audemo - Network Audio System record and play demo
audemo [
-audio servername] [
-toolkitoption ...] [
directory]
audemo provides an X-based window-oriented user interface to the Network
Audio System service. It allows the user to play pre-recorded sound files,
record new sound files and to manipulate Network Audio System buckets.
audemo uses the X Toolkit Intrinsics and the Athena Widget Set. For more
information, see the Athena Widget Set documentation.
audemo starts out with a single window divided into several areas:
- o
- A collection of command buttons.
- o
- A left and right level meter.
- o
- A volume indicator and control slider.
- o
- An information window.
- o
- An editable field containing the directory to be searched
for sound files.
- o
- An editable field containing a list of sound files to
search for.
- o
- A window containing the list of sound files that may be
selected for playing or loading into buckets.
To play a sound file you must first select it from the list of files in the file
window. You can control which files are listed in this window by editing the
Directory and/or
Template fields and clicking on the
Rescan button. To select a file, single-click on the filename. This
will highlight the filename and display information about the file in the
information window. The information displayed includes:
- Filename
- The full pathname of the file.
- File Format
- The file format of the audio file.
- Data Format
- The encoding format of the audio data.
- Tracks
- The number of tracks of audio data.
- Frequency
- The frequency at which the audio data was sampled.
- Duration
- The duration of the audio data in seconds.
- Text
- Any text information stored in the file.
Once the file has been selected, you can start it playing by clicking on the
Play command button. A shortcut for playing a file is to double-click
on the file name. This will select the file and start it playing. When a file
is playing, the
Play command button is highlighted. To stop the playing
of a file, click on the highlighted
Play button. To enable the left and
right level meters, click on the
Meter button before starting to play
the file. To disable the left and right level meters, click again on the
highlighted
Meter button. To adjust the volume level, use the volume
slider.
audemo can record sound files in any supported file and data format. To
record a sound file you must first bring up the record window by clicking on
the
Record command button. This will bring up a window containing the
following fields and controls:
- Filename
- The name of the file you wish to create. Unless a path is
specified here, the file will be created in the current directory.
- File Format
- A menu of file formats.
- Data Format
- A menu of data formats. Note that each file format does not
necessarily support all of the data formats listed.
- Max Duration
- See RECORDING TO A BUCKET.
- Read Only
- See RECORDING TO A BUCKET.
- Frequency
- The sampling rate (in hertz) for the recording. Higher
sampling rates yield better quality sound but take up more disk and memory
space. Common sampling rates are 8000 (good for voice annotations), 11000,
22000, and 44000.
- Mic(rophone)
- This button tells the audio server if you've got a
microphone attached to the audio input jack. Clicking this button will
highlight it and cause the audio server to boost the input gain to a level
suitable for recording with a microphone.
- Comment
- Text (such as a description) you wish to put into the audio
file.
- Gain
- This slider is used to adjust the recording gain
level.
- Record
- This button starts or stops the recording.
- Monitor
- This button enables or disables monitoring.
- New Bucket
- See RECORDING TO A BUCKET.
- Dismiss
- This button stops recording and monitoring and closes the
record window.
Once you have selected the filename, file and data formats, frequency, mic
level, comment and gain, you are ready to record. To listen in on the audio
that will be recorded you can click on the
Monitor button. This will
direct all the audio received from the audio input jack to be played on the
speaker. When you're ready to record, click on the
Record button. All
the audio received from the audio input jack will now be recorded into the
file. The recording will continue until you click on the
Record button
again or click on the
Dismiss button.
NOTE: Audio data can
accumulate very rapidly, especially at high sampling rates, resulting in large
files.
The Network Audio System service provides the capability to create server
resident sound objects called
buckets.
audemo allows the user to
create
buckets, record into them, play from them, load them with data
from a file and dump their contents into a file. Note that buckets created by
audemo are destroyed when
audemo is terminated. These options
are available when you bring up the buckets window by clicking on the
Buckets button in the main window. The buckets windows is divided into
two areas:
- o
- A collection of command buttons.
