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Manual page for SOUNDTOOL(6)

soundtool - audio play/record tool

SYNOPSIS

soundtool

AVAILABILITY

This command is only available with the Demos installation option. Refer to [a manual with the abbreviation INSTALL] for information on how to install optional software.

DESCRIPTION

soundtool is a SunView demonstration program that allows recording, playing, and simple editing of audio data. The display consists of six regions: a play/record control panel, a function control panel, an oscilloscope, a display control panel, a waveform display panel, and a pop-up audio status panel.

Play/Record Control Panel

Play/Stop: Clicking this button plays the currently selected region of data. While data is playing this button becomes a Stop button. If audio output is busy when Play is started, this button displays Waiting. When the device is available, the button switches to Stop and audio output begins. Clicking on the Waiting button resets the tool to the idle state.
Record/Stop: Clicking this button starts the recording of data from the audio input port that is wired to the 8-pin mini-DIN connector on the back of SPARCstation 1 systems. While recording is in progress, this button becomes a Stop button. If audio input is busy when Record is selected, an alert pops up and the tool resets to the idle state. A maximum of 5 minutes may be recorded at a time.
Pause: Clicking this button while playing or recording suspends the current operation. The button becomes a Resume button that may be selected to continue the suspended operation.
Describe: Clicking this button brings up the ``Audio Status Panel''. If the panel was already visible, clicking this button removes it.
Quit: Clicking this button exits soundtool.
Play Volume: This slider adjusts the playback volume. Volume levels between 0 and 100 may be selected, where 0 represents infinite attenuation and 100 is maximum gain.
Record Volume: This slider adjusts the recording level in the range 0 to 100.
Output To: This selector switches the audio output port between the built-in speaker and the external headphone jack.
Looping: When Looping is disabled, the current data region (that is, the data between the two markers in the waveform display) is played once. If Looping is enabled, the selected data plays endlessly until the Stop button is pressed.

Function Control Panel

Load: Clicking Load reads in the audio file specified by the Directory and File fields. If the named file does not contain a valid audio header, the raw data is copied into the buffer and an alert is displayed. Clicking the Store button at that point rewrites the file with the proper audio file header.
: Arbitrarily large audio files may be loaded. However, system swap space resources may be depleted (one minute of SPARCstation 1 audio data consumes roughly .5 Mbyte of swap space).
Store: Clicking Store writes the selected data region into the file specified by the Directory and File fields. If the named file exists, an alert will request confirmation of the operation.
Append: Clicking Append appends the selected data region to the file specified by the Directory and File fields. The named file must contain a valid audio file header.
Directory: The Directory field specifies a directory path in which to look for audio files.
File: The File field designates the file to be loaded from, stored to, or appended to. Holding down the right mouse button on this field presents a menu of audio files in the currently designated directory. All files that contain a valid audio file header, or whose names have the suffix .au or .snd, are listed.

Oscilloscope

When the program is in the idle state and the cursor is in the waveform display panel, the oscilloscope acts as a magnifying glass, displaying the region of the audio waveform that is currently under the cursor. When the program is playing or recording, the oscilloscope displays the data that is currently being transferred. Note: there is a small time lag in the display of recorded data, due to the fact that the audio device driver buffers input data and delivers it to the application in discrete segments.

Display Control Panel

Zoom: The Zoom slider adjusts the compression factor used in the display of the waveform. The upper compression limit is chosen so that the entire waveform fits in the waveform display panel. The lower limit is restricted by the ability to manipulate large scrolling regions in SunView. Adjustment of the Zoom slider ordinarily results in data compression or expansion around the center of the currently displayed waveform. If the waveform display contains one or both data selection markers, an attempt is made to keep at least a portion of the selected data region in the window.
: The magnified waveform presented in the oscilloscope display is unaffected by the Zoom value. However, cursor movement over the waveform reflects the current compression; that is, lower Zoom values result in finer granularity of mouse movement.

Waveform Display Panel

: The waveform display shows all or part of the current waveform, depending on the current Zoom value. Scrolling of the waveform may be achieved either by using the scrollbar or by dragging the waveform to the right or left while holding the middle mouse button down. Note: scrolling is disabled when the entire waveform is being displayed (that is, when the Zoom value is at its maximum).
: In some cases, it is desirable to identify a subset of the waveform. For instance, the Play, Store, and Append functions operate on a selected region, rather than the entire waveform. The currently selected region of interest is delimited by dashed vertical lines. A new region may be selected by clicking the left or right mouse button and dragging it across the desired region of interest. Alternatively, a single click on the left or right mouse buttons adjusts the start or end points.

Audio Status Panel

: This panel is displayed (or removed) when the Describe button is pressed. It contains fields that describe the data in the buffer.
Sample Rate: This field displays the sampling frequency, in samples per second.
Channels: This field denotes the number of interleaved channels of audio data.
Precision: This field identifies the encoding precision, in bits per sample.
Encoding: This field displays the encoding format.
Total Length: This field shows the length of the entire data buffer, in the form hh:mm:ss.dd.
Selection: This field identifies the start and end times of the currently selected region of interest.
Info String: When an audio file is loaded, the first 80 characters of the information field of the audio header are displayed in this field. This string may be edited, though the new information is only written out when the Store operation is performed.

BUGS

Currently, soundtool is capable of displaying only 8-bit µ-law encoded data. This restriction should be removed.

Audio files should be mapped in order to reduce the swap space requirements. The limit on recording length should also be removed.

SunView scrollbars operate on canvases whose virtual size is given by a short integer (that is, 16 bits). This ridiculous constraint is the reason for the lower limit on zooming. Because of this, the accuracy of start and end point selection is reduced when the data buffer is large.

Region selections made over the waveform display panel work best when the click and drag paradigm is used. Adjusting the start or end points by a single click is susceptible to error; that is, if the mouse moves slightly between the button down and up events, the result is a very small selection.

WARNINGS

This program is furnished on an as is basis as a demonstration of audio applications programming.