Initial implementation of Flite text-to-speech plug-in

Requires flite headers and libraries (version 2.0.0) installed in
the system.

Change-Id: Iccb5c6b467f76831e8c82d8823c2f2d29ac36d88
Reviewed-by: Jeremy Whiting <jpwhiting@kde.org>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>

11 files changed, 1043 insertions, 0 deletions

diff --git a/config.tests/flite/flite.cpp b/config.tests/flite/flite.cpp
new file mode 100644
index 0000000..d040c0b
--- /dev/null
+++ b/config.tests/flite/flite.cpp
@@ -0,0 +1,55 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Speech module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <flite/flite.h>
+
+static int fliteAudioCb(const cst_wave *w, int start, int size,
+    int last, cst_audio_streaming_info *asi)
+{
+    (void)w;
+    (void)start;
+    (void)size;
+    (void)last;
+    (void)asi;
+    return CST_AUDIO_STREAM_STOP;
+}
+
+int main()
+{
+    cst_audio_streaming_info *asi = new_audio_streaming_info();
+    asi->asc = fliteAudioCb; // This fails for old Flite
+    return 0;
+}
diff --git a/config.tests/flite/flite.pro b/config.tests/flite/flite.pro
new file mode 100644
index 0000000..81e94eb
--- /dev/null
+++ b/config.tests/flite/flite.pro
@@ -0,0 +1,3 @@
+SOURCES = flite.cpp
+
+LIBS += -lflite_cmu_us_kal16 -lflite_usenglish -lflite_cmulex -lflite
diff --git a/qtspeech.pro b/qtspeech.pro
index 7da79db..a5c17fc 100644
--- a/qtspeech.pro
+++ b/qtspeech.pro
@@ -1,2 +1,4 @@
 lessThan(QT_MAJOR_VERSION, 5): error("The QtSpeech library only supports Qt 5.")
+load(configure)
+qtCompileTest(flite)
 load(qt_parts)
diff --git a/src/plugins/tts/flite/flite.pro b/src/plugins/tts/flite/flite.pro
new file mode 100755
index 0000000..f1cdc9b
--- /dev/null
+++ b/src/plugins/tts/flite/flite.pro
@@ -0,0 +1,19 @@
+TARGET = qttexttospeech_flite
+QT = core multimedia texttospeech
+
+PLUGIN_TYPE = texttospeech
+PLUGIN_CLASS_NAME = QTextToSpeechEngineFlite
+load(qt_plugin)
+
+HEADERS += \
+    qtexttospeechengine_flite.h \
+    qtexttospeechplugin_flite.h
+
+SOURCES += \
+    qtexttospeechengine_flite.cpp \
+    qtexttospeechplugin_flite.cpp
+
+OTHER_FILES += \
+    flite_plugin.json
+
+LIBS += -lflite_cmu_us_kal16 -lflite_usenglish -lflite_cmulex -lflite
diff --git a/src/plugins/tts/flite/flite_legal.qdoc b/src/plugins/tts/flite/flite_legal.qdoc
new file mode 100644
index 0000000..f8f4d96
--- /dev/null
+++ b/src/plugins/tts/flite/flite_legal.qdoc
@@ -0,0 +1,217 @@
+/*!
+\page legal-flite.html
+\title Flite Library
+\ingroup licensing
+
+\legalese
+\code
+
+Flite is free software.
+
+We have kept the core code to BSD-like copyright, thus the system is
+free to use in commercial products, with commercial extensions.  GPL
+code is only included as part of the build process and does not
+taint any of the run-time code.
+
+As a collection it is distributed under the following license.  Note
+a few files in this distribution have a different but equally free
+non-conflicting license, see below.
+
+                  Language Technologies Institute
+                     Carnegie Mellon University
+                      Copyright (c) 1999-2014
+                        All Rights Reserved.
+
+  Permission is hereby granted, free of charge, to use and distribute
+  this software and its documentation without restriction, including
+  without limitation the rights to use, copy, modify, merge, publish,
+  distribute, sublicense, and/or sell copies of this work, and to
+  permit persons to whom this work is furnished to do so, subject to
+  the following conditions:
+   1. The code must retain the above copyright notice, this list of
+      conditions and the following disclaimer.
