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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** 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 https://www.qt.io/terms-conditions. For further
** information use the contact form at https://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.LGPL3 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-3.0.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 (at your option) the GNU General
** Public license version 3 or any later version approved by the KDE Free
** Qt Foundation. The licenses are as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-2.0.html and
** https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <qaudio.h>
#include <qmath.h>
#include <QDebug>
QT_BEGIN_NAMESPACE
#define LOG100 4.60517018599
static void qRegisterAudioMetaTypes()
{
qRegisterMetaType<QAudio::Error>();
qRegisterMetaType<QAudio::State>();
qRegisterMetaType<QAudio::Mode>();
qRegisterMetaType<QAudio::Role>();
qRegisterMetaType<QAudio::VolumeScale>();
}
Q_CONSTRUCTOR_FUNCTION(qRegisterAudioMetaTypes)
/*!
\namespace QAudio
\ingroup multimedia-namespaces
\brief The QAudio namespace contains enums used by the audio classes.
\inmodule QtMultimedia
\ingroup multimedia
\ingroup multimedia_audio
*/
/*!
\enum QAudio::Error
\value NoError No errors have occurred
\value OpenError An error occurred opening the audio device
\value IOError An error occurred during read/write of audio device
\value UnderrunError Audio data is not being fed to the audio device at a fast enough rate
\value FatalError A non-recoverable error has occurred, the audio device is not usable at this time.
*/
/*!
\enum QAudio::State
\value ActiveState Audio data is being processed, this state is set after start() is called
and while audio data is available to be processed.
\value SuspendedState The audio device is in a suspended state, this state will only be entered
after suspend() is called.
\value StoppedState The audio device is closed, and is not processing any audio data
\value IdleState The QIODevice passed in has no data and audio system's buffer is empty, this state
is set after start() is called and while no audio data is available to be processed.
*/
/*!
\enum QAudio::Mode
\value AudioOutput audio output device
\value AudioInput audio input device
*/
/*!
\enum QAudio::Role
This enum describes the role of an audio stream.
\value UnknownRole The role is unknown or undefined
\value MusicRole Music
\value VideoRole Soundtrack from a movie or a video
\value VoiceCommunicationRole Voice communications, such as telephony
\value AlarmRole Alarm
\value NotificationRole Notification, such as an incoming e-mail or a chat request
\value RingtoneRole Ringtone
\value AccessibilityRole For accessibility, such as with a screen reader
\value SonificationRole Sonification, such as with user interface sounds
\value GameRole Game audio
\since 5.6
\sa QMediaPlayer::setAudioRole()
*/
/*!
\enum QAudio::VolumeScale
This enum defines the different audio volume scales.
\value LinearVolumeScale Linear scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
volume. All Qt Multimedia classes that have an audio volume use
a linear scale.
\value CubicVolumeScale Cubic scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is full
volume.
\value LogarithmicVolumeScale Logarithmic Scale. \c 0.0 (0%) is silence and \c 1.0 (100%) is
full volume. UI volume controls should usually use a logarithmic
scale.
\value DecibelVolumeScale Decibel (dB, amplitude) logarithmic scale. \c -200 is silence
and \c 0 is full volume.
\since 5.8
\sa QAudio::convertVolume()
*/
namespace QAudio
{
/*!
\fn qreal QAudio::convertVolume(qreal volume, VolumeScale from, VolumeScale to)
Converts an audio \a volume \a from a volume scale \a to another, and returns the result.
Depending on the context, different scales are used to represent audio volume. All Qt Multimedia
classes that have an audio volume use a linear scale, the reason is that the loudness of a
speaker is controlled by modulating its voltage on a linear scale. The human ear on the other
hand, perceives loudness in a logarithmic way. Using a logarithmic scale for volume controls
is therefore appropriate in most applications. The decibel scale is logarithmic by nature and
is commonly used to define sound levels, it is usually used for UI volume controls in
professional audio applications. The cubic scale is a computationally cheap approximation of a
logarithmic scale, it provides more control over lower volume levels.
