How to Fade-In/Fade-Out a Sampled/Repeating/Mixed Sound
Dean_Swan at Mitel.COM
Dean_Swan at Mitel.COM
Fri May 5 21:11:59 UTC 2006
Hi Rob,
If you try this:
snd := (SampledSound fromWaveFileNamed: 'aWAVFile.wav').
snd addEnvelope: (VolumeEnvelope exponentialDecay: 0.96).
snd play.
You will hear the effect of the envelope, as desired.
This:
snd storeWAVOnFileNamed: ' out.wav'.
should have done what you want, but obviously it does not. I have spent a
little time tracking this, but I haven't found the problem yet.
I will send another reply when I figure this out (maybe today, or later
this weekend).
-Dean
"Rob Rothwell" <r.j.rothwell at gmail.com>
Sent by: squeak-dev-bounces at lists.squeakfoundation.org
05/03/2006 10:25 PM
Please respond to rjriv; Please respond to The general-purpose Squeak
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To: squeak-dev at lists.squeakfoundation.org
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Subject: How to Fade-In/Fade-Out a Sampled/Repeating/Mixed Sound
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.
For example...
snd := RepeatingSound new.
snd setSound: (SampledSound fromWaveFileNamed: 'aWAVFile.wav') iterations:
1.
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...
Thanks,
Rob
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