- Qt 6.4
- Qt Multimedia
- C++ Classes
- QtMultimedia
- QAudioDevice
- Qt 6.4.2 Reference Documentation

# QAudioDevice Class

The QAudioDevice class provides an information about audio devices and their functionality. More...

Header: | #include <QAudioDevice>
CMake: | find_package(Qt6 REQUIRED COMPONENTS Multimedia) target_link_libraries(mytarget PRIVATE Qt6::Multimedia)
qmake: | QT += multimedia

- List of all members, including inherited members

## Public Types

enum | Mode { Null, Input, Output }

## Properties

- description : const QString
- id : const QByteArray
- isDefault : const bool
- mode : const Mode

## Public Functions

| QAudioDevice(QAudioDevice &&other)
| QAudioDevice(const QAudioDevice &other)
| QAudioDevice()
QAudioDevice & | operator=(const QAudioDevice &other)
QAudioDevice & | operator=(QAudioDevice &&other)
| ~QAudioDevice()
QAudioFormat::ChannelConfig | channelConfiguration() const
QString | description() const
QByteArray | id() const
bool | isDefault() const
bool | isFormatSupported(const QAudioFormat &settings) const
bool | isNull() const
int | maximumChannelCount() const
int | maximumSampleRate() const
int | minimumChannelCount() const
int | minimumSampleRate() const
QAudioDevice::Mode | mode() const
QAudioFormat | preferredFormat() const
QList<QAudioFormat::SampleFormat> | supportedSampleFormats() const
void | swap(QAudioDevice &other)
bool | operator!=(const QAudioDevice &other) const
bool | operator==(const QAudioDevice &other) const

## Detailed Description

QAudioDevice describes an audio device available in the system, either for input or for playback.

A QAudioDevice is used by Qt to construct classes that communicate with the device -- such as QAudioSource, and QAudioSink. It is also used to determine the input or output device to use in a capture session or during media playback.

You can also query each device for the formats it supports. A format in this context is a set consisting of a channel count, sample rate, and sample type. A format is represented by the QAudioFormat class.

The values supported by the device for each of these parameters can be fetched with minimumChannelCount(), maximumChannelCount(), minimumSampleRate(), maximumSampleRate() and supportedSampleFormats(). The combinations supported are dependent on the audio device capabilities. If you need a specific format, you can check if the device supports it with isFormatSupported(). For instance:

     {
         sourceFile.setFileName("/tmp/test.raw");
         sourceFile.open(QIODevice::ReadOnly);

         QAudioFormat format;
         // Set up the format, eg.
         format.setSampleRate(8000);
         format.setChannelCount(1);
         format.setSampleFormat(QAudioFormat::UInt8);

         QAudioDevice info(QAudioDevice::defaultOutputDevice());
         if (!info.isFormatSupported(format)) {
             qWarning() << "Raw audio format not supported by backend, cannot play audio.";
             return;
         }

         audio = new QAudioSink(format, this);
         connect(audio, SIGNAL(stateChanged(QAudio::State)), this, SLOT(handleStateChanged(QAudio::State)));
         audio->start(&sourceFile);
     }

The set of available devices can be retrieved from the QMediaDevices class.

For instance:

     const auto deviceInfos = QMediaDevices::availableDevices(QAudioDevice::Output);
     for (const QAudioDevice &deviceInfo : deviceInfos)
         qDebug() << "Device: " << deviceInfo.description();

In this code sample, we loop through all devices that are able to output sound, i.e., play an audio stream in a supported format. For each device we find, we simply print the deviceName().

See also QAudioSink, QAudioSource, and QAudioFormat.

## Member Type Documentation

### enum QAudioDevice::Mode

Describes the mode of this device.

Constant | Value | Description
--- | --- | ---
`QAudioDevice::Null` | `0` | A null device.
`QAudioDevice::Input` | `1` | An input device.
`QAudioDevice::Output` | `2` | An output device.

## Property Documentation

### `[read-only]` description : const QString

Returns a human readable name of the audio device.

Use this string to present the device to the user.

Access functions:

QString | description() const

### `[read-only]` id : const QByteArray

Returns an identifier for the audio device.

Device names vary depending on the platform/audio plugin being used.

They are a unique identifier for the audio device.

Access functions:

QByteArray | id() const

### `[read-only]` isDefault : const bool

Returns true if this is the default audio device.

Access functions:

bool | isDefault() const

### `[read-only]` mode : const Mode

Returns whether this device is an input or output device.

Access functions:

QAudioDevice::Mode | mode() const

## Member Function Documentation

### QAudioDevice::QAudioDevice(QAudioDevice &&other)

Move constructs from other.

### QAudioDevice::QAudioDevice(const QAudioDevice &other)

Constructs a copy of other.

### QAudioDevice::QAudioDevice()

Constructs a null QAudioDevice object.

### QAudioDevice &QAudioDevice::operator=(const QAudioDevice &other)

Sets the QAudioDevice object to be equal to other.

### QAudioDevice &QAudioDevice::operator=(QAudioDevice &&other)

Moves other into this QAudioDevice object.

### QAudioDevice::~QAudioDevice()

Destroy this audio device info.

### QAudioFormat::ChannelConfig QAudioDevice::channelConfiguration() const

Returns the channel configuration of the device.

### bool QAudioDevice::isFormatSupported(const QAudioFormat &settings) const

Returns true if the supplied settings are supported by the audio device described by this QAudioDevice.

### bool QAudioDevice::isNull() const

Returns whether this QAudioDevice object holds a valid device definition.

### int QAudioDevice::maximumChannelCount() const

Returns the maximum number of supported channel counts.

This is typically 1 for mono sound, or 2 for stereo sound.

### int QAudioDevice::maximumSampleRate() const

Returns the maximum supported sample rate (in Hertz).

### int QAudioDevice::minimumChannelCount() const

Returns the minimum number of supported channel counts.

This is typically 1 for mono sound, or 2 for stereo sound.

### int QAudioDevice::minimumSampleRate() const

Returns the minimum supported sample rate (in Hertz).

### QAudioFormat QAudioDevice::preferredFormat() const

Returns the default audio format settings for this device.

These settings are provided by the platform/audio plugin being used.

They are also dependent on the QAudio::Mode being used.

A typical audio system would provide something like:

- Input settings: 48000Hz mono 16 bit.
- Output settings: 48000Hz stereo 16 bit.

### QList<QAudioFormat::SampleFormat> QAudioDevice::supportedSampleFormats() const

Returns a list of supported sample types.

### void QAudioDevice::swap(QAudioDevice &other)

Swaps the audio device with the other.

### bool QAudioDevice::operator!=(const QAudioDevice &other) const

Returns true if this QAudioDevice class represents a different audio device than other

### bool QAudioDevice::operator==(const QAudioDevice &other) const

Returns true if this QAudioDevice class represents the same audio device as other.