The QAudioInput class provides an interface for receiving audio data from an audio input device. More...

#include <qaudioinput.h>

Inheritance diagram for QAudioInput:

Signals
void	notify ()
	This signal is emitted when x ms of audio data has been processed the interval set by setNotifyInterval(x). More...

void	stateChanged (QAudio::State)
	This signal is emitted when the device state has changed. More...

Signals inherited from QObject
void	destroyed (QObject *=0)
	This signal is emitted immediately before the object obj is destroyed, and can not be blocked. More...

Public Functions
int	bufferSize () const
	Returns the audio buffer size in milliseconds. More...

int	bytesReady () const
	Returns the amount of audio data available to read in bytes. More...

qint64	elapsedUSecs () const
	Returns the microseconds since start() was called, including time in Idle and Suspend states. More...

QAudio::Error	error () const
	Returns the error state. More...

QAudioFormat	format () const
	Returns the QAudioFormat being used. More...

int	notifyInterval () const
	Returns the notify interval in milliseconds. More...

int	periodSize () const
	Returns the period size in bytes. More...

qint64	processedUSecs () const
	Returns the amount of audio data processed since start() was called in microseconds. More...

	QAudioInput (const QAudioFormat &format=QAudioFormat(), QObject *parent=0)
	Construct a new audio input and attach it to parent. More...

	QAudioInput (const QAudioDeviceInfo &audioDeviceInfo, const QAudioFormat &format=QAudioFormat(), QObject *parent=0)
	Construct a new audio input and attach it to parent. More...

void	reset ()
	Drops all audio data in the buffers, resets buffers to zero. More...

void	resume ()
	Resumes processing audio data after a suspend(). More...

void	setBufferSize (int bytes)
	Sets the audio buffer size to value milliseconds. More...

void	setNotifyInterval (int milliSeconds)
	Sets the interval for notify() signal to be emitted. More...

void	start (QIODevice *device)
	Uses the device as the QIODevice to transfer data. More...

QIODevice *	start ()
	Returns a pointer to a new QIODevice that will be used to handle the data transfer. More...

QAudio::State	state () const
	Returns the state of audio processing. More...

void	stop ()
	Stops the audio input, detaching from the system resource. More...

void	suspend ()
	Stops processing audio data, preserving buffered audio data. More...

	~QAudioInput ()
	Destroy this audio input. More...

Public Functions inherited from QObject
bool	blockSignals (bool b)
	If block is true, signals emitted by this object are blocked (i.e., emitting a signal will not invoke anything connected to it). More...

const QObjectList &	children () const
	Returns a list of child objects. More...

bool	connect (const QObject sender, const char signal, const char *member, Qt::ConnectionType type=Qt::AutoConnection) const

bool	disconnect (const char signal=0, const QObject receiver=0, const char *member=0)

bool	disconnect (const QObject receiver, const char member=0)

void	dumpObjectInfo ()
	Dumps information about signal connections, etc. More...

void	dumpObjectTree ()
	Dumps a tree of children to the debug output. More...

QList< QByteArray >	dynamicPropertyNames () const
	Returns the names of all properties that were dynamically added to the object using setProperty(). More...

virtual bool	event (QEvent *)
	This virtual function receives events to an object and should return true if the event e was recognized and processed. More...

virtual bool	eventFilter (QObject , QEvent )
	Filters events if this object has been installed as an event filter for the watched object. More...

template<typename T >
T	findChild (const QString &aName=QString()) const
	Returns the child of this object that can be cast into type T and that is called name, or 0 if there is no such object. More...

template<typename T >
QList< T >	findChildren (const QString &aName=QString()) 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. More...

template<typename T >
QList< T >	findChildren (const QRegExp &re) const

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. More...

void	installEventFilter (QObject *)
	Installs an event filter filterObj on this object. More...

bool	isWidgetType () const
	Returns true if the object is a widget; otherwise returns false. More...

void	killTimer (int id)
	Kills the timer with timer identifier, id. More...

virtual const QMetaObject *	metaObject () const
	Returns a pointer to the meta-object of this object. More...

void	moveToThread (QThread *thread)
	Changes the thread affinity for this object and its children. More...