The following example shows how to convert the volume value from a slider control before passing
it to a QMediaPlayer. As a result, the perceived increase in volume is the same when increasing
the volume slider from 20 to 30 as it is from 50 to 60:
\snippet multimedia-snippets/audio.cpp Volume conversion
\since 5.8
\sa VolumeScale, QMediaPlayer::setVolume(), QAudioOutput::setVolume(),
QAudioInput::setVolume(), QSoundEffect::setVolume(), QMediaRecorder::setVolume()
*/
qreal convertVolume(qreal volume, VolumeScale from, VolumeScale to)
{
switch (from) {
case LinearVolumeScale:
volume = qMax(qreal(0), volume);
switch (to) {
case LinearVolumeScale:
return volume;
case CubicVolumeScale:
return qPow(volume, qreal(1 / 3.0));
case LogarithmicVolumeScale:
return 1 - std::exp(-volume * LOG100);
case DecibelVolumeScale:
if (volume < 0.001)
return qreal(-200);
else
return qreal(20.0) * std::log10(volume);
}
break;
case CubicVolumeScale:
volume = qMax(qreal(0), volume);
switch (to) {
case LinearVolumeScale:
return volume * volume * volume;
case CubicVolumeScale:
return volume;
case LogarithmicVolumeScale:
return 1 - std::exp(-volume * volume * volume * LOG100);
case DecibelVolumeScale:
if (volume < 0.001)
return qreal(-200);
else
return qreal(3.0 * 20.0) * std::log10(volume);
}
break;
case LogarithmicVolumeScale:
volume = qMax(qreal(0), volume);
switch (to) {
case LinearVolumeScale:
if (volume > 0.99)
return 1;
else
return -std::log(1 - volume) / LOG100;
case CubicVolumeScale:
if (volume > 0.99)
return 1;
else
return qPow(-std::log(1 - volume) / LOG100, qreal(1 / 3.0));
case LogarithmicVolumeScale:
return volume;
case DecibelVolumeScale:
if (volume < 0.001)
return qreal(-200);
else if (volume > 0.99)
return 0;
else
return qreal(20.0) * std::log10(-std::log(1 - volume) / LOG100);
}
break;
case DecibelVolumeScale:
switch (to) {
case LinearVolumeScale:
return qPow(qreal(10.0), volume / qreal(20.0));
case CubicVolumeScale:
return qPow(qreal(10.0), volume / qreal(3.0 * 20.0));
case LogarithmicVolumeScale:
if (qFuzzyIsNull(volume))
return 1;
else
return 1 - std::exp(-qPow(qreal(10.0), volume / qreal(20.0)) * LOG100);
case DecibelVolumeScale:
return volume;
}
break;
}
return volume;
}
}
#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug dbg, QAudio::Error error)
{
QDebugStateSaver saver(dbg);
dbg.nospace();
switch (error) {
case QAudio::NoError:
dbg << "NoError";
break;
case QAudio::OpenError:
dbg << "OpenError";
break;
case QAudio::IOError:
dbg << "IOError";
break;
case QAudio::UnderrunError:
dbg << "UnderrunError";
break;
case QAudio::FatalError:
dbg << "FatalError";
break;
}
return dbg;
}
QDebug operator<<(QDebug dbg, QAudio::State state)
{
QDebugStateSaver saver(dbg);
dbg.nospace();
switch (state) {
case QAudio::ActiveState:
dbg << "ActiveState";
break;
case QAudio::SuspendedState:
dbg << "SuspendedState";
break;
case QAudio::StoppedState:
dbg << "StoppedState";
break;
case QAudio::IdleState:
dbg << "IdleState";
break;
}
return dbg;
}
QDebug operator<<(QDebug dbg, QAudio::Mode mode)
{
QDebugStateSaver saver(dbg);
dbg.nospace();
switch (mode) {
case QAudio::AudioInput:
dbg << "AudioInput";
break;
case QAudio::AudioOutput:
dbg << "AudioOutput";
break;
}
return dbg;
}
QDebug operator<<(QDebug dbg, QAudio::Role role)
{
QDebugStateSaver saver(dbg);
dbg.nospace();
switch (role) {
case QAudio::UnknownRole:
dbg << "UnknownRole";
break;
case QAudio::AccessibilityRole:
dbg << "AccessibilityRole";
break;
case QAudio::AlarmRole:
dbg << "AlarmRole";
break;
case QAudio::GameRole:
dbg << "GameRole";
break;
case QAudio::MusicRole:
dbg << "MusicRole";
break;
case QAudio::NotificationRole:
dbg << "NotificationRole";
break;
case QAudio::RingtoneRole:
dbg << "RingtoneRole";
break;
case QAudio::SonificationRole:
dbg << "SonificationRole";
break;
case QAudio::VideoRole:
dbg << "VideoRole";
break;
case QAudio::VoiceCommunicationRole:
dbg << "VoiceCommunicationRole";
break;
}
return dbg;
}
QDebug operator<<(QDebug dbg, QAudio::VolumeScale scale)
{
QDebugStateSaver saver(dbg);
dbg.nospace();
switch (scale) {
case QAudio::LinearVolumeScale:
dbg << "LinearVolumeScale";
break;
case QAudio::CubicVolumeScale:
dbg << "CubicVolumeScale";
break;
case QAudio::LogarithmicVolumeScale:
dbg << "LogarithmicVolumeScale";
break;
case QAudio::DecibelVolumeScale:
dbg << "DecibelVolumeScale";
break;
}
return dbg;
}
#endif
QT_END_NAMESPACE
|