+   2. Any modifications must be clearly marked as such.
+   3. Original authors' names are not deleted.
+   4. The authors' names are not used to endorse or promote products
+      derived from this software without specific prior written
+      permission.
+
+  CARNEGIE MELLON UNIVERSITY AND THE CONTRIBUTORS TO THIS WORK
+  DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
+  ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT
+  SHALL CARNEGIE MELLON UNIVERSITY NOR THE CONTRIBUTORS BE LIABLE
+  FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
+  AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+  ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+  THIS SOFTWARE.
+
+All files within this distribution have the above license except
+the following
+
+src/cg/cst_mlpg.h
+src/cg/cst_mlpg.c
+src/cg/cst_mlsa.h
+src/cg/cst_mlsa.c
+src/cg/cst_vc.h
+src/cg/cst_vc.c
+*********************************************************************
+*                                                                   *
+*            Nagoya Institute of Technology, Aichi, Japan,          *
+*       Nara Institute of Science and Technology, Nara, Japan       *
+*                                and                                *
+*             Carnegie Mellon University, Pittsburgh, PA            *
+*                      Copyright (c) 2003-2004                      *
+*                        All Rights Reserved.                       *
+*                                                                   *
+*  Permission is hereby granted, free of charge, to use and         *
+*  distribute this software and its documentation without           *
+*  restriction, including without limitation the rights to use,     *
+*  copy, modify, merge, publish, distribute, sublicense, and/or     *
+*  sell copies of this work, and to permit persons to whom this     *
+*  work is furnished to do so, subject to the following conditions: *
+*                                                                   *
+*    1. The code must retain the above copyright notice, this list  *
+*       of conditions and the following disclaimer.                 *
+*    2. Any modifications must be clearly marked as such.           *
+*    3. Original authors' names are not deleted.                    *
+*                                                                   *
+*  NAGOYA INSTITUTE OF TECHNOLOGY, NARA INSTITUTE OF SCIENCE AND    *
+*  TECHNOLOGY, CARNEGIE MELLON UNIVERSITY, AND THE CONTRIBUTORS TO  *
+*  THIS WORK DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,  *
+*  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, *
+*  IN NO EVENT SHALL NAGOYA INSTITUTE OF TECHNOLOGY, NARA           *
+*  INSTITUTE OF SCIENCE AND TECHNOLOGY, CARNEGIE MELLON UNIVERSITY, *
+*  NOR THE CONTRIBUTORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR      *
+*  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM   *
+*  LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,  *
+*  NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN        *
+*  CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.         *
+*                                                                   *
+*********************************************************************
+
+These functions are derived from the versions in festvox/src/vc/ as
+modified by Tomoki Toda which in turn contain code derived from
+NITECH's HTS system.  Their copyright has the same freedoms as
+as Flite's but under NAIST, NITECH and/or CMU.
+
+src/audio/au_wince.c
+src/utils/cst_file_stdio.c
+src/utils/cst_mmap_posix.c
+src/utils/cst_mmap_win32.c
+src/utils/cst_mmap_none.c
+src/utils/cst_file_wince.c
+sapi/
+      are copyright Cepstral, LLC rather than CMU but fall under the same
+      free license as the above, except for the owner. (Note the SAPI stuff
+      probably doesn't work any more)
+
+doc/alice
+   Is the first two chapters of Alice in Wonderland as distributed by the
+   Gutenburg project and is now in the public domain
+
+src/regex/regexp.c
+src/regex/regsub.c
+
+ *      Copyright (c) 1986 by University of Toronto.
+ *      Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *      Permission is granted to anyone to use this software for any
+ *      purpose on any computer system, and to redistribute it freely,
+ *      subject to the following restrictions:
+ *
+ *      1. The author is not responsible for the consequences of use of
+ *              this software, no matter how awful, even if they arise
+ *              from defects in it.
+ *
+ *      2. The origin of this software must not be misrepresented, either
+ *              by explicit claim or by omission.
+ *
+ *      3. Altered versions must be plainly marked as such, and must not
+ *              be misrepresented as being the original software.