QString	objectName () const

QObject *	parent () const
	Returns a pointer to the parent object. More...

QVariant	property (const char *name) const
	Returns the value of the object's name property. More...

Q_INVOKABLE	QObject (QObject *parent=0)
	Constructs an object with parent object parent. More...

void	removeEventFilter (QObject *)
	Removes an event filter object obj from this object. More...

void	setObjectName (const QString &name)

void	setParent (QObject *)
	Makes the object a child of parent. More...

bool	setProperty (const char *name, const QVariant &value)
	Sets the value of the object's name property to value. More...

void	setUserData (uint id, QObjectUserData *data)

bool	signalsBlocked () const
	Returns true if signals are blocked; otherwise returns false. More...

int	startTimer (int interval)
	Starts a timer and returns a timer identifier, or returns zero if it could not start a timer. More...

QThread *	thread () const
	Returns the thread in which the object lives. More...

QObjectUserData *	userData (uint id) const

virtual	~QObject ()
	Destroys the object, deleting all its child objects. More...

Properties
QAbstractAudioInput *	d

Additional Inherited Members
Public Slots inherited from QObject
void	deleteLater ()
	Schedules this object for deletion. More...

Static Public Functions inherited from QObject
static bool	connect (const QObject sender, const char signal, const QObject receiver, const char member, Qt::ConnectionType=Qt::AutoConnection)
	Creates a connection of the given type from the signal in the sender object to the method in the receiver object. More...

static bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char member)
	Disconnects signal in object sender from method in object receiver. More...

static bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &member)

static uint	registerUserData ()

static QString	tr (const char sourceText, const char comment=0, int n=-1)

static QString	trUtf8 (const char sourceText, const char comment=0, int n=-1)

Static Public Variables inherited from QObject
static const QMetaObject	staticMetaObject
	This variable stores the meta-object for the class. More...

Protected Functions inherited from QObject
virtual void	childEvent (QChildEvent *)
	This event handler can be reimplemented in a subclass to receive child events. More...

virtual void	connectNotify (const char *signal)
	This virtual function is called when something has been connected to signal in this object. More...

virtual void	customEvent (QEvent *)
	This event handler can be reimplemented in a subclass to receive custom events. More...

virtual void	disconnectNotify (const char *signal)
	This virtual function is called when something has been disconnected from signal in this object. More...

	QObject (QObjectPrivate &dd, QObject *parent=0)

int	receivers (const char *signal) const
	Returns the number of receivers connected to the signal. More...

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 0. More...

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *)
	This event handler can be reimplemented in a subclass to receive timer events for the object. More...

Protected Variables inherited from QObject
QScopedPointer< QObjectData >	d_ptr

Static Protected Variables inherited from QObject
static const QMetaObject	staticQtMetaObject

Related Functions inherited from QObject
T	qFindChildqFindChildren (const QObject *obj, const QString &name)()

QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QString &name)()

QList< T >	qFindChildrenqFindChildren (const QObject *obj, const QRegExp &regExp)()

T *	qobject_cast (QObject *object)

	QObjectList

void *	qt_find_obj_child (QObject parent, const char type, const QString &name)
	Returns a pointer to the object named name that inherits type and with a given parent. More...

Detailed Description

The QAudioInput class provides an interface for receiving audio data from an audio input device.

Attention: Module: QtMultimedia

Since: 4.6

You can construct an audio input with the system's default audio input device. It is also possible to create QAudioInput with a specific QAudioDeviceInfo. When you create the audio input, you should also send in the QAudioFormat to be used for the recording (see the QAudioFormat class description for details).

To record to a file:

QAudioInput lets you record audio with an audio input device. The default constructor of this class will use the systems default audio device, but you can also specify a QAudioDeviceInfo for a specific device. You also need to pass in the QAudioFormat in which you wish to record.

Starting up the QAudioInput is simply a matter of calling start() with a QIODevice opened for writing. For instance, to record to a file, you can:

QFile outputFile; // class member.

