SAPI: Speech to Text example - windows

Question

I am new to SAPI, and I would really appreciate if any of you can provide me a speech to text Hello World example in SAPI. I know MS got some examples like "Dictation" etc, but I would like to start with a very small one. Glad if you can help.

Answer 1

I played a bit with Windows Voice Recognition using SAPI, it really isn't user friendly. Here is an example of code I wrote (in C++) :
#include <sphelper.h>
#include <sapi.h>
#include <iostream>
#include <string>
const ULONGLONG grammarId = 0;
const wchar_t* ruleName1 = L"ruleName1";
int start_listening(const std::string& word);
ISpRecoGrammar* init_grammar(ISpRecoContext* recoContext, const std::string& command);
void get_text(ISpRecoContext* reco_context);
void check_result(const HRESULT& result);
int main(int argc, char** argv)
{
start_listening("Hello");
return EXIT_SUCCESS;
}
// This function exits when the word passed as parameter is said by the user
int start_listening(const std::string& word)
{
// Initialize COM library
if (FAILED(::CoInitialize(nullptr))) {
return EXIT_FAILURE;
}
std::cout << "You should start Windows Recognition" << std::endl;
std::cout << "Just say \""<< word << "\"" << std::endl;
HRESULT hr;
ISpRecognizer* recognizer;
hr = CoCreateInstance(CLSID_SpSharedRecognizer,
nullptr, CLSCTX_ALL, IID_ISpRecognizer,
reinterpret_cast<void**>(&recognizer));
check_result(hr);
ISpRecoContext* recoContext;
hr = recognizer->CreateRecoContext(&recoContext);
check_result(hr);
// Disable context
hr = recoContext->Pause(0);
check_result(hr);
ISpRecoGrammar* recoGrammar = init_grammar(recoContext, word);
hr = recoContext->SetNotifyWin32Event();
check_result(hr);
HANDLE handleEvent;
handleEvent = recoContext->GetNotifyEventHandle();
if(handleEvent == INVALID_HANDLE_VALUE) {
check_result(E_FAIL);
}
ULONGLONG interest;
interest = SPFEI(SPEI_RECOGNITION);
hr = recoContext->SetInterest(interest, interest);
check_result(hr);
// Activate Grammar
hr = recoGrammar->SetRuleState(ruleName1, 0, SPRS_ACTIVE);
check_result(hr);
// Enable context
hr = recoContext->Resume(0);
check_result(hr);
// Wait for reco
HANDLE handles[1];
handles[0] = handleEvent;
WaitForMultipleObjects(1, handles, FALSE, INFINITE);
get_text(recoContext);
std::cout << "Hello user" << std::endl;
recoGrammar->Release();
::CoUninitialize();
system("PAUSE");
return EXIT_SUCCESS;
}
/**
* Create and initialize the Grammar.
* Create a rule for the grammar.
* Add word to the grammar.
*/
ISpRecoGrammar* init_grammar(ISpRecoContext* recoContext, const std::string& command)
{
HRESULT hr;
SPSTATEHANDLE sate;
ISpRecoGrammar* recoGrammar;
hr = recoContext->CreateGrammar(grammarId, &recoGrammar);
check_result(hr);
WORD langId = MAKELANGID(LANG_FRENCH, SUBLANG_FRENCH);
hr = recoGrammar->ResetGrammar(langId);
check_result(hr);
// TODO: Catch error and use default langId => GetUserDefaultUILanguage()
// Create rules
hr = recoGrammar->GetRule(ruleName1, 0, SPRAF_TopLevel | SPRAF_Active, true, &sate);
check_result(hr);
// Add a word
const std::wstring commandWstr = std::wstring(command.begin(), command.end());
hr = recoGrammar->AddWordTransition(sate, NULL, commandWstr.c_str(), L" ", SPWT_LEXICAL, 1, nullptr);
check_result(hr);
// Commit changes
hr = recoGrammar->Commit(0);
check_result(hr);
return recoGrammar;
}
void get_text(ISpRecoContext* reco_context)
{
const ULONG maxEvents = 10;
SPEVENT events[maxEvents];
ULONG eventCount;
HRESULT hr;
hr = reco_context->GetEvents(maxEvents, events, &eventCount);
// Warning hr equal S_FALSE if everything is OK
// but eventCount < requestedEventCount
if(!(hr == S_OK || hr == S_FALSE)) {
check_result(hr);
}
ISpRecoResult* recoResult;
recoResult = reinterpret_cast<ISpRecoResult*>(events[0].lParam);
wchar_t* text;
hr = recoResult->GetText(SP_GETWHOLEPHRASE, SP_GETWHOLEPHRASE, FALSE, &text, NULL);
check_result(hr);
CoTaskMemFree(text);
}
void check_result(const HRESULT& result)
{
if (result == S_OK) {
return;
}
std::string message;
switch(result) {
case E_INVALIDARG:
message = "One or more arguments are invalids.";
case E_ACCESSDENIED:
message = "Acces Denied.";
case E_NOINTERFACE:
message = "Interface does not exist.";
case E_NOTIMPL:
message = "Not implemented method.";
case E_OUTOFMEMORY:
message = "Out of memory.";
case E_POINTER:
message = "Invalid pointer.";
case E_UNEXPECTED:
message = "Unexpecter error.";
case E_FAIL:
message = "Failure";
default:
message = "Unknown : " + std::to_string(result);
}
throw std::exception(message.c_str());
}
As I said, it's a bit complicated. I think you should wrap all that code into a library to make it easier to use.