+
+src/speech/rateconv.c
+
+ *      Copyright (c) 1992, 1995 by Markus Mummert
+ *
+ *      Redistribution and use of this software, modifcation and inclusion
+ *      into other forms of software are permitted provided that the following
+ *      conditions are met:
+ *
+ *      1. Redistributions of this software must retain the above copyright
+ *         notice, this list of conditions and the following disclaimer.
+ *      2. If this software is redistributed in a modified condition
+ *         it must reveal clearly that it has been modified.
+
+lang/usenglish/us_durz_cart.c
+lang/usenglish/us_durz_cart.h
+lang/usenglish/us_int_accent_cart.c
+lang/usenglish/us_int_accent_cart.h
+lang/usenglish/us_int_tone_cart.c
+lang/usenglish/us_int_tone_cart.h
+lang/usenglish/us_phoneset.c
+lang/usenglish/us_f0lr.c
+   These are directly (or indirectly) compiled/derived from files that are
+   part of the Festival Speech Synthesis System (1.4.1).  Hence they have
+   a joint copyright CMU/Edinburgh but with the same free license
+
+configure
+   # Copyright (C) 1992, 93, 94, 95, 96 Free Software Foundation, Inc.
+   #
+   # This configure script is free software; the Free Software Foundation
+   # gives unlimited permission to copy, distribute and modify it.
+
+configure.sub
+config.guess
+missing
+install-sh
+mkinstalldirs
+   Copyright FSF, and under the GPL, these files are only used for
+   convenient configuration and are not part of the generated binary,
+   and therefore do not impose any GPL restrctions on the rest of the
+   system.  But as they are standard methods for configuration they
+   are included.
+
+src/speech/g72x.h
+src/speech/g721.c
+src/speech/g72x.c
+src/speech/g723_24.c
+src/speech/g723_40.c
+
+ *
+ * This source code is a product of Sun Microsystems, Inc. and is provided
+ * for unrestricted use.  Users may copy or modify this source code without
+ * charge.
+ *
+ * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
+ * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
+ *
+ * Sun source code is provided with no support and without any obligation on
+ * the part of Sun Microsystems, Inc. to assist in its use, correction,
+ * modification or enhancement.
+ *
+ * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
+ * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
+ * OR ANY PART THEREOF.
+ *
+ * In no event will Sun Microsystems, Inc. be liable for any lost revenue
+ * or profits or other special, indirect and consequential damages, even if
+ * Sun has been advised of the possibility of such damages.
+ *
+ * Sun Microsystems, Inc.
+ * 2550 Garcia Avenue
+ * Mountain View, California  94043
+ *
+
+lang/cmu_grapheme_lex/grapheme_unitran_tables.c
+ * Copyright 2008-2012, University of Illinois at Urbana-Champaign          *
+ * distributed under the Apache License, Version (2.0)                      *
+ * http://www.apache.org/licenses/LICENSE-2.0                               *
+ * Original table developed by Richard Sproat and Kyoung-young Kim          *
+ * Ported for Festvox by Gopala Anumachipalli gopalakr@cs.cmu.edu Sep 2012  *
+ * Then converted to C for CMU Flite (cmuflite.org)                         *
+
+\endcode
+\endlegalese
+*/
diff --git a/src/plugins/tts/flite/flite_plugin.json b/src/plugins/tts/flite/flite_plugin.json
new file mode 100755
index 0000000..dad4918
--- /dev/null
+++ b/src/plugins/tts/flite/flite_plugin.json
@@ -0,0 +1,6 @@
+{
+    "Keys": ["flite"],
+    "Provider": "flite",
+    "Version": 100,
+    "Features": []
+}
diff --git a/src/plugins/tts/flite/qtexttospeechengine_flite.cpp b/src/plugins/tts/flite/qtexttospeechengine_flite.cpp
new file mode 100755
index 0000000..d49b1bf
--- /dev/null
+++ b/src/plugins/tts/flite/qtexttospeechengine_flite.cpp
@@ -0,0 +1,475 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Speech module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qtexttospeechengine_flite.h"
+
+#include <QGlobalStatic>
+#include <QIODevice>
+#include <QAudioOutput>
+#include <QMutex>
+#include <QDebug>
+#include <QSemaphore>
+#include <QThread>
+
+#include <flite/flite.h>
+
+// en_US voice:
+extern "C" cst_voice *register_cmu_us_kal16();
+extern "C" void unregister_cmu_us_kal16(cst_voice *vox);
+
+QT_BEGIN_NAMESPACE
+
+// Class that handles global Flite initialization and
+// creates the processor thread.
