CopperSpice API  1.7.2
QAudioDeviceInfo Class Reference

The QAudioDeviceInfo class provides an interface to query audio devices and their functionality. More...

Public Methods

 QAudioDeviceInfo ()
 
 QAudioDeviceInfo (const QAudioDeviceInfo &other)
 
 ~QAudioDeviceInfo ()
 
QString deviceName () const
 
bool isFormatSupported (const QAudioFormat &format) const
 
bool isNull () const
 
QAudioFormat nearestFormat (const QAudioFormat &format) const
 
bool operator!= (const QAudioDeviceInfo &other) const
 
QAudioDeviceInfo & operator= (const QAudioDeviceInfo &other)
 
bool operator== (const QAudioDeviceInfo &other) const
 
QAudioFormat preferredFormat () const
 
QList< QAudioFormat::EndiansupportedByteOrders () const
 
QList< int > supportedChannelCounts () const
 
QStringList supportedCodecs () const
 
QList< int > supportedSampleRates () const
 
QList< int > supportedSampleSizes () const
 
QList< QAudioFormat::SampleTypesupportedSampleTypes () const
 

Static Public Methods

static QList< QAudioDeviceInfo > availableDevices (QAudio::Mode mode)
 
static QAudioDeviceInfo defaultInputDevice ()
 
static QAudioDeviceInfo defaultOutputDevice ()
 

Detailed Description

The QAudioDeviceInfo class provides an interface to query audio devices and their functionality.

QAudioDeviceInfo lets you query for audio devices such as sound cards and USB headsets that are currently available on the system. The audio devices available are dependent on the platform or audio plugins installed.

You can also query each device for the formats it supports. A format in this context is a set consisting of a specific byte order, channel, codec, frequency, 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 supportedByteOrders(), supportedChannelCounts(), supportedCodecs(), supportedSampleRates(), supportedSampleSizes(), and supportedSampleTypes(). The combinations supported are dependent on the platform, audio plugins installed and the audio device capabilities. If you need a specific format, you can check if the device supports it with isFormatSupported(), or fetch a supported format that is as close as possible to the format with nearestFormat(). For instance:

QAudioFormat format;
format.setFrequency(44100);
...
format.setSampleType(QAudioFormat::SignedInt);
if (!info.isFormatSupported(format)) {
format = info.nearestFormat(format);
}

A QAudioDeviceInfo is used by CopperSpice to construct classes that communicate with the device–such as QAudioInput, and QAudioOutput. The static functions defaultInputDevice(), defaultOutputDevice(), and availableDevices() let you get a list of all available devices. Devices are fetch according to the value of mode this is specified by the QAudio::Mode enum. The QAudioDeviceInfo returned are only valid for the QAudio::Mode.

For instance:

for(const QAudioDeviceInfo &deviceInfo : QAudioDeviceInfo::availableDevices(QAudio::AudioOutput)) {
qDebug() << "Device name: " << deviceInfo.deviceName();
}

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
QAudioOutput, QAudioInput

Constructor & Destructor Documentation

QAudioDeviceInfo::QAudioDeviceInfo ( )

Constructs an empty QAudioDeviceInfo object.

QAudioDeviceInfo::QAudioDeviceInfo ( const QAudioDeviceInfo &  other)

Constructs a copy of other.

QAudioDeviceInfo::~QAudioDeviceInfo ( )

Destroy this audio device info.

Method Documentation

QList< QAudioDeviceInfo > QAudioDeviceInfo::availableDevices ( QAudio::Mode  mode)
static

Returns a list of audio devices that support mode.

QAudioDeviceInfo QAudioDeviceInfo::defaultInputDevice ( )
static

Returns the name of the default input audio device. All platform and audio plugin implementations provide a default audio device to use.

QAudioDeviceInfo QAudioDeviceInfo::defaultOutputDevice ( )
static

Returns the name of the default output audio device. All platform and audio plugin implementations provide a default audio device to use.

QString QAudioDeviceInfo::deviceName ( ) const

Returns human readable name of audio device. Device names vary depending on platform/audio plugin being used. They are a unique string identifiers for the audio device.

For example, default, Intel, or U0x46d0x9a4.

bool QAudioDeviceInfo::isFormatSupported ( const QAudioFormat settings) const

Returns true if settings are supported by the audio device of this QAudioDeviceInfo.

bool QAudioDeviceInfo::isNull ( ) const

Returns whether this QAudioDeviceInfo object holds a device definition.

QAudioFormat QAudioDeviceInfo::nearestFormat ( const QAudioFormat settings) const

Returns closest QAudioFormat to settings that system audio supports. These settings are provided by the platform/audio plugin being used. They also are dependent on the QAudio::Mode being used.

bool QAudioDeviceInfo::operator!= ( const QAudioDeviceInfo &  other) const

Documentation pending.

QAudioDeviceInfo & QAudioDeviceInfo::operator= ( const QAudioDeviceInfo &  other)

Sets the QAudioDeviceInfo object to be equal to other.

bool QAudioDeviceInfo::operator== ( const QAudioDeviceInfo &  other) const

Documentation pending.

QAudioFormat QAudioDeviceInfo::preferredFormat ( ) const

Returns QAudioFormat of default settings. These settings are provided by the platform/audio plugin being used. They also are dependent on the QAudio::Mode being used.

A typical audio system would provide something like:

  • Input settings: 8000Hz mono 8 bit.
  • Output settings: 44100Hz stereo 16 bit little endian.
QList< QAudioFormat::Endian > QAudioDeviceInfo::supportedByteOrders ( ) const

Returns a list of supported byte orders.

QList< int > QAudioDeviceInfo::supportedChannelCounts ( ) const

Returns a list of supported channel counts.

QStringList QAudioDeviceInfo::supportedCodecs ( ) const

Returns a list of supported codecs. All platform and plugin implementations should provide support for:

"audio/pcm" - Linear PCM

For writing plugins to support additional codecs refer to the following:

Refer to the IANA media types for more information.

QList< int > QAudioDeviceInfo::supportedSampleRates ( ) const

Returns a list of supported sample rates.

QList< int > QAudioDeviceInfo::supportedSampleSizes ( ) const

Returns a list of supported sample sizes.

QList< QAudioFormat::SampleType > QAudioDeviceInfo::supportedSampleTypes ( ) const

Returns a list of supported sample types.