[Asterisk-Users] Audio format for announcements

[Steven Critchfield]

On Mon, 2003-12-22 at 09:50, Sean Adams wrote:
> Hi guys. First off, to the folks at Digium: outstanding work. The fact 
> that Asterisk is open source puts you right at the cusp of what will be 
> the most important telecom advance since the transatlantic cable.
> 
> Anyway... a couple newbie questions concerning sound quality - I don't 
> see any reason why the system should not use the best possible format 
> for any given connection.
> 
> 1) Is it possible to store the menu sounds in wav/aiff, and let 
> asterisk compress them to gsm only as necessary? Eg for POTS lines, yes 
> the lines are crap already, but why butcher the sound any further by 
> running it through a speech codec?

If it is recorded well, and is played on decent interfaces, it won't
sound bad. If you so wish, you can store these as wav files in ulaw or
alaw format. Look at the codec list and decide what you wish to do. 

I'm sorry that I have forgotten the name of the person I helped before,
but I hosted a prompt for a person so they could see how much of a
difference a digital link makes for sound quality. I don't think you
would notice a problem no matter what codec within reason if you have a
good link.

> 2) For my internal SIP phones, I don't care about bandwidth usage. What 
> settings will give the best sound quality?  Does the protocol (or for 
> that matter, any particular brand of phones) support uncompressed or 
> very high bit rate audio for intra-pbx calls?

All phones should support ulaw or alaw. Those are pretty much the least
compressed you will get. 
-- 
Steven Critchfield <critch at basesys.com>