptr = reinterpret_cast<IUnknown*>(share_session);
                    IUnknown* eventWatcher = reinterpret_cast<IUnknown*>(&ev);
                    IConnectionPointContainer** l_conn_point_container = &conn_point_container;
                    IConnectionPoint** l_conn_point = &conn_point;

                    unsigned long cookie = 0;
                    IConnectionPointContainer* conn_point_container = 0;
                    IConnectionPoint* conn_point = 0;
                    *l_conn_point_container = 0;
                    *l_conn_point = 0;

                    hr = unknown_ptr->QueryInterface(IID_IConnectionPointContainer, (void**)&conn_point_container);
                    if (SUCCEEDED(hr))
                    {
                        *l_conn_point_container = conn_point_container;
                        hr = conn_point_container->FindConnectionPoint(__uuidof(_IRDPSessionEvents), &conn_point);
                        if (SUCCEEDED(hr))
                        {
                            *l_conn_point = conn_point;
                            hr = conn_point->Advise(eventWatcher, &cookie);

                        }
                    }

                    if (share_session->Open() == S_OK) {
                        if (share_session->get_Invitations(&invitationMgr) == S_OK) {
                            if (GenerateInvitation())
                            {
                                if (audioStream == NULL)
                                {
                                    hr = share_session->QueryInterface(__uuidof(IRDPSRAPIAudioStream), (void**)&audioStream);
                                    if (SUCCEEDED(hr))
                                    {
                                        OutputDebugString("audioStream OK\n");
                                        audioStream->AddRef();
                                    }
                                    else
                                    {
                                        OutputDebugString("Failed to obtain audioStream from Session\n");
                                        audioStream = NULL;
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }



        void ViewerConnected(IDispatch* pViewer) {
            IRDPSRAPIAttendee* pRDPViewer;
            pViewer->QueryInterface(__uuidof(IRDPSRAPIAttendee), (void**)&pRDPViewer);
            pRDPViewer->put_ControlLevel(CTRL_LEVEL::CTRL_LEVEL_VIEW);
            std::string outputString;
            HRESULT hr;
            if (audioStream == NULL)
            {
                hr = pViewer->QueryInterface(__uuidof(IRDPSRAPIAudioStream), (void**)&audioStream);
                if (SUCCEEDED(hr))
                {
                    OutputDebugString("Got audioStream from pViewer\n");
                    __int64 audioPeriod;
                    bool audioOk = false;
                    audioStream->AddRef();
                    hr = audioStream->Initialize(&audioPeriod);
                    if (SUCCEEDED(hr))
                    {
                        outputString = "audioStream started with period=" + std::to_string(audioPeriod) + "\n";
                        OutputDebugString(outputString.c_str());
                        hr = audioStream->Start();
                        if (SUCCEEDED(hr))
                        {
                            OutputDebugString("audioStream started OK\n");
                            audioOk = true;
                        }
                        else
                        {
                            OutputDebugString("Failed to start audioStream\n");
                        }
                    }
                    else
                    {
                        OutputDebugString("Failed to initialize audioStream\n");
                    }
                    if (!audioOk)
                    {
                        audioStream->Release();
                        audioStream = NULL;
                    }
                }
                else
                {
                    outputString = "Failed to get audioStream from Viewer: " + std::to_string(hr) + "\n";
                    OutputDebugString(outputString.c_str());
                    audioStream = NULL;
                }

            }
         }

Junjie Zhu - MSFT 17,826 Reputation points Microsoft Vendor

2022-02-16T06:28:20.073+00:00

Could you provide the debug log？
Luis Claudio 6 Reputation points

2022-02-16T14:25:30.31+00:00

These are the logs I got related to audioStream:
When the sharing session is started (procedure share_screen):
.
.
.
O thread 0xc98 foi fechado com o código 0 (0x0).
Failed to obtain audioStream from Session
"ServidorRDPJanela.exe" (Win32): Carregado "C:\Windows\SysWOW64\fdProxy.dll". Símbolos carregados.
.
.
.

When a viewer connected (procedure ViewerConnected):
Server tratando evento 301
Failed to get audioStream from Viewer: -2147467262
"ServidorRDPJanela.exe" (Win32): Não carregado "C:\Windows\SysWOW64\igdusc32.dll"
Junjie Zhu - MSFT 17,826 Reputation points Microsoft Vendor

2022-02-21T06:31:33.51+00:00

I would like to reproduce your problem on my computer, but I don't know how your session is initialized, can you share the Minimal, Reproducible Example ?
Luis Claudio 6 Reputation points

2022-02-22T18:15:46.91+00:00

I uploaded the code to gitHub.
Please get the code from RDP
Junjie Zhu - MSFT 17,826 Reputation points Microsoft Vendor

2022-02-23T10:10:36.2+00:00

I can successfully run your server-side code, HRESULT is E_NOINTERFACE No such interface supported, this problem is unexpected, I will contact the team, need to wait for a period of time.
Luis Claudio 6 Reputation points

2022-02-23T11:44:55.187+00:00

Thank you.
I appreciate your atention.
Luis Claudio 6 Reputation points

2022-05-03T18:56:05.96+00:00

Hi JunjieZhu

Have you been able to contact your team about this issue?
Junjie Zhu - MSFT 17,826 Reputation points Microsoft Vendor

2022-05-04T01:31:27.243+00:00

I've raised this issue with the team through internal channels, we are still discussing it and analyzing the ttd trace,, I'll update if there is any news.

1 answer

Junjie Zhu - MSFT 17,826 Reputation points Microsoft Vendor

2023-04-25T07:06:10.31+00:00

Hello @Luis Claudio

Sorry for the delay. I searched the official documentation and code samples, but I didn't see any examples of actually successfully obtaining IRDPSRAPIAudioStream. But here is the description of WDS and Desktop Duplication API in the documentation.

Beginning with Windows 8 and Windows Server 2012, Windows Desktop Sharing uses the Desktop Duplication API. To ensure that your application will work correctly at all dots per inch (dpi) settings, your application must be DPI-aware. The recommended method for doing this is to configure the application manifest to mark your application as per-monitor DPI-aware as described in Writing DPI-Aware Desktop and Win32 Applications. This will set the application level when the application is launched.

It is recommended to use the Desktop Duplication API to achieve this function first.

Thank you,

Junjie
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