This page describes the ViewStation's NetAudio
client manual page.
NetAudio Audio Client Manual Page
This is the man page for NetAudio. More extensive man pages are
available in the /HDSware/hds-fx/contrib/Netaudio directory.
NAME
NetAudio - a portable, network-transparent audio system
SYNOPSIS
The NetAudio service is a network-transparent system for
playing, recording, and manipulating audio data over a network. It uses
the client/server model to separate application code from the software
drivers needed to control specific audio input and output devices.
DESCRIPTION
The NetAudio service provides applications with the ability to
send and receive audio data such as voice, sound effects, and music in
a network environment. A audio server inside the desktop terminal or
personal computer controls the various input and output devices in
response to messages sent from client programs running on other hosts.
A variety of utility programs are provided that can be used to
play or record audio using shell scripts or command-line procedures.
More ambitious applications can communicate directly with the audio
server using a C-language pro gramming library.
The NetAudio service supports a variety of the common formats
used to store sound data. Audio inputs and outputs can run at a any of
a range of sampling rates. The audio server automatically converts all
data to the designed format or rate.
Streams of data from multiple inputs can be mixed together and
directed to any attached output device. Sounds that are used many times
can be stored in the server so that they do not need to be transmitted
over the network each time they are played. Furthermore, inputs can be
hooked directly to outputs (for example, a CD player can be connected
to a set of speakers) so that data can be played with out requiring any
client intervention or network traffic.
AUDIO SERVER NAMES
Each audio server has a name that is used by applications in
establishing a connection. The format of the name depends upon the type
of network being used.
In TCP/IP environments, audio server
names look like: tcp/hostname:portnum
where hostname is the name or numeric IP address of the
desktop machine to be contacted and portnum is the port number on which
the server is listening. If the ``tcp/'' prefix is not given, 8000 is
automatically added to portnum so that the audio server name is
compatible with the X Window System display name.
In DECnet environments, audio server names look like:
decnet/nodename::num
where nodename is the name or numeric DECnet address of the
desktop machine to be contacted and num is the DECnet task AUDIO$num.
If the ``decnet/'' prefix is omitted, it is automatically added so that
the audio server name is compatible with the X Window System display
name.
Most audio utilities accept a command line argument -audio
servername for specifying the audio server to be contacted. %
auinfo -audio tcp/unit:8000
If no server is specified on the command line, the AUDIOSERVER
environment variable is checked to see if a name has been stored there.
Otherwise, the DISPLAY environment variable used by X Window System
applications is checked and the corresponding audio server is used.
SAMPLE PROGRAMS
Several sample programs that use the NetAudio service are
provided:
auplay
This program simply plays the files listed on its command line.
It is typically used from shell scripts, command-line procedures, or
other programs that just need to ``dump'' sound data to the audio
server.
audemo
This program allows the user to select and play pre-recorded sound
files or to record new sound files. It provides a simple control panel
for dynamically changing the volume while a sound is being played and
for aborting a sound.
audial
This program generates North American telephone touch tones
correspond to a given string. audial can also recognize touch tones and
produce the corresponding string.
autool
This program is compatible with the Sun audiotool program and
is typically used to play prerecorded sound files. Unlike auplay it
provides a graphical interface to allow the user to replay or cancel
the data.
auinfo
This program lists information describing the capabilities of
an audio server.
auctl
This program can be used to change various device parameters.
auscope
This program is an audio protocol filter that can be used to
view the network packets being sent between an application and an audio
server.
aupanel
This program provides an X-based window-oriented interface allowing
the user to adjust the attributes of the devices provided by the
NetAudio service.
auedit
This program provides an X-based window-oriented interface allowing
the user to edit audio files.
auconvert
This program allows the user to perform various conversion
operations on sound files.
AUDIO FILES
The audio programming library and utility programs can be used
to read and write files in any of the following file formats:
Sun/NeXT
These files typically have a `.au' or `.snd' extension. They
are usually produced by Sun or NeXT workstations.
Creative Labs
These files typically have a `.voc' extension. They are usually
produced by by Soundblaster audio cards on IBM PC compatible computers.
Microsoft WAVE
These files typically have a `.wav' extension. They are usually
produced by IBM PC compatible computers.
AIFF
These files typically have a `.aiff' or `.aif' extension. They
are usually produced by SGI workstations or Apple computers.
Due to the nature of the file formats, only the Sun/NeXT file
format can be piped through standard input and/or standard output. The
convention for specifying standard input or standard output is to use a
hyphen ("-") as the file name.
PROGRAMMING
Application developers may create their own audio clients using
the NetAudio programming library.
ENVIRONMENT VARIABLES
The following environment variables are used by NetAudio
programs:
AUDIOSERVER
This specifies the name of default audio server to contact if no
name is explicitly given on the command line.
DISPLAY This specifies the name of an X Window System
display that should be assumed to also have a corresponding NetAudio
server.
SEE ALSO
auctl(1), audemo(1), audial(1), auinfo(1), auplay(1),
auscope(1), autool(1)
COPYRIGHT
The following copyright and permission notice applies to all
files in the NCDaudio application programming libraries and example
programs provided in source form by Network Computing Devices:
Copyright 1993 Network Computing Devices, Inc.
Permission to use, copy, modify, distribute, and sell this software
and its documentation for any purpose is hereby granted without fee,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name Network Computing Devices,
Inc. not be used in advertising or publicity pertaining to distribution
of this software without specific, written prior permission.
THIS SOFTWARE IS PROVIDED `AS-IS'. NETWORK COMPUTING DEVICES,
INC., DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
WITHOUT LIMITATION ALL IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE, OR NONINFRINGEMENT. IN NO EVENT SHALL NETWORK
COMPUTING DEVICES, INC., BE LIABLE FOR ANY DAMAGES WHATSOEVER,
INCLUDING SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, INCLUDING LOSS
OF USE, DATA, OR PROFITS, EVEN IF ADVISED OF THE POSSIBILITY THEREOF,
AND REGARDLESS OF WHETHER IN AN ACTION IN CONTRACT, TORT OR NEGLIGENCE,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.
TRADEMARKS NCD, NCDaudio, NCD Display Station, and NCDware are all
trademarks of Network Computing Devices, Inc.
X Window System is a trademark of the Massachusetts Institute of
Technology.
AUTHORS
Greg Renda, Jim Fulton, David Lemke
NetAudio Last change: 1994/02/14
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