+class FliteLoader
+{
+public:
+    struct FliteVoiceInfo {
+        cst_voice *vox;
+        void (*unregister_func)(cst_voice *vox);
+        QString name;
+        QString localeName;
+        QString gender;
+        QString age;
+    };
+    FliteLoader()
+    {
+        flite_init();
+        FliteVoiceInfo voice_enus = { register_cmu_us_kal16(), unregister_cmu_us_kal16, "kal16", "en_US", "male", "adult" };
+        if (voice_enus.vox)
+            m_voices.append(voice_enus);
+        m_processor = new FliteProcessor();
+        QObject::connect(m_processor, &QThread::finished, &QThread::deleteLater);
+        m_processor->start();
+    }
+    ~FliteLoader()
+    {
+        foreach (const FliteLoader::FliteVoiceInfo &voice, m_voices)
+            voice.unregister_func(voice.vox);
+        m_processor->exit();
+    }
+    const QVector<FliteVoiceInfo> &voices() const
+    {
+        return m_voices;
+    }
+    FliteProcessor *processor() const
+    {
+        return m_processor;
+    }
+private:
+    QVector<FliteVoiceInfo> m_voices;
+    FliteProcessor *m_processor;
+};
+
+Q_GLOBAL_STATIC(FliteLoader, fliteLoader)
+
+FliteProcessor::FliteProcessor():
+    m_stop(true),
+    m_idle(true),
+    m_rate(0),
+    m_pitch(0),
+    m_volume(100)
+{
+}
+
+FliteProcessor::~FliteProcessor()
+{
+}
+
+void FliteProcessor::say(cst_voice *voice, const QString &text)
+{
+    if (isInterruptionRequested())
+        return;
+    QMutexLocker lock(&m_lock);
+    m_stop = true; // Cancel any previous utterance
+    m_idle = false;
+    m_nextText = text;
+    m_nextVoice = voice;
+    setRateForVoice(m_nextVoice, m_rate);
+    setPitchForVoice(m_nextVoice, m_pitch);
+    m_speakSem.release();
+}
+
+void FliteProcessor::stop()
+{
+    QMutexLocker lock(&m_lock);
+    m_stop = true;
+    m_nextText.clear();
+    m_nextVoice = 0;
+    m_speakSem.release();
+}
+
+bool FliteProcessor::setRate(float rate)
+{
+    QMutexLocker lock(&m_lock);
+    if (rate >= -1.0 && rate <= 1.0) {
+        m_rate = rate;
+        return true;
+    }
+    return false;
+}
+
+bool FliteProcessor::setPitch(float pitch)
+{
+    QMutexLocker lock(&m_lock);
+    if (pitch >= -1.0 && pitch <= 1.0) {
+        m_pitch = pitch;
+        return true;
+    }
+    return false;
+}
+
+bool FliteProcessor::setVolume(int volume)
+{
+    QMutexLocker lock(&m_lock);
+    if (volume >= 0 && volume <= 100) {
+        m_volume = volume;
+        if (m_audio)
+            m_audio->setVolume(((qreal)m_volume) / 100.0);
+        return true;
+    }
+    return false;
+}
+
+void FliteProcessor::exit()
+{
+    QThread::exit();
+    requestInterruption();
+    stop();
+}
+
+bool FliteProcessor::isIdle()
+{
+    QMutexLocker lock(&m_lock);
+    return m_idle;
+}
+
+float FliteProcessor::rate()
+{
+    QMutexLocker lock(&m_lock);
+    return m_rate;
+}
+
+float FliteProcessor::pitch()
+{
+    QMutexLocker lock(&m_lock);
+    return m_pitch;
+}
+
+int FliteProcessor::volume()
+{
+    QMutexLocker lock(&m_lock);
+    return m_volume;
+}
+
+void FliteProcessor::run()
+{
+    forever {
+        m_lock.lock();
+        if (!m_speakSem.tryAcquire()) {
+            m_idle = true;
+            m_lock.unlock();
+            emit notSpeaking(); // Going idle
+            m_speakSem.acquire();
+            m_lock.lock();
+        }
+        if (isInterruptionRequested()) {
+            m_lock.unlock();
+            return;
+        }
+        m_stop = false;
+        if (!m_nextText.isEmpty() && m_nextVoice) {
+            cst_audio_streaming_info *asi;
+            QString text = m_nextText;