QAudioInput *audioInput; // class member.

... 4

    void startRecording()
    {
        outputFile.setFileName("/tmp/test.raw");
        outputFile.open( QIODevice::WriteOnly | QIODevice::Truncate );
        QAudioFormat format;
        // set up the format you want, eg.
        format.setFrequency(8000);
        format.setChannels(1);
        format.setSampleSize(8);
        format.setCodec("audio/pcm");
        format.setByteOrder(QAudioFormat::LittleEndian);
        format.setSampleType(QAudioFormat::UnSignedInt);
        QAudioDeviceInfo info = QAudioDeviceInfo::defaultInputDevice();
        if (!info.isFormatSupported(format)) {
            qWarning()<<"default format not supported try to use nearest";
            format = info.nearestFormat(format);
        }
        audioInput = new QAudioInput(format, this);
        QTimer::singleShot(3000, this, SLOT(stopRecording()));
        audioInput->start(&outputFile);
        // Records audio for 3000ms
    }

This will start recording if the format specified is supported by the input device (you can check this with QAudioDeviceInfo::isFormatSupported(). In case there are any snags, use the error() function to check what went wrong. We stop recording in the stopRecording() slot.

    void stopRecording()
    {
        audioInput->stop();
        outputFile.close();
        delete audioInput;
    }

At any point in time, QAudioInput will be in one of four states: active, suspended, stopped, or idle. These states are specified by the QAudio::State enum. You can request a state change directly through suspend(), resume(), stop(), reset(), and start(). The current state is reported by state(). QAudioOutput will also signal you when the state changes (stateChanged()).

QAudioInput provides several ways of measuring the time that has passed since the start() of the recording. The processedUSecs() function returns the length of the stream in microseconds written, i.e., it leaves out the times the audio input was suspended or idle. The elapsedUSecs() function returns the time elapsed since start() was called regardless of which states the QAudioInput has been in.

If an error should occur, you can fetch its reason with error(). The possible error reasons are described by the QAudio::Error enum. The QAudioInput will enter the QAudio::StoppedState when an error is encountered. Connect to the stateChanged() signal to handle the error:

    void stateChanged(QAudio::State newState)
    {
        switch(newState) {
            case QAudio::StoppedState:
            if (audioInput->error() != QAudio::NoError) {
                 // Perform error handling
            } else {
            }
            break;

See also: QAudioOutput, QAudioDeviceInfo

Symbian Platform Security Requirements

On Symbian, processes which use this class must have the UserEnvironment platform security capability. If the client process lacks this capability, calls to either overload of start() will fail. This failure is indicated by the QAudioInput object setting its error() value to QAudio::OpenError and then emitting a stateChanged(QAudio::StoppedState) signal.

Platform security capabilities are added via the TARGET.CAPABILITY qmake variable.

Definition at line 63 of file qaudioinput.h.

Constructors and Destructors

◆ QAudioInput() [1/2]

QAudioInput::QAudioInput	(	const QAudioFormat &	format = `QAudioFormat()`,
		QObject *	parent = `0`
	)

explicit

Construct a new audio input and attach it to parent.

The default audio input device is used with the output format parameters.

Definition at line 138 of file qaudioinput.cpp.

                                                                    :
     QObject(parent)
 {
     d = QAudioDeviceFactory::createDefaultInputDevice(format);
     connect(d, SIGNAL(notify()), SIGNAL(notify()));
     connect(d, SIGNAL(stateChanged(QAudio::State)), SIGNAL(stateChanged(QAudio::State)));
 }

◆ QAudioInput() [2/2]

QAudioInput::QAudioInput	(	const QAudioDeviceInfo &	audioDevice,
		const QAudioFormat &	format = `QAudioFormat()`,
		QObject *	parent = `0`
	)

explicit

Construct a new audio input and attach it to parent.

The device referenced by audioDevice is used with the input format parameters.

Definition at line 152 of file qaudioinput.cpp.

