Re: Best drawing technology for audio waveforms, envelopes, etc.?
Re: Best drawing technology for audio waveforms, envelopes, etc.?
- Subject: Re: Best drawing technology for audio waveforms, envelopes, etc.?
- From: Steve Israelson <email@hidden>
- Date: Sat, 23 Jun 2007 17:11:41 -0700
BTW, please remember not to make the classic mistake when drawing
audio waveforms, which is to assume that you can zoom out by simply
drawing every Nth point. To zoom out without drawing every point,
at a minimum you must find the minimum and maximum sample values at
each horizontal co-ordinate. I'm sure you wouldn't make this
mistake, but it's so common that I thought I'd mention it here.
No this is incorrect.
You must find the average energy in the group of audio samples that
represent one pixel wide in the x-coord.
The min and max is not good enough.
QSSP takes a further approach and finds the power average of 4 groups
of the samples and then blends them together when it renders one
vertical slice so you can see clearly where most of the audio energy is.
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