[Asterisk-Users] wav instead of gsm for vm-sounds?

[Damon Estep]

> > Damon Estep wrote:
> >
> > > What I can not decipher is what file name extension should be
used,
> > > should it be a .wav file encoded at 8k/8b/mono? Or are you telling
> me
> > > that it should be .ulaw
> >
> > What I listed were file name extensions as recognized by Asterisk's
> > format modules and sox (and other tools).
> >
> > WAV at 8KHz 8-bit mono is _not_ the same thing as ulaw; WAV is not
> > compressed (normally), so that would be 8 bits of dynamic range.
ulaw
> > and alaw are 8-bit compressed formats, with 13/14 bits of dynamic
> range
> > (this is all documented on the wiki too, I think).
> 

For others that may find this archived in the future!

If using zaptel and g.711u you would want sound files saved in the ulaw
format, so record at a higher quality, maybe 16bit, 8khz, mono WAV and
the use sox to convert to ulaw

Sox does not recognize .ulaw as a format so use .ul - both asterisk and
sox recognize that extension

# sox sound.wav sound.ul

The quality, as Kevin mentioned, is far better than raw 8bit pcm.

Having a set of files with the .ul extension present on the system will
result in asterisk picking those files when the call is g.711u or zap.