freebsd-skq/usr.sbin/i4b/g711conv/g711conv.1
2005-01-18 20:02:45 +00:00

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.\"
.\" Copyright (c) 1999 Hellmuth Michaelis. All rights reserved.
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.\" $Id: g711conv.1,v 1.3 1999/12/13 22:11:55 hm Exp $
.\"
.\" $FreeBSD$
.\"
.\" last edit-date: [Mon Dec 13 22:54:33 1999]
.\"
.Dd March 15, 1999
.Dt G711CONV 1
.Os
.Sh NAME
.Nm g711conv
.Nd conversions according to G.711
.Sh SYNOPSIS
.Nm
.Op Fl a
.Op Fl u
.Op Fl P
.Op Fl A
.Op Fl R
.Sh DESCRIPTION
The
.Nm
utility
is part of the isdn4bsd package and is used to convert between the A-Law and
u-law formats as specified in ITU G.711.
It is based on a freely available
and freely usable reference implementation done by Sun Microsystems, Inc.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl a
Convert A-law to u-law
.It Fl u
Convert u-law to A-law
.It Fl r
Reverse bits before conversion
.It Fl R
Reverse bits after conversion
.It Fl P
Print the resulting conversion tables (as C-source) to stdout instead of
doing the actual conversion.
.El
.Sh EXAMPLES
The command:
.Bd -literal -offset indent
g711conv -P -a
.Ed
.Pp
prints out the A-law to u-law conversion table as C-source to stdout.
.Pp
The command:
.Bd -literal -offset indent
cat max_headroom.ul | g711conv -u -R > /dev/i4btel0
.Ed
.Pp
converts the u-law coded voice of Max Headroom to A-law, reverses the
bits of the result and moves that to an active isdn4bsd telephone connection.
.Sh STANDARDS
A-Law and u-Law conversions are specified in ITU Recommendation G.711.
.Pp
The reference implementation done by Sun Microsystems, Inc.\& is available
from http://www.itu.int/itudoc/itu-t/rec/g/g700-799/refimpl.txt
.Sh AUTHORS
The
.Nm
utility and this manpage were written by
.An Hellmuth Michaelis Aq hm@kts.org
based on the G.711 conversion reference code written by Sun Microsystems,
Inc.\& and code contributed to isdn4bsd by Stefan Bethke.