[linux-audio-dev] Waveform

[Fons Adriaensen]

On Tue, May 10, 2005 at 12:23:50AM +0200, Albert Graef wrote:

> Well, I guess the way it's done in most audio editors is that you draw a 
> vertical line between the min and max (and maybe also the rms on top of 
> that), if a single pixel has to represent multiple samples, and the 
> usual connect-the-points-with-lines thingy (or splines, if you prefer 
> smooth curves), when zoomed in to the sample or sub-sample level. Is 
> there a better way?

I've been thinking about a JA-scope companion to JAAA for some months
now, and it's by no means trivial to get something that even starts
to approach an analog scope. 

First, if you want to display the real analog waveform (and that's 
what users will expect), you have to interpolate to at least 1/4
sample. To have good triggering, again more interpolation to find
the exact time the waveform crosses the trigger level. Then again
interpolate to find the y-values corresponding to the pixel positions.

-- 
FA