                                                                                                         :
     QObject(parent)
 {
     d = QAudioDeviceFactory::createInputDevice(audioDevice, format);
     connect(d, SIGNAL(notify()), SIGNAL(notify()));
     connect(d, SIGNAL(stateChanged(QAudio::State)), SIGNAL(stateChanged(QAudio::State)));
 }

◆ ~QAudioInput()

QAudioInput::~QAudioInput ( )

Destroy this audio input.

Definition at line 164 of file qaudioinput.cpp.

 {
     delete d;
 }

Functions

◆ bufferSize()

int QAudioInput::bufferSize ( ) const

Returns the audio buffer size in milliseconds.

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 303 of file qaudioinput.cpp.

 {
     return d->bufferSize();
 }

◆ bytesReady()

int QAudioInput::bytesReady ( ) const

Returns the amount of audio data available to read in bytes.

NOTE: returned value is only valid while in QAudio::ActiveState or QAudio::IdleState state, otherwise returns zero.

Definition at line 315 of file qaudioinput.cpp.

 {
     /*
     -If not ActiveState|IdleState, return 0
     -return amount of audio data available to read
     */
     return d->bytesReady();
 }

◆ elapsedUSecs()

qint64 QAudioInput::elapsedUSecs ( ) const

Returns the microseconds since start() was called, including time in Idle and Suspend states.

Definition at line 373 of file qaudioinput.cpp.

 {
     return d->elapsedUSecs();
 }

◆ error()

QAudio::Error QAudioInput::error ( ) const

Returns the error state.

Definition at line 382 of file qaudioinput.cpp.

 {
     return d->error();
 }

◆ format()

QAudioFormat QAudioInput::format ( ) const

Returns the QAudioFormat being used.

Definition at line 226 of file qaudioinput.cpp.

 {
     return d->format();
 }

◆ notify

QAudioInput::notify ( )

signal

This signal is emitted when x ms of audio data has been processed the interval set by setNotifyInterval(x).

Referenced by QAudioInput().

◆ notifyInterval()

int QAudioInput::notifyInterval ( ) const

Returns the notify interval in milliseconds.

Definition at line 353 of file qaudioinput.cpp.

 {
     return d->notifyInterval();
 }

◆ periodSize()

int QAudioInput::periodSize ( ) const

Returns the period size in bytes.

Note: This is the recommended read size in bytes.

Definition at line 330 of file qaudioinput.cpp.

 {
     return d->periodSize();
 }

◆ processedUSecs()

qint64 QAudioInput::processedUSecs ( ) const

Returns the amount of audio data processed since start() was called in microseconds.

Definition at line 363 of file qaudioinput.cpp.

 {
     return d->processedUSecs();
 }

◆ reset()

void QAudioInput::reset ( )

Drops all audio data in the buffers, resets buffers to zero.

Definition at line 247 of file qaudioinput.cpp.

 {
     d->reset();
 }

◆ resume()

void QAudioInput::resume ( )

Resumes processing audio data after a suspend().

Sets error() to QAudio::NoError. Sets state() to QAudio::ActiveState if you previously called start(QIODevice*). Sets state() to QAudio::IdleState if you previously called start(). emits stateChanged() signal.

Definition at line 273 of file qaudioinput.cpp.

 {
      d->resume();
 }

◆ setBufferSize()

void QAudioInput::setBufferSize ( int value )

Sets the audio buffer size to value milliseconds.

Note: This function can be called anytime before start(), calls to this are ignored after start(). It should not be assumed that the buffer size set is the actual buffer size used, calling bufferSize() anytime after start() will return the actual buffer size being used.

Definition at line 288 of file qaudioinput.cpp.

 {
     d->setBufferSize(value);
 }

◆ setNotifyInterval()

void QAudioInput::setNotifyInterval ( int ms )

Sets the interval for notify() signal to be emitted.

This is based on the ms of audio data processed not on actual real-time. The minimum resolution of the timer is platform specific and values should be checked with notifyInterval() to confirm actual value being used.

Definition at line 344 of file qaudioinput.cpp.

