[Asterisk-Users] .gsm voice format

[Dan]

Hi,

> The question about transcoding, if you are going to PSTN via a hardware
> interface, then you might want to store your audio in alaw or ulaw
> format,

It is possible to use Voicemail prompts in alaw or ulaw format?

Thanks,
Dan

----- Original Message ----- 
From: "Steven Critchfield" <critch at basesys.com>
To: <asterisk-users at lists.digium.com>
Sent: Monday, July 14, 2003 6:10 PM
Subject: RE: [Asterisk-Users] .gsm voice format


> On Mon, 2003-07-14 at 09:47, Scott Stingel wrote:
> > Ok, thanks.
> >
> > I should have asked this in the first place: what I'm really getting at
is
> > that I need to record (or convert) prompts in many languages.  I have a
> > number of Windows based tools to do this.  I want to end up with prompts
> > that asterisk can play with the least CPU effort, ie. without
transcoding.
> > Would this be the gsm format?  If so, it sounds like I should record in
Wav
> > format, 8-bit samples?  How to convert to gsm?
>
> First learn sox, it will save you a lot of time dealing with format
> conversions. Next record at 8bit 8k so that what you hear on the
> speakers is the same as what will go out to the phone. Then realize that
> if you record via PCM and let sox convert to whatever you like, you will
> be well off.
>
> The question about transcoding, if you are going to PSTN via a hardware
> interface, then you might want to store your audio in alaw or ulaw
> format, if it is VoIP then whatever codec you might use there, or again
> alaw/ulaw so it is a one hop conversion.
> -- 
> Steven Critchfield  <critch at basesys.com>
>
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