Title:        radio
Version:      2.0.2
Submitted:    Apr 15 1993
Author:       guido.van.rossum@cwi.nl (Guido van Rossum)
Submittor:    guido.van.rossum@cwi.nl (Guido van Rossum)
Description:  UDP broadcast/receive utilities for audio data

This is Radio version 2.0, patchlevel 2 (a.k.a. 2.0.2).

If you have a local area network full of workstations with audio
capabilities and at least one FM/AM radio or other audio source, you can
broadcast the audio over the network, and let other users listen to it.

This software works for Sun Sparcs running SunOS 4.0 or 4.1, for SGI Indigo
or Personal IRIS 4D/30 or 4D/35 workstations running SGI IRIX 4.0 or 3.3.2,
and for NeXT workstations (running version 2.1).  At CWI, versions of it
have been in continuous use on a mix of Sun and SGI system types for almost
two years; version 1.0 (patchlevel 4) was last tested on a NeXT.  (I've
heard that the program doesn't work on NeXT 3.1; if you fix it please send
me the changes!)

Man pages for "radio" and "broadcast" are provided.

The implementation continuously transmits UDP broadcast packets of 1400
bytes each (i.e. less than six per second), which contain the data in U-LAW
format (8000 samples/second, 1 byte/sample, logarithmically encoded).  On a
typical ethernet, this uses about 1 percent of the net available bandwith.
Some loss of UDP packets is tolerated by the receiving program (this is
heard as short interruptions of the sound).  Every now and then, a short
"station call" packet is transmitted as well, for the benefit of advanced
listening programs.

It is possible to use multiple transmission stations (each identified by a
different UDP port), and to transmit to multiple connected subnets
simultaneously (as long as the gateways let UDP broadcast packets through).
For reasons you don't want to know, you can only have one broadcasting and
one radio process per host, except on the SGI there may be multiple radio
processes.

If you have Motif, you may be interested in the "tuner" program X(version
1.3) by Jack Jansen.  This is a window-based interface that shows the
different broadcasting stations at your site and lets you tune your radio
process to the station of your choice.  It will be posted to comp.sources.x
around the same time as radio 2.0; you can also ftp it from site ftp.cwi.nl
[192.16.184.180], file /pub/tuner1.3.tar.Z.

If you missed a part of the posting of radio, you can ftp the whole
source from ftp.cwi.nl [192.16.184.180], file /pub/radio2.0.tar.Z.

        Guido van Rossum
        CWI, dept. CST
        Kruislaan 413
        X1098 SJ  Amsterdam
        The Netherlands

        E-mail (Internet)  :  Guido.van.Rossum@cwi.nl (guido@cwi.nl)

The "libst" U-LAW conversion library is written and copyrighted by Jef
Poskanzer.