 {
     d->setNotifyInterval(ms);
 }

◆ start() [1/2]

void QAudioInput::start ( QIODevice * device )

Uses the device as the QIODevice to transfer data.

Passing a QIODevice allows the data to be transferred without any extra code. All that is required is to open the QIODevice. QAudioInput does not take ownership of device.

The QAudioInput will write to the device when new data is available. You can subclass QIODevice and reimplement QIODevice::writeData() if you wish to access the data. If you simply want to save data to a file, you can pass a QFile to this function.

If able to successfully get audio data from the systems audio device the state() is set to either QAudio::ActiveState or QAudio::IdleState, error() is set to QAudio::NoError and the stateChanged() signal is emitted.

If a problem occurs during this process the error() is set to QAudio::OpenError, state() is set to QAudio::StoppedState and stateChanged() signal is emitted.

QAudioInput::Symbian Platform Security Requirements

See also: QIODevice

Definition at line 192 of file qaudioinput.cpp.

 {
     d->start(device);
 }

◆ start() [2/2]

QIODevice * QAudioInput::start ( )

Returns a pointer to a new QIODevice that will be used to handle the data transfer.

This QIODevice can be used to QIODevice::read() audio data directly. You will typically connect to the QIODevice::readyRead() signal, and read from the device in the slot you connect to. QAudioInput keeps ownership of the device.

If able to access the systems audio device the state() is set to QAudio::IdleState, error() is set to QAudio::NoError and the stateChanged() signal is emitted.

If a problem occurs during this process the error() is set to QAudio::OpenError, state() is set to QAudio::StoppedState and stateChanged() signal is emitted.

QAudioInput::Symbian Platform Security Requirements

See also: QIODevice

Definition at line 217 of file qaudioinput.cpp.

 {
     return d->start(0);
 }

◆ state()

QAudio::State QAudioInput::state ( ) const

Returns the state of audio processing.

Definition at line 391 of file qaudioinput.cpp.

 {
     return d->state();
 }

◆ stateChanged

QAudioInput::stateChanged ( QAudio::State state )

signal

This signal is emitted when the device state has changed.

Referenced by QAudioInput().

◆ stop()

void QAudioInput::stop ( )

Stops the audio input, detaching from the system resource.

Sets error() to QAudio::NoError, state() to QAudio::StoppedState and emit stateChanged() signal.

Definition at line 238 of file qaudioinput.cpp.

 {
     d->stop();
 }

◆ suspend()

void QAudioInput::suspend ( )

Stops processing audio data, preserving buffered audio data.

Sets error() to QAudio::NoError, state() to QAudio::SuspendedState and emit stateChanged() signal.

Definition at line 259 of file qaudioinput.cpp.

 {
     d->suspend();
 }

Properties

◆ d

QAbstractAudioInput* QAudioInput::d

private

Definition at line 104 of file qaudioinput.h.

Referenced by bufferSize(), bytesReady(), elapsedUSecs(), error(), format(), notifyInterval(), periodSize(), processedUSecs(), QAudioInput(), reset(), resume(), setBufferSize(), setNotifyInterval(), start(), state(), stop(), suspend(), and ~QAudioInput().

The documentation for this class was generated from the following files:

/src/multimedia/audio/qaudioinput.h
/src/multimedia/audio/qaudioinput.cpp

Signals

Public Functions

Properties

Additional Inherited Members

Detailed Description

Symbian Platform Security Requirements

Constructors and Destructors

◆ QAudioInput() [1/2]

◆ QAudioInput() [2/2]

◆ ~QAudioInput()

Functions

◆ bufferSize()

◆ bytesReady()

◆ elapsedUSecs()

◆ error()

◆ format()

◆ notify

◆ notifyInterval()

◆ periodSize()

◆ processedUSecs()

◆ reset()

◆ resume()

◆ setBufferSize()

◆ setNotifyInterval()

◆ start() [1/2]

◆ start() [2/2]

◆ state()

◆ stateChanged

◆ stop()

◆ suspend()

Properties

◆ d