Re: [SoX-users] ISDN A-Law Format

[Kerstin E. <ke...@he...>]

> >
> > It appears to have been left out of the SoX man pages but an extensi=
on
> > of ".al" should represent raw alaw data.
> >
> > One note since you specifically mentioned ISDN.  I have no experienc=
e
> > with it but I ran across a posting in comp.dsp that mentioned that y=
ou
> > need to XOR all incoming data with 0x55 before processing it as alaw=

> > data.  Your conversion will most likely result in noise if your data=

> > needs this XOR.
> >
> > I also saw something about needing to reverse the bits but this is
> > probably more of a hardware dependent thing and their (mis)
> > understanding of telecom standards and how they generally represent =

bit
> > 1 as the most significant bit.
> >
> > If someone has experience with ISDN and can give a definitive answer=
=20
on
> > these issues we could probably create an ISDN file handler in sox th=
at
> > took care of XOR'ing and bit reversal.
> >

It does now work at our side.:-)
I need to convert data do raw alaw data (with sox) and after that=20
reverse the bits, nothing more. Just:
> sox sound.wav sound.al
> cat sound.al | al2alaw > sound.alaw

As al2alaw is very short, I send it with this mail. (FYI)

Thanks for your help.

Kerstin=20