QAudio¶
The QAudio namespace contains enums used by the audio classes. More…
Synopsis¶
Static functions¶
def
convertVolume
(volume, from, to)
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
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 and1.0
(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 and1.0
(100%) is full volume.QAudio.LogarithmicVolumeScale
Logarithmic Scale.
0.0
(0%) is silence and1.0
(100%) is full volume. UI volume controls should usually use a logarithmic scale.QAudio.DecibelVolumeScale
Decibel (dB, amplitude) logarithmic scale.
-200
is silence and0
is full volume.See also
New in version 5.8.
- static PySide2.QtMultimedia.QAudio.convertVolume(volume, from, to)¶
- Parameters:
volume – float
from –
VolumeScale
to –
VolumeScale
- Return type:
float
Converts an audio
volume
from
a volume scaleto
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)); }
See also
VolumeScale
setVolume()
setVolume()
setVolume()
setVolume()
setVolume()
© 2022 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.