How to Fade-In/Fade-Out a Sampled/Repeating/Mixed Sound
r.j.rothwell at gmail.com
Thu May 4 02:25:27 UTC 2006
Does anyone know how to fade a mixed sound? I am creating a MixedSound
which includes both a RepeatingSound (based on a looped SampledSound from a
WAV file), and an FMSound.
I pretty much know how to apply a VolumeEnvelope to an FMSound by looking at
the exponentialDecay method, but applying a VolumeEnvelope to a
SampledSound, RepeatingSound, or MixedSound seems to have no effect.
snd := RepeatingSound new.
snd setSound: (SampledSound fromWaveFileNamed: 'aWAVFile.wav') iterations:
snd addEnvelope: (VolumeEnvelope exponentialDecay: 0.96).
snd storeWAVOnFileNamed: 'out.wav'.
...shows no effect on the waveforms in the resulting WAV file, even if I
change the step size of the increments in the exponentialDecay to drag the
decay out much further...
Do I need to write a method to modify the SoundBuffer values of the
SampledSound directly? If so, I'm afraid I will need much more help!
I just don't know enough technically about sound generation to trace my way
through the updateTargetAt method of the VolumeEnvelope class to figure out
what is going on with a non-FMSound...
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