+            cst_voice *voice = m_nextVoice;
+            m_nextText.clear();
+            m_nextVoice = 0;
+            m_lock.unlock();
+            asi = new_audio_streaming_info();
+            asi->asc = FliteProcessor::fliteAudioCb;
+            asi->userdata = (void *)this;
+            feat_set(voice->features, "streaming_info", audio_streaming_info_val(asi));
+            flite_text_to_speech(text.toUtf8().constData(), voice, "none");
+        } else {
+            m_lock.unlock();
+        }
+    }
+}
+
+void FliteProcessor::setRateForVoice(cst_voice *voice, float rate)
+{
+    float stretch = 1.0;
+    Q_ASSERT(rate >= -1.0 && rate <= 1.0);
+    // Stretch multipliers taken from Speech Dispatcher
+    if (rate < 0)
+        stretch -= rate * 2;
+    if (rate > 0)
+        stretch -= rate * (100.0 / 175.0);
+    feat_set_float(voice->features, "duration_stretch", stretch);
+}
+
+void FliteProcessor::setPitchForVoice(cst_voice *voice, float pitch)
+{
+    float f0;
+    Q_ASSERT(pitch >= -1.0 && pitch <= 1.0);
+    // Conversion taken from Speech Dispatcher
+    f0 = (pitch * 80) + 100;
+    feat_set_float(voice->features, "int_f0_target_mean", f0);
+}
+
+int FliteProcessor::audioOutput(const cst_wave *w, int start, int size,
+                int last, cst_audio_streaming_info *asi)
+{
+    Q_UNUSED(asi);
+    int ret = CST_AUDIO_STREAM_CONT;
+    if (start == 0) {
+        m_lock.lock();
+        QAudioFormat format;
+        format.setSampleRate(w->sample_rate);
+        format.setChannelCount(w->num_channels);
+        format.setSampleSize(16);
+        format.setSampleType(QAudioFormat::SignedInt);
+        format.setCodec("audio/pcm");
+        m_audio = new QAudioOutput(format);
+        m_audio->setVolume(((qreal)m_volume) / 100.0);
+        m_audioBuffer = m_audio->start();
+        m_lock.unlock();
+    }
+    int bytesToWrite = size * sizeof(short);
+    int bytesWritten = 0;
+    forever {
+        m_lock.lock();
+        if (m_stop || !m_audioBuffer
+        || m_audio->state() == QAudio::StoppedState || isInterruptionRequested()) {
+            m_lock.unlock();
+            ret = CST_AUDIO_STREAM_STOP;
+            break;
+        }
+        bytesWritten += m_audioBuffer->write((const char*)(&w->samples[start + bytesWritten/sizeof(short)]), bytesToWrite - bytesWritten);
+        m_lock.unlock();
+        if (bytesWritten >= bytesToWrite)
+            break;
+        QThread::msleep(200);
+    }
+    m_lock.lock();
+    if (m_stop || last == 1) {
+        if (m_stop) {
+            m_audio->reset(); // Discard buffered audio
+        } else {
+            // TODO: Find a way to reliably check if all the audio has been written out before stopping
+            m_audioBuffer->write(QByteArray(1024, 0));
+            QThread::msleep(200);
+            m_audio->stop();
+        }
+        delete m_audio;
+        m_audio = 0;
+        m_audioBuffer = 0;
+    }
+    m_lock.unlock();
+    return ret;
+}
+
+int FliteProcessor::fliteAudioCb(const cst_wave *w, int start, int size,
+    int last, cst_audio_streaming_info *asi)
+{
+    FliteProcessor *processor = static_cast<FliteProcessor *>(asi->userdata);
+    if (processor)
+        return processor->audioOutput(w, start, size, last, asi);
+    return CST_AUDIO_STREAM_STOP;
+}
+
+QTextToSpeechEngineFlite::QTextToSpeechEngineFlite(
+    const QVariantMap &parameters, QObject *parent) :
+        QTextToSpeechEngine(parent),
+        m_state(QTextToSpeech::Ready)
+{
+    Q_UNUSED(parameters);
+}
+
+QTextToSpeechEngineFlite::~QTextToSpeechEngineFlite()
+{
+
+}
+
