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VolumeFaderEffect Class Reference
(Phonon::VolumeFaderEffect)
[
Phonon module]

Audio effect to gradually fade the audio volume. Author: Matthias Kretz <kretz@kde.org> More...

Public Types

Properties

Public Functions

Public Slots


Detailed Description

Audio effect to gradually fade the audio volume. Author: Matthias Kretz <kretz@kde.org>

This effect differs from gradually changing the output volume in that a dedicated effect can change the volume in the smallest possible steps while every other volume control will make more or less noticeable steps.

See also AudioOutput::volume.


Member Type Documentation

enum VolumeFaderEffect::FadeCurve

Determines the curve of the volume change.

ConstantValueDescription
Phonon::VolumeFaderEffect::Fade3Decibel0Crossfade curve/fast fade out. This is the default fade curve.
Phonon::VolumeFaderEffect::Fade6Decibel1Linear fade out.
Phonon::VolumeFaderEffect::Fade9Decibel2Slow fade out.
Phonon::VolumeFaderEffect::Fade12Decibel3A more extreme version of the -9dB fade.

Notes:

Fade3Decibel is often the best fade for a crossfade, as after half of the time the volume reached -3dB. This means that half the possible power (which is proportional to the square of the voltage) is reached. Summed, the maximum power of two audio signals fading with a -3dB curve will always be equal.

For fading in or out the -3dB curve is too abrupt in the end.

With a -6dB fade curve, a volume of -6dB is reached after half of the fading time. -6dB is equal to half of the voltage meaning that the voltage multiplier changes linearly from the start of the fade to the end.

With the Fade9Decibel fade, a volume of -9dB is reached after half of the fade time, so the fade is fast in the beginning and slow at the end. This is a good fade for ending music.


Property Documentation

fadeCurve : FadeCurve

This property holds the fade curve to be used for the fadeIn(), fadeOut() and fadeTo() slots.

Defaults to Fade3Decibel.

Access functions:

See also FadeCurve.

volume : float

This is the current volume of the output as voltage factor. Setting this property changes the volume immediately.

1.0 means 100%, 0.5 means 50% voltage/25% power, 0.0 means 0%

Access functions:

See also volumeDecibel.

volumeDecibel : double

This is the current volume of the output in decibel. Setting this property changes the volume immediately.

0 dB means no change in volume, -6dB means an attenuation of the voltage to 50% and an attenuation of the power to 25%, -inf dB means silence.

Access functions:

See also volume.


Member Function Documentation

void VolumeFaderEffect::fadeIn ( int fadeTime )   [slot]

Tells the Fader to change the volume from the current volume to 100% in fadeTime milliseconds.

Short for fadeTo(1.0, fadeTime).

fadeTime the fade duration in milliseconds

See also fadeTo() and volume.

void VolumeFaderEffect::fadeOut ( int fadeTime )   [slot]

Tells the Fader to change the volume from the current volume to 0% in fadeTime milliseconds. Short for fadeTo(0.0, fadeTime).

fadeTime the fade duration in milliseconds

See also fadeTo.

void VolumeFaderEffect::fadeTo ( float volume, int fadeTime )   [slot]

Tells the Fader to change the volume from the current value to volume in fadeTime milliseconds.

See also fadeIn() and fadeOut().


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