[linux-audio-user] voicemail?

Eric Dantan Rzewnicki rzewnickie at rfa.org
Tue May 24 16:30:10 EDT 2005


On Tue, May 24, 2005 at 08:58:33PM +0100, anahata wrote:
> On Tue, May 24, 2005 at 02:44:04PM -0400, M P Smoak wrote:
> > In my work I use telephone in similar ways.  In both cases, phone calls
> > are data.
> [snip] 
> > But it's too big.  Saving it as a .ogg file with quality = 4 gets it down
> > to about 5 meg, I think.  So the question is what's a good way to shrink 
> > it down?
> For voice you could get away with a lower quality ogg and/or resampling
> to a lower sample rate (digital telephony itself uses 8kHz)
> For the ultimate in voce compression however, there are free GSM
> compression/decompresison tools. In debian the gsm-utils pachage seems
> to the the thing you need, no doubt will pull in all the various libgsm*
> packages too. I haven't used it, but if you can get it to do what you
> want you waon't get better voce compression.
> > what type file will it be that is easily platform independent
> Ogg vorbis is quite portable. Don't know about the GSM tools.

There is also the speex codec, also from xiph.org and wrappable in an
ogg container. It's optimized for speech.

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