+QVector<QLocale> QTextToSpeechEngineFlite::availableLocales() const
+{
+    return m_locales;
+}
+
+QVector<QVoice> QTextToSpeechEngineFlite::availableVoices() const
+{
+    return m_voices.values(m_currentLocale.name()).toVector();
+}
+
+void QTextToSpeechEngineFlite::say(const QString &text)
+{
+    int id = QTextToSpeechEngine::voiceData(m_currentVoice).toInt();
+    cst_voice *voiceData = fliteLoader()->voices()[id].vox;
+    m_state = QTextToSpeech::Speaking;
+    emit stateChanged(m_state);
+    fliteLoader()->processor()->say(voiceData, text);
+}
+
+void QTextToSpeechEngineFlite::stop()
+{
+    fliteLoader()->processor()->stop();
+    m_state = QTextToSpeech::Ready;
+    emit stateChanged(m_state);
+}
+
+void QTextToSpeechEngineFlite::pause()
+{
+    // Not supported, just stop:
+    stop();
+}
+
+void QTextToSpeechEngineFlite::resume()
+{
+
+}
+
+double QTextToSpeechEngineFlite::rate() const
+{
+    return fliteLoader()->processor()->rate();
+}
+
+bool QTextToSpeechEngineFlite::setRate(double rate)
+{
+    return fliteLoader()->processor()->setRate(rate);
+}
+
+double QTextToSpeechEngineFlite::pitch() const
+{
+    return fliteLoader()->processor()->pitch();
+}
+
+bool QTextToSpeechEngineFlite::setPitch(double pitch)
+{
+    return fliteLoader()->processor()->setPitch(pitch);
+}
+
+QLocale QTextToSpeechEngineFlite::locale() const
+{
+    return m_currentLocale;
+}
+
+bool QTextToSpeechEngineFlite::setLocale(const QLocale &locale)
+{
+    bool localeFound = false;
+    foreach (const QLocale &l, m_locales) {
+        if (l.name() == locale.name()) {
+            localeFound = true;
+            break;
+        }
+    }
+    if (!localeFound)
+        return false;
+    if (m_currentLocale.name() != locale.name()) {
+        m_currentLocale = locale;
+        m_currentVoice = availableVoices().at(0);
+    }
+    return true;
+}
+
+int QTextToSpeechEngineFlite::volume() const
+{
+    return fliteLoader()->processor()->volume();
+}
+
+bool QTextToSpeechEngineFlite::setVolume(int volume)
+{
+    return fliteLoader()->processor()->setVolume(volume);
+}
+
+QVoice QTextToSpeechEngineFlite::voice() const
+{
+    return m_currentVoice;
+}
+
+bool QTextToSpeechEngineFlite::setVoice(const QVoice &voice)
+{
+    foreach (const QVoice &availableVoice, availableVoices()) {
+        if (QTextToSpeechEngine::voiceData(availableVoice) == QTextToSpeechEngine::voiceData(voice)) {
+            m_currentVoice = voice;
+            return true;
+        }
+    }
+    return false;
+}
+
+QTextToSpeech::State QTextToSpeechEngineFlite::state() const
+{
+    return m_state;
+}
+
+bool QTextToSpeechEngineFlite::init(QString *errorString)
+{
+    int i = 0;
+    QVector<FliteLoader::FliteVoiceInfo> voices = fliteLoader()->voices();
+    foreach (const FliteLoader::FliteVoiceInfo &fliteVoice, voices) {
+        QVoice::Age age = QVoice::Other;
+        QVoice::Gender gender = QVoice::Unknown;
+        QString name = fliteVoice.name;
+        QLocale locale(fliteVoice.localeName);
+        QVoice voice = QTextToSpeechEngine::createVoice(name, gender, age, QVariant(i));
+        m_voices.insert(fliteVoice.localeName, voice);
+        if (!m_locales.contains(locale))
+            m_locales.append(locale);
+        // Use the first available locale/voice as a fallback
+        if (i == 0) {
+            m_currentVoice = voice;
+            m_currentLocale = locale;
+        }
+        i++;
+    }
+    // Attempt to switch to the system locale
+    setLocale(QLocale::system());
+    connect(fliteLoader()->processor(), &FliteProcessor::notSpeaking,
