[asterisk-users] Audacity settings for Asterisk sound files

[Steve Edwards]

> On Sat, Jul 17, 2010 at 6:52 PM, David Shauger <sollostech at gmail.com> 
> wrote:

>> Can anyone provide the settings in Audacity to create a proper wav file 
>> without having to do additional conversion in the cli? Has to be a way 
>> to do this with less steps.

On Sun, 18 Jul 2010, David Backeberg wrote:

> If your goal is to 'minimize steps', you should do a batch on the 
> command line, using Sound eXchange, aka sox.
>
> http://sox.sourceforge.net/
>
> But nobody knows what needs to be converted, nor how, without knowing 
> your source file format.

Not quite true.

(I'm not an expert in this field, so if you are, please correct me.)

Some (most?) file formats contain headers that describe the contents.

For example, the WAV file format contains a header (metadata) that 
describes the "endian-ness," the encoding, the sample size, the number of 
channels and the sample rate. An MP4 file format header would include 
frame rate, frame width & height, duration, number of audio streams, etc.

This is how the "file" command works.

But, the original question is improperly "formed."

Think of the file format as the envelope and the data (the audio) the 
letter within the envelope. As long as the sender formats the metadata on 
the envelope correctly, the USPS can deliver it.

If the letter is written in French, it will be useless to me as a 
mono-lingual American.

In the same way, I doubt Asterisk is not reading the envelope, I suspect 
the OP does not know which "language" Asterisk understands.

Asterisk supports at least 2 encodings in a WAV file -- gsm and pcm.

I suspect the OP is interested in how to format pcm correctly. In sox (my 
tool of choice), the command line options "-c 1 -s -w -r 8000" will do the 
trick.

To save you a trip to the man page, these are:

 	-c 1	-- mono
 	-s	-- signed linear
 	-w	-- 16 bit words
 	-r 8000	-- 8000 samples per second

Audacity should have appropriate check-boxes somewhere in the "export" 
menu item.

-- 
Thanks in advance,
-------------------------------------------------------------------------
Steve Edwards       sedwards at sedwards.com      Voice: +1-760-468-3867 PST
Newline                                              Fax: +1-760-731-3000