- Qt 5.5
- Qt Multimedia
- QML Types
- AudioEngine QML Type
- Qt 5.5.1 Reference Documentation

# AudioEngine QML Type

Organize all your 3d audio content in one place. More...

Import Statement: | import QtAudioEngine 1.0
Since: | Qt 5.0

- List of all members, including inherited members

## Properties

- categories : map
- dopplerFactor : real
- listener : QtAudioEngine::AudioListener
- liveInstances : int
- loading : bool
- samples : map
- sounds : map
- speedOfSound : real

## Signals

- finishedLoading()
- isLoadingChanged()
- liveInstanceCountChanged()
- ready()

## Detailed Description

`AudioEngine` is part of the QtAudioEngine 1.0 module.

    import QtQuick 2.0
    import QtAudioEngine 1.0

    Rectangle {
        color:"white"
        width: 300
        height: 500

        AudioEngine {
            id:audioengine

            AudioSample {
                name:"explosion"
                source: "explosion-02.wav"
            }

            Sound {
                name:"explosion"
                PlayVariation {
                    sample:"explosion"
                }
            }

            dopplerFactor: 1
            speedOfSound: 343.33 // Approximate speed of sound in air at 20 degrees Celsius

            listener.up:"0,0,1"
            listener.position:"0,0,0"
            listener.velocity:"0,0,0"
            listener.direction:"0,1,0"
        }

        MouseArea {
            anchors.fill: parent
            onPressed: {
                audioengine.sounds["explosion"].play();
            }
        }
    }

`AudioEngine` acts as a central library for configuring all 3d audio content in an app, so you should define only one in your app.

It is mostly used as a container to access other types such as AudioCategory, AudioSample and Sound.

See also AudioCategory, AudioSample, Sound, SoundInstance, AttenuationModelLinear, and AttenuationModelInverse.

## Property Documentation

categories : map

Container of all AudioCategory instances.

dopplerFactor : real

This property holds a simple scaling for the effect of doppler shift.

listener : QtAudioEngine::AudioListener

This property holds the listener object. You can change various properties to affect the 3D positioning of sounds.

See also AudioListener.

liveInstances : int

This property indicates how many live sound instances there are at the moment.

loading : bool

This property indicates if the audio engine is loading any audio sample at the moment. This may be useful if you specified the preloaded property in AudioSample and would like to show a loading screen to the user before all audio samples are loaded.

/sa finishedLoading, AudioSample::preloaded

samples : map

Container of all AudioSample instances.

sounds : map

Container of all Sound instances.

speedOfSound : real

This property holds the reference value of the sound speed (in meters per second) which will be used in doppler shift calculation. The doppler shift calculation is used to emulate the change in frequency in sound that is perceived by an observer when the sound source is travelling towards or away from the observer. The speed of sound depends on the medium the sound is propagating through.

## Signal Documentation

finishedLoading()

This signal is emitted when loading has completed.

The corresponding handler is `onFinishedLoading`.

isLoadingChanged()

This signal is emitted when the loading property changes.

The corresponding handler is `onIsLoadingChanged`.

liveInstanceCountChanged()

This signal is emitted when the number of live instances managed by the AudioEngine is changed.

The corresponding handler is `onLiveInstanceCountChanged`.

ready()

This signal is emitted when the AudioEngine is ready to use.

The corresponding handler is `onReady`.