- o
- A table of buckets currently accessible. This table
contains the following columns:
- Description
- The text description.
- Duration
- The duration of the audio data in seconds.
- Tracks
- The number of tracks of audio data.
- Frequency
- The frequency at which the audio data was sampled.
- Format
- A code letter indicating the encoding format of the audio
data. A key to the format code letters can be displayed by clicking on the
Format Key button.
- Access
- A combination of code letters indicating the access mode of
the bucket. A key to the access code letters can be displayed by clicking
on the Access Key button.
To create a bucket from from an audio data file, select the filename from the
list of files in the file window then click the
Load button in the
buckets window. The first line of the buckets table should now contain the
information about the newly created bucket.
To play a bucket, select the bucket you wish to play by clicking on it's
information in the buckets table. The entry you click on should be
highlighted. Then click on the
Play button in the buckets window. A
shortcut for playing from a bucket is to double-click on the bucket
information. This will select the bucket and start playing from it. To stop
the playing of a bucket, click on the highlighted
Play button in the
buckets window. The level meters and volume level can be controlled in the
same way as when playing from a file.
To record into a new bucket, click on the
Record button in the buckets
window. This will bring up the record window. This record window is the same
as the one used for recording to files. Instead of specifying a filename, in
the
Max Duration field, enter the maximum duration (in seconds) of data
that the bucket is to hold. Clicking on the
Read Only button will
prevent other applications from writing into or destroying the bucket. The
frequency, mic level, format and comment are used in the same way as when
recording to files. Once all of the fields are set appropriately, click the
New Buckett button. This will create a new bucket according to the
specifications given. The first line of the buckets table should now contain
the information about the newly created bucket. To begin recording into the
bucket, select the bucket by clicking on it's information in the buckets
table. Then click the
Record button in the record window. All the audio
received from the audio input jack will now be recorded into the bucket. The
recording will continue until you click on the
Record button again,
click on the
Dismiss or the bucket is filled. The
Gain slider
and the
Monitor button operate the same as when recording to a file.
To save a bucket to a file, first select the bucket by clicking on its
information in the buckets table. Then click on the
Save button in the
buckets window. A dialog box will pop up prompting you for the name of the
file in which to save the bucket data, and the file format. The data format
used will be that of the bucket. Note that each file format may only support
selected data formats. If no path is given in the filename, the file will be
created in the current directory. Clicking on
Ok or pressing the
RETURN key will cause the file to be created and the data from the
bucket to be written to the file.
To delete a bucket, first select the bucket by clicking on it's information in
the buckets table. Then click on the
Delete button in the buckets
window. If the
audemo has the appropriate access permissions for the
bucket, the bucket will be deleted and it's information will be removed from
the bucket table.
Clicking on the
Quit button will cause
audemo to exit, stopping
any playing or recording operations and destroying any buckets that were
created.
-
-audio servername
- This option specifies the Network Audio System server to
which audemo should connect.
- directory
- The directory name that audemo will use to build the
list of selectable file names. When directory is not specified on
the command line, the current working directory is used.
In the following example, in a
TCP/IP network,
mcxterm is the name
of the desktop machine running the audio server. The default port is
8000 and sound files are located in
~/snd:
- audemo -audio tcp/mcxterm:8000 ~/snd
In the following example, the shortened form of the audio server name is used
and sound files from the current working directory will be used:
- audemo -audio mcxterm:0
In addition to the standard toolkit environment variables, the following
environment variables are used by
audemo:
- AUDIOSERVER
- This variable specifies the default audio server to contact
if -audio is not specified on the command line. If this variable is
not set and the -audio is not specified on the command line,
audemo will attempt to connect to the audio server running on the X
Window System display.
Warning: audemo is the xterm of the Network Audio System. It was written to test
features as the Network Audio System was being developed. It was also the
author's first Xt program. Consequently, it's pretty ugly and should be
completely re-written from scratch.
nas(1),
X(1)
Copyright 1993, 1994 Network Computing Devices, Inc.
Greg Renda, Network Computing Devices, Inc.