Most wave editors have a snap to zero crossing function. I am not sure
about audacity but peak and soundtrack pro do.
You probably knew this anyway!

Best
Peiman

2009/2/26 Greg Schroeder :
> Hey all,
> Does anyone here edit audio for looping oscillators from the command line?
> I'm currently trying to cobble together a workflow that doesn't need x11,
> and I don't know how to find zero crossings without "looking" at the sound.
> As always, gpl'ed and currently-maintained is best . . .
> Greg

It would be an interesting idea to create a command line utility to  
analyze, find and crop single-cycle loops from an audio file (is this  
what you mean?) but I don't think any such tool currently exists "from  
the command line."

However, if you do have to "look" at the sound, peak is the way to go.  
It's all about the "Loop Tuner" and it does, of course, snap to zero  
crossings. It shouldn't take very much system resources and you could  
probably still get an earlier version that would work on an older  
computer. I know the process takes a bit of time and attention, and it  
would certainly be a daunting task if you have a lot files that need  
this processing, but it will be a good job in the end.

I really like the idea of a command line utility though. Something  
like that shouldn't difficult to create because the pop that we hear  
from a poorly tuned loop is so easily detectable.

JvA
---------
http://music.jonathanvanatom.com
http://www.myspace.com/vanatom
cyberiam@yahoo.com




On Feb 25, 2009, at 6:57 PM, Greg Schroeder wrote:

> Hey all,
> Does anyone here edit audio for looping oscillators from the command  
> line? I'm currently trying to cobble together a workflow that  
> doesn't need x11, and I don't know how to find zero crossings  
> without "looking" at the sound.
> As always, gpl'ed and currently-maintained is best . . .
> Greg

With a little intuition this should be perfectly possible in Csound.

Have you considered thinking about an orc that analyzes each sample of
an audio file and call it a "zero crossing" when the scalar pressure
values to represent amplitude change signs? (ie. from positive to
negative and vice-versa)

Perhaps the source code to the waveset opcode may be a good place to
start. In the abstract, to answer your question I think Csound is
probably the best tool for this.


-David

On Wed, Feb 25, 2009 at 6:12 PM, Greg Schroeder  wrote:
>
>> I am not sure about audacity
>
> . . . "from the command line" . . .
> . . . "doesn't need x11" . . .
> peak and soundtrack
> " . . .gpl'ed . . . "
> " . . . command line . . ."
>
> I know there are myriad ways to find zero crossings in software, Peiman. I
> want to find and edit to them without a graphical interface to accomodate a
> relatively sluggish computer.
> Greg
>
>
>
>>
>> 2009/2/26 Greg Schroeder :
>> > Hey all,
>> > Does anyone here edit audio for looping oscillators from the command
>> > line?
>> > I'm currently trying to cobble together a workflow that doesn't need
>> > x11,
>> > and I don't know how to find zero crossings without "looking" at the
>> > sound.
>> > As always, gpl'ed and currently-maintained is best . . .
>> > Greg
>>
>>
>> Send bugs reports to this list.
>> To unsubscribe, send email sympa@lists.bath.ac.uk with body "unsubscribe
>> csound"
>

Do you write python?
It's not a problem to pull the file into a numpy array and search / 
edit to your heart's content.
D.

On 26/02/2009, at 11:12 AM, Greg Schroeder wrote:

>
> I am not sure about audacity
> . . . "from the command line" . . .
> . . . "doesn't need x11" . . .
> peak and soundtrack
> " . . .gpl'ed . . . "
> " . . . command line . . ."
>
> I know there are myriad ways to find zero crossings in software,  
> Peiman. I want to find and edit to them without a graphical  
> interface to accomodate a relatively sluggish computer.
> Greg
>
>
>
> 2009/2/26 Greg Schroeder :
> > Hey all,
> > Does anyone here edit audio for looping oscillators from the  
> command line?
> > I'm currently trying to cobble together a workflow that doesn't  
> need x11,
> > and I don't know how to find zero crossings without "looking" at  
> the sound.
> > As always, gpl'ed and currently-maintained is best . . .
> > Greg
>

________________________________________________
David Worrall.
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