+            this, &QTextToSpeechEngineFlite::onNotSpeaking);
+    if (errorString)
+        *errorString = QStringLiteral("");
+    return true;
+}
+
+void QTextToSpeechEngineFlite::onNotSpeaking()
+{
+    if (m_state != QTextToSpeech::Ready && fliteLoader()->processor()->isIdle()) {
+        m_state = QTextToSpeech::Ready;
+        emit stateChanged(m_state);
+    }
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/tts/flite/qtexttospeechengine_flite.h b/src/plugins/tts/flite/qtexttospeechengine_flite.h
new file mode 100755
index 0000000..ff94bef
--- /dev/null
+++ b/src/plugins/tts/flite/qtexttospeechengine_flite.h
@@ -0,0 +1,141 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Speech module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QTEXTTOSPEECHENGINE_FLITE_H
+#define QTEXTTOSPEECHENGINE_FLITE_H
+
+#include "qtexttospeechengine.h"
+#include "qvoice.h"
+
+#include <QtCore/QString>
+#include <QtCore/QLocale>
+#include <QtCore/QVector>
+#include <QtCore/QThread>
+#include <QtCore/QMutex>
+#include <QtCore/QSemaphore>
+#include <QtCore/QIODevice>
+#include <QtMultimedia/QAudioOutput>
+
+#include <flite/flite.h>
+
+QT_BEGIN_NAMESPACE
+
+class FliteProcessor : public QThread {
+    Q_OBJECT
+
+public:
+    FliteProcessor();
+    ~FliteProcessor();
+    void say(cst_voice *voice, const QString &text);
+    void stop();
+    bool setRate(float rate);
+    bool setPitch(float pitch);
+    bool setVolume(int volume);
+    void exit();
+    bool isIdle();
+    float rate();
+    float pitch();
+    int volume();
+
+signals:
+    void notSpeaking();
+
+private:
+    QMutex m_lock;
+    bool m_stop;
+    bool m_idle;
+    float m_rate;
+    float m_pitch;
+    int m_volume;
+    QSemaphore m_speakSem;
+    QString m_nextText;
+    cst_voice *m_nextVoice;
+    QAudioOutput *m_audio;
+    QIODevice *m_audioBuffer;
+    void run();
+    void setRateForVoice(cst_voice *voice, float rate);
+    void setPitchForVoice(cst_voice *voice, float pitch);
+    int audioOutput(const cst_wave *w, int start, int size,
+                    int last, cst_audio_streaming_info *asi);
+    static int fliteAudioCb(const cst_wave *w, int start, int size,
+                            int last, cst_audio_streaming_info *asi);
+};
+
+class QTextToSpeechEngineFlite : public QTextToSpeechEngine
+{
+    Q_OBJECT
+
+public:
+    QTextToSpeechEngineFlite(const QVariantMap &parameters, QObject *parent);
+    virtual ~QTextToSpeechEngineFlite();
+
+    // Plug-in API:
+    QVector<QLocale> availableLocales() const Q_DECL_OVERRIDE;
+    QVector<QVoice> availableVoices() const Q_DECL_OVERRIDE;
+    void say(const QString &text) Q_DECL_OVERRIDE;
+    void stop() Q_DECL_OVERRIDE;
+    void pause() Q_DECL_OVERRIDE;
+    void resume() Q_DECL_OVERRIDE;
+    double rate() const Q_DECL_OVERRIDE;
+    bool setRate(double rate) Q_DECL_OVERRIDE;
+    double pitch() const Q_DECL_OVERRIDE;
+    bool setPitch(double pitch) Q_DECL_OVERRIDE;
+    QLocale locale() const Q_DECL_OVERRIDE;
+    bool setLocale(const QLocale &locale) Q_DECL_OVERRIDE;
+    int volume() const Q_DECL_OVERRIDE;
+    bool setVolume(int volume) Q_DECL_OVERRIDE;
+    QVoice voice() const Q_DECL_OVERRIDE;
+    bool setVoice(const QVoice &voice) Q_DECL_OVERRIDE;
+    QTextToSpeech::State state() const Q_DECL_OVERRIDE;
+
+    // Internal API:
+    bool init(QString *errorString);
+
+public slots:
+    void onNotSpeaking();
+
+private:
+    QTextToSpeech::State m_state;
+    QLocale m_currentLocale;
+    QVector<QLocale> m_locales;
+    QVoice m_currentVoice;
+    // Voices mapped by their locale name.
