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 |
Public Types
| enum | Mode { Null, Input, Output } |
Properties
- description : const QString
- id : const QByteArray
- isDefault : const bool
- mode : const Mode
Public Functions
| QAudioDevice() | |
| QAudioDevice(const QAudioDevice &other) | |
| QAudioDevice(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 |
| QAudioDevice & | operator=(QAudioDevice &&other) |
| QAudioDevice & | operator=(const QAudioDevice &other) |
| 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(QMediaDevices::defaultAudioOutput());
if (!info.isFormatSupported(format)) {
qWarning() << "Raw audio format not supported by backend, cannot play audio.";
return;
}
audio = new QAudioSink(format, this);
connect(audio, QAudioSink::stateChanged, this, &AudioInputExample::handleStateChanged);
audio->start(&sourceFile);
}
The set of available devices can be retrieved from the QMediaDevices class.
For instance:
const auto devices = QMediaDevices::audioOutputs(); for (const QAudioDevice &device : devices) qDebug() << "Device: " << device.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()
Constructs a null QAudioDevice object.
QAudioDevice::QAudioDevice(const QAudioDevice &other)
Constructs a copy of other.
[noexcept] QAudioDevice::QAudioDevice(QAudioDevice &&other)
Move constructs from other.
[noexcept] 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 QtAudio::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.
[noexcept] 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
[noexcept] QAudioDevice &QAudioDevice::operator=(QAudioDevice &&other)
Moves other into this QAudioDevice object.
QAudioDevice &QAudioDevice::operator=(const QAudioDevice &other)
Sets the QAudioDevice object to be equal to other.
bool QAudioDevice::operator==(const QAudioDevice &other) const
Returns true if this QAudioDevice class represents the same audio device as other.