SAPI: Speech to Text example

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.