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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.
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