+    QMultiMap<QString, QVoice> m_voices;
+};
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/plugins/tts/flite/qtexttospeechplugin_flite.cpp b/src/plugins/tts/flite/qtexttospeechplugin_flite.cpp
new file mode 100755
index 0000000..783012b
--- /dev/null
+++ b/src/plugins/tts/flite/qtexttospeechplugin_flite.cpp
@@ -0,0 +1,55 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Speech module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qtexttospeechplugin_flite.h"
+#include "qtexttospeechengine_flite.h"
+
+QT_BEGIN_NAMESPACE
+
+Q_LOGGING_CATEGORY(lcSpeechTtsFlite, "qt.speech.tts.flite")
+
+QTextToSpeechEngine *QTextToSpeechPluginFlite::createTextToSpeechEngine(
+        const QVariantMap &parameters, QObject *parent, QString *errorString) const
+{
+    QTextToSpeechEngineFlite *flite = new QTextToSpeechEngineFlite(parameters, parent);
+    if (flite && flite->init(errorString)) {
+        return flite;
+    }
+    delete flite;
+    return 0;
+}
+
+QT_END_NAMESPACE
diff --git a/src/plugins/tts/flite/qtexttospeechplugin_flite.h b/src/plugins/tts/flite/qtexttospeechplugin_flite.h
new file mode 100755
index 0000000..fe9ed64
--- /dev/null
+++ b/src/plugins/tts/flite/qtexttospeechplugin_flite.h
@@ -0,0 +1,66 @@
+/****************************************************************************
+**
+** Copyright (C) 2015 The Qt Company Ltd.
+** Contact: http://www.qt.io/licensing/
+**
+** This file is part of the Qt Speech module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL3$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see http://www.qt.io/terms-conditions. For further
+** information use the contact form at http://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPLv3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or later as published by the Free
+** Software Foundation and appearing in the file LICENSE.GPL included in
+** the packaging of this file. Please review the following information to
+** ensure the GNU General Public License version 2.0 requirements will be
+** met: http://www.gnu.org/licenses/gpl-2.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QTEXTTOSPEECHPLUGIN_FLITE_H
+#define QTEXTTOSPEECHPLUGIN_FLITE_H
+
+#include "qtexttospeechplugin.h"
+#include "qtexttospeechengine.h"
+
+#include <QtCore/QObject>
+#include <QtCore/QLoggingCategory>
+
+QT_BEGIN_NAMESPACE
+
+Q_DECLARE_LOGGING_CATEGORY(lcSpeechTtsFlite)
+
+class QTextToSpeechPluginFlite : public QObject, public QTextToSpeechPlugin
+{
+    Q_OBJECT
+    Q_INTERFACES(QTextToSpeechPlugin)
+    Q_PLUGIN_METADATA(IID "org.qt-project.qt.speech.tts.plugin/5.0"
+                      FILE "flite_plugin.json")
+
+public:
+    QTextToSpeechEngine *createTextToSpeechEngine(
+                                const QVariantMap &parameters,
+                                QObject *parent,
+                                QString *errorString) const;
+};
+
+QT_END_NAMESPACE
+
+#endif
diff --git a/src/plugins/tts/tts.pro b/src/plugins/tts/tts.pro
index ef07835..fd333c0 100755
--- a/src/plugins/tts/tts.pro
+++ b/src/plugins/tts/tts.pro
@@ -6,3 +6,7 @@ unix {
         SUBDIRS += speechdispatcher
     }
 }
+
+config_flite {
+    SUBDIRS += flite
+}