QAudio

The QAudio namespace contains enums used by the audio classes. More

Inheritance diagram of PySide2.QtMultimedia.QAudio

Synopsis

Static functions

Detailed Description

PySide2.QtMultimedia.QAudio.Error

Constant

Description

QAudio.NoError

No errors have occurred

QAudio.OpenError

An error occurred opening the audio device

QAudio.IOError

An error occurred during read/write of audio device

QAudio.UnderrunError

Audio data is not being fed to the audio device at a fast enough rate

QAudio.FatalError

A non-recoverable error has occurred, the audio device is not usable at this time.

PySide2.QtMultimedia.QAudio.State

Constant

Description

QAudio.ActiveState

Audio data is being processed, this state is set after start() is called and while audio data is available to be processed.

QAudio.SuspendedState

The audio stream is in a suspended state. Entered after suspend() is called or when another stream takes control of the audio device. In the later case, a call to resume will return control of the audio device to this stream. This should usually only be done upon user request.

QAudio.StoppedState

The audio device is closed, and is not processing any audio data

QAudio.IdleState

The QIODevice passed in has no data and audio system’s buffer is empty, this state is set after start() is called and while no audio data is available to be processed.

QAudio.InterruptedState

This stream is in a suspended state because another higher priority stream currently has control of the audio device. Playback cannot resume until the higher priority stream relinquishes control of the audio device.

PySide2.QtMultimedia.QAudio.Mode

Constant

Description

QAudio.AudioOutput

audio output device

QAudio.AudioInput

audio input device

PySide2.QtMultimedia.QAudio.Role

This enum describes the role of an audio stream.

Constant

Description

QAudio.UnknownRole

The role is unknown or undefined

QAudio.MusicRole

Music

QAudio.VideoRole

Soundtrack from a movie or a video

QAudio.VoiceCommunicationRole

Voice communications, such as telephony

QAudio.AlarmRole

Alarm

QAudio.NotificationRole

Notification, such as an incoming e-mail or a chat request

QAudio.RingtoneRole

Ringtone

QAudio.AccessibilityRole

For accessibility, such as with a screen reader

QAudio.SonificationRole

Sonification, such as with user interface sounds

QAudio.GameRole

Game audio

QAudio.CustomRole

The role is specified by customAudioRole()

See also

setAudioRole()

New in version 5.6.

PySide2.QtMultimedia.QAudio.VolumeScale

This enum defines the different audio volume scales.

Constant

Description

QAudio.LinearVolumeScale

Linear scale. 0.0 (0%) is silence and 1.0 (100%) is full volume. All Qt Multimedia classes that have an audio volume use a linear scale.

QAudio.CubicVolumeScale

Cubic scale. 0.0 (0%) is silence and 1.0 (100%) is full volume.

QAudio.LogarithmicVolumeScale

Logarithmic Scale. 0.0 (0%) is silence and 1.0 (100%) is full volume. UI volume controls should usually use a logarithmic scale.

QAudio.DecibelVolumeScale

Decibel (dB, amplitude) logarithmic scale. -200 is silence and 0 is full volume.

See also

convertVolume()

New in version 5.8.

static PySide2.QtMultimedia.QAudio.convertVolume(volume, from, to)
Parameters
Return type

float

Converts an audio volume from a volume scale to another, and returns the result.

Depending on the context, different scales are used to represent audio volume. All Qt Multimedia classes that have an audio volume use a linear scale, the reason is that the loudness of a speaker is controlled by modulating its voltage on a linear scale. The human ear on the other hand, perceives loudness in a logarithmic way. Using a logarithmic scale for volume controls is therefore appropriate in most applications. The decibel scale is logarithmic by nature and is commonly used to define sound levels, it is usually used for UI volume controls in professional audio applications. The cubic scale is a computationally cheap approximation of a logarithmic scale, it provides more control over lower volume levels.

The following example shows how to convert the volume value from a slider control before passing it to a QMediaPlayer . As a result, the perceived increase in volume is the same when increasing the volume slider from 20 to 30 as it is from 50 to 60:

void applyVolume(int volumeSliderValue)
{
    // volumeSliderValue is in the range [0..100]

    qreal linearVolume = QAudio::convertVolume(volumeSliderValue / qreal(100.0),
                                               QAudio::LogarithmicVolumeScale,
                                               QAudio::LinearVolumeScale);

    player.setVolume(qRound(linearVolume * 100));
}