QAudioSource 类

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

头：	#include <QAudioSource>
CMake:	find_package(Qt6 REQUIRED COMPONENTS Multimedia) target_link_libraries(mytarget PRIVATE Qt6::Multimedia)
qmake:	QT += multimedia
继承：	QObject

所有成员列表，包括继承成员

公共函数

	QAudioSource (const QAudioFormat & format = QAudioFormat(), QObject * parent = nullptr)
	QAudioSource (const QAudioDevice & audioDevice , const QAudioFormat & format = QAudioFormat(), QObject * parent = nullptr)
virtual	~QAudioSource ()
qsizetype	bufferSize () const
qsizetype	bytesAvailable () const
qint64	elapsedUSecs () const
QAudio::Error	error () const
QAudioFormat	format () const
bool	isNull () const
qint64	processedUSecs () const
void	reset ()
void	resume ()
void	setBufferSize (qsizetype value )
void	setVolume (qreal volume )
void	start (QIODevice * device )
QIODevice *	start ()
QAudio::State	state () const
void	stop ()
void	suspend ()
qreal	volume () const

信号

void	stateChanged (QAudio::State state )

详细描述

可以采用系统默认音频输入设备构建音频输入。也可以创建 QAudioSource 采用特定 QAudioDevice 。当创建音频输入时，还应发送 QAudioFormat 用于录制 (见 QAudioFormat 类描述了解细节)。

要录制到文件：

QAudioSource 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 QAudioDevice for a specific device. You also need to pass in the QAudioFormat in which you wish to record.

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

QFile destinationFile;   // Class member
QAudioSource* audio; // Class member
{
    destinationFile.setFileName("/tmp/test.raw");
    destinationFile.open( QIODevice::WriteOnly | QIODevice::Truncate );
    QAudioFormat format;
    // Set up the desired format, for example:
    format.setSampleRate(8000);
    format.setChannelCount(1);
    format.setSampleFormat(QAudioFormat::UInt8);
    QAudioDevice info = QMediaDevices::defaultAudioInput();
    if (!info.isFormatSupported(format)) {
        qWarning() << "Default format not supported, trying to use the nearest.";
    }
    audio = new QAudioSource(format, this);
    connect(audio, SIGNAL(stateChanged(QAudio::State)), this, SLOT(handleStateChanged(QAudio::State)));
    QTimer::singleShot(3000, this, SLOT(stopRecording()));
    audio->start(&destinationFile);
    // Records audio for 3000ms
}

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

void AudioInputExample::stopRecording()
{
    audio->stop();
    destinationFile.close();
    delete audio;
}

At any point in time, QAudioSource 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 ()，和 start (). The current state is reported by state (). QAudioSink will also signal you when the state changes ( stateChanged ()).

QAudioSource 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 QAudioSource 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 QAudioSource will enter the StoppedState when an error is encountered. Connect to the stateChanged () signal to handle the error:

void AudioInputExample::handleStateChanged(QAudio::State newState)
{
    switch (newState) {
        case QAudio::StoppedState:
            if (audio->error() != QAudio::NoError) {
                // Error handling
            } else {
                // Finished recording
            }
            break;
        case QAudio::ActiveState:
            // Started recording - read from IO device
            break;
        default:
            // ... other cases as appropriate
            break;
    }
}

另请参阅 QAudioSink and QAudioDevice .

成员函数文档编制

`[explicit]` QAudioSource:: QAudioSource (const QAudioFormat & format = QAudioFormat(), QObject * parent = nullptr)

Construct a new audio input and attach it to parent . The default audio input device is used with the output format 参数。

`[explicit]` QAudioSource:: QAudioSource (const QAudioDevice & audioDevice , const QAudioFormat & format = QAudioFormat(), QObject * parent = nullptr)

Construct a new audio input and attach it to parent . The device referenced by audioDevice is used with the input format 参数。

`[虚拟]` QAudioSource:: ~QAudioSource ()

Destroy this audio input.

qsizetype QAudioSource:: 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 ().

另请参阅 setBufferSize ().

qsizetype QAudioSource:: bytesAvailable () 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.

qint64 QAudioSource:: elapsedUSecs () const

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

QAudio::Error QAudioSource:: error () const

返回错误状态。

QAudioFormat QAudioSource:: format () const

返回 QAudioFormat 被使用。

bool QAudioSource:: isNull () const

返回 true if the audio source is null ，否则返回 false .

qint64 QAudioSource:: processedUSecs () const

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

void QAudioSource:: reset ()

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

void QAudioSource:: resume ()

Resumes processing audio data after a suspend ().

设置 error () 到 QAudio::NoError . Sets state () 到 QAudio::ActiveState if you previously called start( QIODevice *). Sets state () 到 QAudio::IdleState if you previously called start (). emits stateChanged () 信号。

void QAudioSource:: setBufferSize ( qsizetype value )

Sets the audio buffer size to value 字节。

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.

另请参阅 bufferSize ().

void QAudioSource:: setVolume ( qreal volume )

Sets the input volume to volume .

The volume is scaled linearly from 0.0 (无声) 到 1.0 (full volume). Values outside this range will be clamped.

If the device does not support adjusting the input volume then volume will be ignored and the input volume will remain at 1.0.

默认音量为 1.0 .

Note: Adjustments to the volume will change the volume of this audio stream, not the global volume.

另请参阅 volume ().

void QAudioSource:: start ( QIODevice * device )

开始将音频数据从系统的音频输入传输到 device 。 device 必须已打开以 WriteOnly , 追加 or ReadWrite 模式。

若 QAudioSource 能够成功获取音频数据， state () 返回 QAudio::ActiveState or QAudio::IdleState , error () 返回 QAudio::NoError 和 stateChanged () 信号被发射。

若在此过程中出现问题， error () 返回 QAudio::OpenError , state () 返回 QAudio::StoppedState 和 stateChanged () 信号被发射。

另请参阅 QIODevice .

QIODevice *QAudioSource:: start ()

返回的指针指向内部 QIODevice 用于传输来自系统音频输入的数据。设备已打开且 read () can read data directly from it.

注意： 指针将变为无效，在流被停止或启动另一个流之后。

若 QAudioSource 能够访问系统音频设备， state () 返回 QAudio::IdleState , error () 返回 QAudio::NoError 和 stateChanged () 信号被发射。

若在此过程中出现问题， error () 返回 QAudio::OpenError , state () 返回 QAudio::StoppedState 和 stateChanged () 信号被发射。

另请参阅 QIODevice .

QAudio::State QAudioSource:: state () const

返回音频处理的状态。

`[signal]` void QAudioSource:: stateChanged ( QAudio::State state )

此信号被发射当设备 state 已改变。

void QAudioSource:: stop ()

Stops the audio input, detaching from the system resource.

设置 error () 到 QAudio::NoError , state () 到 QAudio::StoppedState and emit stateChanged () 信号。

void QAudioSource:: suspend ()

Stops processing audio data, preserving buffered audio data.

设置 error () 到 QAudio::NoError , state () 到 QAudio::SuspendedState and emit stateChanged () 信号。

qreal QAudioSource:: volume () const

返回输入音量。

If the device does not support adjusting the input volume the returned value will be 1.0.

另请参阅 setVolume ().