[Asterisk-Users] English vs American voice files

[Bill Seddon]

Thanks for your suggestions.  I took at look at man sox and could understand
something less than every other word.  A document written by and for sound
engineers I think.



-----Original Message-----
From: James Cloos [mailto:cloos at jhcloos.com] 
Sent: September 20, 2004 6:18 PM
To: Bill Seddon
Cc: 'Asterisk Users Mailing List - Non-Commercial Discussion'
Subject: Re: [Asterisk-Users] English vs American voice files

>>>>> "Bill" == Bill Seddon <bill.seddon at lyquidity.com> writes:

Bill> My use of sox for down sampling is limited to
Bill> this kind of command:

Bill> sox in.wav -r 8000 out.gsm

You really want to use the polyphase app in sox for resampling.
It is significantly slower than the other options, but that is
irrelevant here.  So try:

sox in.wav -r 8000 out.gsm polyphase

Use out.sl for a slinear file (then rename it to whatever.snl),
out.ul for a mu-law file, out.al for an alaw file, etc.  Cf
show file formats at the * cli.

If you are mostly sending the audio out over a zap channel, you
may as well use ulaw or alaw -- whichever the pstn in your area
uses.  If primarily voip, you can match whichever codec you use
or just make it slinear (.sw in sox; .sln for *) and convert it
on the fly.

-JimC