Microsoft Speech Platform

Use TTS Events

The Microsoft Speech Platform includes events that provide notifications and return information about the status of text-to-speech (TTS) operations. Most TTS events are raised by the TTS engine while it is generating synthesized speech. An application can register to receive notification of the events that it wants to process. In addition to subscribing to events, applications should establish a Win32 event to signal when speech events are available.

Example

The following code excerpt subscribes to events that are raised when speech synthesis begins and when the input stream ends, and establishes a Win32 event.

`

// Subscribe to the end stream event and the bookmark event.
if (SUCCEEDED(hr))
{
ULONGLONG ullEventInterest = SPFEI(SPEI_END_INPUT_STREAM) | SPFEI(SPEI_TTS_BOOKMARK);
hr = cpVoice->SetInterest(ullEventInterest, ullEventInterest);
}

// Establish a Win32 event to signal when speech events are available.
HANDLE hSpeechNotifyEvent = INVALID_HANDLE_VALUE;
if (SUCCEEDED(hr))
{
hr = cpVoice->SetNotifyWin32Event();
}
if (SUCCEEDED(hr))
{
hSpeechNotifyEvent = cpContext->GetNotifyEventHandle();
if (INVALID_HANDLE_VALUE == hSpeechNotifyEvent)
{
// Notification handle unsupported.
hr = E_NOINTERFACE;
}
}

See the end of this topic for an example of a complete console application that subscribes to events, generates speech, and processes events raised during speech generation.

TTS events in the Speech Platform

The following table lists and describes the events raised in the Speech Platform to support speech synthesis (TTS).

Complete TTS example

The following is an example of a complete console application that subscribes to events, generates speech, and processes events raised during speech generation.

`

int _tmain(int argc, _TCHAR* argv[])
{
CoInitialize(NULL);
{
HRESULT hr = S_OK;

    // Find the best token to use for a voice that speaks US English, preferably female.
    CComPtr<ISpObjectToken> cpVoiceToken;

    if (SUCCEEDED(hr))
    {
        hr = SpFindBestToken(SPCAT_VOICES, L"language=409", L"gender=female", &cpVoiceToken;);
    }

    // Create a voice and set its token to the one we just found.
    CComPtr<ISpVoice> cpVoice;

    if (SUCCEEDED(hr))
    {
        hr = cpVoice.CoCreateInstance(CLSID_SpVoice);
    }

    if (SUCCEEDED(hr))
    {
        hr = cpVoice->SetVoice(cpVoiceToken);
    }

    // Register interest in the END_INPUT_STREAM and TTS_BOOKMARK events.
    if (SUCCEEDED(hr))
    {
        ULONGLONG ullEventInterest = SPFEI(SPEI_END_INPUT_STREAM) | SPFEI(SPEI_TTS_BOOKMARK);
        hr = cpVoice->SetInterest(ullEventInterest, ullEventInterest);
    }

    // Get the notification event handle so we can wait until we are signaled with events.
    HANDLE hSpeechNotifyEvent = NULL;

    if (SUCCEEDED(hr))
    {
        hSpeechNotifyEvent = cpVoice->GetNotifyEventHandle();

        if (INVALID_HANDLE_VALUE == hSpeechNotifyEvent)
        {
            // Notification handle unsupported by engine.
            hr = E_NOINTERFACE;
        }
    }

    // Establish a separate win32 event to signal event loop exit.
    HANDLE hExitEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

    // Collect the events listened for to pump the speech event loop.
    HANDLE rghEvents[] = { hSpeechNotifyEvent, hExitEvent };

    // Speak an SSML prompt from a file, asynchronously, so we can wait for events.
    if (SUCCEEDED(hr))
    {
		hr = cpVoice->Speak(L"C:\\Test.ssxml", SPF_IS_FILENAME | SPF_IS_XML | SPF_PARSE_SSML | SPF_ASYNC, 0);
    }        

    // Speech synthesis event loop; continue until the exit event is signaled.
    BOOL fContinue = TRUE;

    while (fContinue && SUCCEEDED(hr))
    {
        // Wait for either a speech event or an exit event.
        DWORD dwMessage = WaitForMultipleObjects(sp_countof(rghEvents), rghEvents, FALSE, INFINITE);

        switch (dwMessage)
        {
            // With the WaitForMultipleObjects call above, WAIT_OBJECT_0 is a speech event from hSpeechNotifyEvent.
            case WAIT_OBJECT_0: 
            {
                // Sequentially grab all available speech events from the speech event queue.
                CSpEvent spevent;
                while (S_OK == spevent.GetFrom(cpVoice))
                {
                    switch (spevent.eEventId)
                    {
                        case SPEI_END_INPUT_STREAM:
                            // The TTS stream has completed; we should exit the loop.
                            SetEvent(hExitEvent);
                            break;
                        case SPEI_TTS_BOOKMARK:
                            // We just received a bookmark event; print the name of the bookmark reached.
                            LPCWSTR pszBookmarkName = spevent.BookmarkName();
                            wprintf(L"Bookmark reached: %s\r\n", pszBookmarkName);
                            break;
                    }
                }

                break;
            }
            case WAIT_OBJECT_0 + 1:
            {
                // Exit event; discontinue the speech loop.
                fContinue = FALSE;
                break;
            }
        }
    }
}
CoUninitialize();

return 0;

}

The contents of the SSML document (Test.ssxml) referenced in the code example are as follows:

`

<?xml version="1.0" encoding="ISO-8859-1"?>
<speak version="1.0"
xmlns="http://www.w3.org/2001/10/synthesis"
xml:lang="en-US">

<s> Now for today's weather. </s>
</speak>