c++qttext-to-speech

How to use RHVoice via Speech Dispatcher in Qt

I am trying to use RHVoice in my Qt C++ project on a Linux.

I installed RHVoice, and I struggled with its library RHVoice.h, which is provided by librhvoice-dev package, and so far, it seems like a dead end.

Then I found out that Speech-Dispatcher supports RHVoice module, and Qt Text To Speech supports Speech-Dispatcher, so it seemed like the proper way to use RHVoice in Qt.

But the Qt documentation says:

The speech-dispatcher engine does not support any engine specific parameters.

So I cannot make Speech-Dispatcher use RHVoice through Qt, and my question is, basically, how to work around this limitation?

Solution

  • One solution to this is to set RHVoice as the default synthesizer for Speech-Dispatcher, which can be done as follows:

    Modify Speech-Dispatcher configuration by modifying the following files:

    /usr/share/speech-dispatcher/conf/speechd.conf

    /etc/speech-dispatcher/speechd.conf

    If you want to change the configuration per-user only, editing the following file is enough:

    ~/.config/speech-dispatcher/speechd.conf

    Change the DefaultModule to rhvoice as follows:

    ...
# -----OUTPUT MODULES CONFIGURATION-----
...
# The DefaultModule selects which output module is the default.  You
# must use one of the names of the modules loaded with AddModule.

DefaultModule rhvoice

    Save and close, and check if it works in your Qt Project, here's an example:

    CMake:

    cmake_minimum_required(VERSION 3.14)

project(RHVoiceSpeechD LANGUAGES CXX)

set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Core TextToSpeech)
find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Core TextToSpeech)

add_executable(RHVoiceSpeechD
    main.cpp
)
target_link_libraries(RHVoiceSpeechD
    Qt${QT_VERSION_MAJOR}::Core
    Qt${QT_VERSION_MAJOR}::TextToSpeech
)

install(TARGETS RHVoiceSpeechD
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})

    main.cpp:

    #include <QCoreApplication>
#include <QTextToSpeech>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QTextToSpeech tts;

    //set speechd as the engine if it is not the default engine
    tts.setEngine("speechd");

    //test it
    tts.say("I'm using RHVoice as a synthesizer");

    return a.exec();
}

    Run this command in a terminal:

    spd-say -o rhvoice "I'm using RHVoice as a synthesizer"

    and compare the audio output with the one from your Qt project, they should sound the same if the previous steps worked, the default voice for RHVoice is "Alan".

    Sources: