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Qt
Internal/Contributor docs for the Qt SDK. <b>Note:</b> These are NOT official API docs; those are found <a href='https://doc.qt.io/'>here</a>.
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Qt
Internal/Contributor docs for the Qt SDK. <b>Note:</b> These are NOT official API docs; those are found <a href='https://doc.qt.io/'>here</a>.
|
The QAudioSink class provides an interface for sending audio data to an audio output device. More...
#include <qaudiosink.h>
Inheritance diagram for QAudioSink: Collaboration diagram for QAudioSink:Signals | |
| void | stateChanged (QAudio::State state) |
| This signal is emitted when the device state has changed. | |
| Signals inherited from QObject | |
| void | destroyed (QObject *=nullptr) |
| This signal is emitted immediately before the object obj is destroyed, after any instances of QPointer have been notified, and cannot be blocked. | |
| void | objectNameChanged (const QString &objectName, QPrivateSignal) |
| This signal is emitted after the object's name has been changed. | |
Public Member Functions | |
| QAudioSink (const QAudioFormat &format=QAudioFormat(), QObject *parent=nullptr) | |
| Construct a new audio output and attach it to parent. | |
| QAudioSink (const QAudioDevice &audioDeviceInfo, const QAudioFormat &format=QAudioFormat(), QObject *parent=nullptr) | |
| Construct a new audio output and attach it to parent. | |
| ~QAudioSink () | |
| Destroys this audio output. | |
| bool | isNull () const |
Returns true is the QAudioSink instance is null, otherwise returns false. | |
| QAudioFormat | format () const |
| Returns the QAudioFormat being used. | |
| void | start (QIODevice *device) |
| Starts transferring audio data from the device to the system's audio output. | |
| QIODevice * | start () |
| Returns a pointer to the internal QIODevice being used to transfer data to the system's audio output. | |
| void | stop () |
| Stops the audio output, detaching from the system resource. | |
| void | reset () |
| Drops all audio data in the buffers, resets buffers to zero. | |
| void | suspend () |
| Stops processing audio data, preserving buffered audio data. | |
| void | resume () |
| Resumes processing audio data after a suspend(). | |
| void | setBufferSize (qsizetype bytes) |
| Sets the audio buffer size to value in bytes. | |
| qsizetype | bufferSize () const |
| Returns the audio buffer size in bytes. | |
| qsizetype | bytesFree () const |
| Returns the number of free bytes available in the audio buffer. | |
| qint64 | processedUSecs () const |
| Returns the amount of audio data processed since start() was called (in microseconds). | |
| qint64 | elapsedUSecs () const |
| Returns the microseconds since start() was called, including time in Idle and Suspend states. | |
| QtAudio::Error | error () const |
| Returns the error state. | |
| QtAudio::State | state () const |
| Returns the state of audio processing. | |
| void | setVolume (qreal) |
| Sets the output volume to volume. | |
| qreal | volume () const |
| Returns the volume between 0.0 and 1.0 inclusive. | |
| Public Member Functions inherited from QObject | |
| Q_INVOKABLE | QObject (QObject *parent=nullptr) |
| Constructs an object with parent object parent. | |
| virtual | ~QObject () |
| Destroys the object, deleting all its child objects. | |
| virtual bool | event (QEvent *event) |
| This virtual function receives events to an object and should return true if the event e was recognized and processed. | |
| virtual bool | eventFilter (QObject *watched, QEvent *event) |
| Filters events if this object has been installed as an event filter for the watched object. | |
| QString | objectName () const |
| Q_WEAK_OVERLOAD void | setObjectName (const QString &name) |
| Sets the object's name to name. | |
| void | setObjectName (QAnyStringView name) |
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. | |
| QBindable< QString > | bindableObjectName () |
| bool | isWidgetType () const |
Returns true if the object is a widget; otherwise returns false. | |
| bool | isWindowType () const |
Returns true if the object is a window; otherwise returns false. | |
| bool | isQuickItemType () const |
Returns true if the object is a QQuickItem; otherwise returns false. | |
| bool | signalsBlocked () const noexcept |
Returns true if signals are blocked; otherwise returns false. | |
| bool | blockSignals (bool b) noexcept |
| If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). | |
| QThread * | thread () const |
| Returns the thread in which the object lives. | |
| bool | moveToThread (QThread *thread QT6_DECL_NEW_OVERLOAD_TAIL) |
Changes the thread affinity for this object and its children and returns true on success. | |
| int | startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer) |
| This is an overloaded function that will start a timer of type timerType and a timeout of interval milliseconds. | |
| int | startTimer (std::chrono::nanoseconds time, Qt::TimerType timerType=Qt::CoarseTimer) |
| void | killTimer (int id) |
| Kills the timer with timer identifier, id. | |
| void | killTimer (Qt::TimerId id) |
| template<typename T > | |
| T | findChild (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const |
| Returns the child of this object that can be cast into type T and that is called name, or \nullptr if there is no such object. | |
| template<typename T > | |
| QList< T > | findChildren (QAnyStringView aName, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const |
| Returns all children of this object with the given name that can be cast to type T, or an empty list if there are no such objects. | |
| template<typename T > | |
| T | findChild (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const |
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. | |
| template<typename T > | |
| QList< T > | findChildren (Qt::FindChildOptions options=Qt::FindChildrenRecursively) const |
| This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts. | |
| const QObjectList & | children () const |
| Returns a list of child objects. | |
| void | setParent (QObject *parent) |
| Makes the object a child of parent. | |
| void | installEventFilter (QObject *filterObj) |
| Installs an event filter filterObj on this object. | |
| void | removeEventFilter (QObject *obj) |
| Removes an event filter object obj from this object. | |
| QMetaObject::Connection | connect (const QObject *sender, const char *signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const |
| bool | disconnect (const char *signal=nullptr, const QObject *receiver=nullptr, const char *member=nullptr) const |
| bool | disconnect (const QObject *receiver, const char *member=nullptr) const |
| void | dumpObjectTree () const |
| Dumps a tree of children to the debug output. | |
| void | dumpObjectInfo () const |
| Dumps information about signal connections, etc. | |
| bool | setProperty (const char *name, const QVariant &value) |
| Sets the value of the object's name property to value. | |
| bool | setProperty (const char *name, QVariant &&value) |
| QVariant | property (const char *name) const |
| Returns the value of the object's name property. | |
| QList< QByteArray > | dynamicPropertyNames () const |
| QBindingStorage * | bindingStorage () |
| const QBindingStorage * | bindingStorage () const |
| QObject * | parent () const |
| Returns a pointer to the parent object. | |
| bool | inherits (const char *classname) const |
Returns true if this object is an instance of a class that inherits className or a QObject subclass that inherits className; otherwise returns false. | |
Additional Inherited Members | |
| Public Slots inherited from QObject | |
| void | deleteLater () |
| \threadsafe | |
| Static Public Member Functions inherited from QObject | |
| static QMetaObject::Connection | connect (const QObject *sender, const char *signal, const QObject *receiver, const char *member, Qt::ConnectionType=Qt::AutoConnection) |
| \threadsafe | |
| static QMetaObject::Connection | connect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection) |
| template<typename Func1 , typename Func2 > | |
| static QMetaObject::Connection | connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::ContextTypeForFunctor< Func2 >::ContextType *context, Func2 &&slot, Qt::ConnectionType type=Qt::AutoConnection) |
| template<typename Func1 , typename Func2 > | |
| static QMetaObject::Connection | connect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, Func2 &&slot) |
| static bool | disconnect (const QObject *sender, const char *signal, const QObject *receiver, const char *member) |
| \threadsafe | |
| static bool | disconnect (const QObject *sender, const QMetaMethod &signal, const QObject *receiver, const QMetaMethod &member) |
| static bool | disconnect (const QMetaObject::Connection &) |
| Disconnect a connection. | |
| template<typename Func1 , typename Func2 > | |
| static bool | disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const typename QtPrivate::FunctionPointer< Func2 >::Object *receiver, Func2 slot) |
| template<typename Func1 > | |
| static bool | disconnect (const typename QtPrivate::FunctionPointer< Func1 >::Object *sender, Func1 signal, const QObject *receiver, void **zero) |
| Protected Member Functions inherited from QObject | |
| QObject * | sender () const |
| Returns a pointer to the object that sent the signal, if called in a slot activated by a signal; otherwise it returns \nullptr. | |
| int | senderSignalIndex () const |
| int | receivers (const char *signal) const |
| Returns the number of receivers connected to the signal. | |
| bool | isSignalConnected (const QMetaMethod &signal) const |
| virtual void | timerEvent (QTimerEvent *event) |
| This event handler can be reimplemented in a subclass to receive timer events for the object. | |
| virtual void | childEvent (QChildEvent *event) |
| This event handler can be reimplemented in a subclass to receive child events. | |
| virtual void | customEvent (QEvent *event) |
| This event handler can be reimplemented in a subclass to receive custom events. | |
| virtual void | connectNotify (const QMetaMethod &signal) |
| virtual void | disconnectNotify (const QMetaMethod &signal) |
| QObject (QObjectPrivate &dd, QObject *parent=nullptr) | |
| Protected Attributes inherited from QObject | |
| QScopedPointer< QObjectData > | d_ptr |
| Properties inherited from QObject | |
| QString | objectName |
| the name of this object | |
| Related Symbols inherited from QObject | |
| template< class T > T | qobject_cast (const QObject *object) |
| Returns the given object cast to type T if the object is of type T (or of a subclass); otherwise returns \nullptr. | |
| template< typename T > T | qFindChildqFindChildren (const QObject *obj, const QString &name)() |
| template< typename T > QList< T > | qFindChildrenqFindChildren (const QObject *obj, const QString &name)() |
| QObjectList | |
| \macro Q_CLASSINFO(Name, Value) | |
The QAudioSink class provides an interface for sending audio data to an audio output device.
\inmodule QtMultimedia
You can construct an audio output with the system's default audio output device. It is also possible to create QAudioSink with a specific QAudioDevice. When you create the audio output, you should also send in the QAudioFormat to be used for the playback (see the QAudioFormat class description for details).
To play a file:
Starting to play an audio stream is simply a matter of calling start() with a QIODevice. QAudioSink will then fetch the data it needs from the io device. So playing back an audio file is as simple as:
The file will start playing assuming that the audio system and output device support it. If you run out of luck, check what's up with the error() function.
After the file has finished playing, we need to stop the device:
At any given time, the QAudioSink will be in one of four states: active, suspended, stopped, or idle. These states are described by the QtAudio::State enum. State changes are reported through the stateChanged() signal. You can use this signal to, for instance, update the GUI of the application; the mundane example here being changing the state of a { play/pause } button. You request a state change directly with suspend(), stop(), reset(), resume(), and start().
If an error occurs, you can fetch the \l{QtAudio::Error}{error type} with the error() function. Please see the QtAudio::Error enum for a description of the possible errors that are reported. When QtAudio::UnderrunError is encountered, the state changes to QtAudio::IdleState, when another error is encountered, the state changes to QtAudio::StoppedState. You can check for errors by connecting to the stateChanged() signal:
Definition at line 23 of file qaudiosink.h.
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explicit |
Construct a new audio output and attach it to parent.
The default audio output device is used with the output format parameters.
Definition at line 77 of file qaudiosink.cpp.
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explicit |
Construct a new audio output and attach it to parent.
The device referenced by audioDevice is used with the output format parameters.
Definition at line 87 of file qaudiosink.cpp.
References QObject::connect(), emit, QPlatformMediaIntegration::instance(), QObject::parent(), qWarning, state(), QPlatformAudioSink::state(), stateChanged(), and QAudioStateChangeNotifier::stateChanged().
Here is the call graph for this function:| QAudioSink::~QAudioSink | ( | ) |
Destroys this audio output.
This will release any system resources used and free any buffers.
Definition at line 114 of file qaudiosink.cpp.
| qsizetype QAudioSink::bufferSize | ( | ) | const |
Returns the audio buffer size in bytes.
If called before start(), returns platform default value. If called before start() but setBufferSize() was called prior, returns value set by setBufferSize(). If called after start(), returns the actual buffer size being used. This may not be what was set previously by setBufferSize().
Definition at line 256 of file qaudiosink.cpp.
References QPlatformAudioSink::bufferSize().
Here is the call graph for this function:| qsizetype QAudioSink::bytesFree | ( | ) | const |
Returns the number of free bytes available in the audio buffer.
Definition at line 228 of file qaudiosink.cpp.
References QPlatformAudioSink::bytesFree().
Here is the call graph for this function:| qint64 QAudioSink::elapsedUSecs | ( | ) | const |
Returns the microseconds since start() was called, including time in Idle and Suspend states.
Definition at line 274 of file qaudiosink.cpp.
References QPlatformAudioSink::elapsedTime, QElapsedTimer::nsecsElapsed(), state(), and QAudio::StoppedState.
Here is the call graph for this function:| QtAudio::Error QAudioSink::error | ( | ) | const |
Returns the error state.
Definition at line 282 of file qaudiosink.cpp.
References QPlatformAudioSink::error(), and QAudio::OpenError.
Referenced by AudioOutputExample::handleStateChanged().
Here is the call graph for this function: Here is the caller graph for this function:| QAudioFormat QAudioSink::format | ( | ) | const |
Returns the QAudioFormat being used.
Definition at line 123 of file qaudiosink.cpp.
References QPlatformAudioSink::format().
Here is the call graph for this function:
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inline |
Returns true is the QAudioSink instance is null, otherwise returns false.
Definition at line 32 of file qaudiosink.h.
References d.
| qint64 QAudioSink::processedUSecs | ( | ) | const |
Returns the amount of audio data processed since start() was called (in microseconds).
Definition at line 265 of file qaudiosink.cpp.
References QPlatformAudioSink::processedUSecs().
Here is the call graph for this function:| void QAudioSink::reset | ( | ) |
Drops all audio data in the buffers, resets buffers to zero.
Definition at line 191 of file qaudiosink.cpp.
References QPlatformAudioSink::reset().
Here is the call graph for this function:| void QAudioSink::resume | ( | ) |
Resumes processing audio data after a suspend().
Sets state() to the state the sink had when suspend() was called, and sets error() to QAudioError::NoError. This function does nothing if the audio sink's state is not QtAudio::SuspendedState.
Definition at line 216 of file qaudiosink.cpp.
References QPlatformAudioSink::resume().
Here is the call graph for this function:Sets the audio buffer size to value in bytes.
Definition at line 241 of file qaudiosink.cpp.
References QPlatformAudioSink::setBufferSize().
Here is the call graph for this function:Sets the output volume to volume.
The volume is scaled linearly from 0.0 (silence) to 1.0 (full volume). Values outside this range will be clamped.
The default volume is 1.0.
UI volume controls should usually be scaled non-linearly. For example, using a logarithmic scale will produce linear changes in perceived loudness, which is what a user would normally expect from a volume control. See QtAudio::convertVolume() for more details.
Definition at line 311 of file qaudiosink.cpp.
References qBound(), QPlatformAudioSink::setVolume(), and volume().
Here is the call graph for this function:| QIODevice * QAudioSink::start | ( | ) |
Returns a pointer to the internal QIODevice being used to transfer data to the system's audio output.
The device will already be open and \l{QIODevice::write()}{write()} can write data directly to it.
If the QAudioSink is able to access the system's audio device, state() returns QtAudio::IdleState, error() returns QtAudio::NoError and the stateChanged() signal is emitted.
If a problem occurs during this process, error() returns QtAudio::OpenError, state() returns QtAudio::StoppedState and the stateChanged() signal is emitted.
Definition at line 167 of file qaudiosink.cpp.
References QPlatformAudioSink::elapsedTime, QElapsedTimer::restart(), and QPlatformAudioSink::start().
Here is the call graph for this function:Starts transferring audio data from the device to the system's audio output.
The device must have been opened in the \l{QIODevice::ReadOnly}{ReadOnly} or \l{QIODevice::ReadWrite}{ReadWrite} modes.
If the QAudioSink is able to successfully output audio data, state() returns QtAudio::ActiveState, error() returns QtAudio::NoError and the stateChanged() signal is emitted.
If a problem occurs during this process, error() returns QtAudio::OpenError, state() returns QtAudio::StoppedState and the stateChanged() signal is emitted.
Definition at line 142 of file qaudiosink.cpp.
References device, QPlatformAudioSink::elapsedTime, QElapsedTimer::restart(), and QPlatformAudioSink::start().
Referenced by AudioOutputExample::setup().
Here is the call graph for this function: Here is the caller graph for this function:| QtAudio::State QAudioSink::state | ( | ) | const |
Returns the state of audio processing.
Definition at line 290 of file qaudiosink.cpp.
References QPlatformAudioSink::state(), and QAudio::StoppedState.
Referenced by QAudioSink(), and elapsedUSecs().
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signal |
This signal is emitted when the device state has changed.
This is the current state of the audio output.
Referenced by QAudioSink(), QSoundEffectPrivate::sampleReady(), QSoundEffect::setSource(), AudioOutputExample::setup(), and QFFmpeg::AudioRenderer::updateOutput().
Here is the caller graph for this function:| void QAudioSink::stop | ( | ) |
Stops the audio output, detaching from the system resource.
Sets error() to QtAudio::NoError, state() to QtAudio::StoppedState and emit stateChanged() signal.
Definition at line 181 of file qaudiosink.cpp.
References QPlatformAudioSink::stop().
Referenced by AudioOutputExample::stopAudioOutput().
Here is the call graph for this function: Here is the caller graph for this function:| void QAudioSink::suspend | ( | ) |
Stops processing audio data, preserving buffered audio data.
Sets error() to QtAudio::NoError, state() to QtAudio::SuspendedState and emits stateChanged() signal.
Definition at line 203 of file qaudiosink.cpp.
References QPlatformAudioSink::suspend().
Here is the call graph for this function:| qreal QAudioSink::volume | ( | ) | const |
Returns the volume between 0.0 and 1.0 inclusive.
Definition at line 322 of file qaudiosink.cpp.
References QPlatformAudioSink::volume().
Referenced by setVolume().
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1.10.0