Extra Menu: Scriptables I

The Extra > Scriptables I menu provides commands typically used in scripting, for example via Macros or Python.

These commands were originally written for scripting Audacity, e.g via a Python script that uses mod-script-pipe. The commands though are also present in the menu, available from Macros, and available from within Nyquist using (aud-do "command")

Many of these commands have optional values. Where the dialog shows a checkbox with no label, leaving the box unticked leaves the corresponding value unchanged. When using the same command in scripting, leaving the value out entirely has the same effect.

Select <something>

The Select Time, Select Frequencies and Select Tracks options all are used to select audio. There is also a Select dialog that combines all three.

Many more complex macros and scripting depend on the select command. It is worth spending time to understand the options in this command. It can be useful to leave some of the values unset, for example to leave the selected times unchanged but to modify which tracks are selected.

Select Time  

• Start Time and End Time are times.
  • Normally they are times in seconds as shown by the ruler.
  • However setting Relative To to a value other than 'Project Start' will give other behaviour.

Relative To	Meaning
Project Start	Start and end times are both relative to the ruler, starting at 0.
Project	Start time is relative to the ruler time 0. End time is relative to the end of the project.
Project End	Both times are relative to the end of the project and are measured right to left. Use "Relative To" 'Project End' to select from the end of the track, for example to fade out at the end of the track.
Selection Start	Start and end times are both relative to the start of the selection.
Selection	Start time is relative to the start of the selection. End time is relative to the end of the selection. Use "Relative To" 'Selection' and 'Start Time' =-0.5, 'End Time' =+0.5 to expand the selection by 1 second.
Selection End	Both times are relative to the end of the selection and are measured right to left. Use "Relative To" 'Selection End' and 'Start Time' =0, 'End Time' =0 to collapse the selection to its right boundary.

Select Frequencies  

• High and Low are for spectral selection.
  • They select a frequency range which is relevant in certain effects.

Select Tracks  

• First Track is the number of the first track, starting at 0.
• Track Count is the number of tracks. The default is 1.
  • You can set Track Count to 0 to select no tracks (there can still be a time selection in that case).
  • Very occasionally useful, First Track and Track Count can both use fractional values, like 0.5, which can be used to select a channel of a stereo track.
    • One use of selecting a channel rather than a whole track, is in a script to resize the two channels of a stereo track to different heights.
• The Mode parameter allows arbitrary track selections, e.g adding or removing tracks from the current track selection.

Set Track <Something>

The Set Track Status, Set Track Audio and Set Track Visuals dialogs all set properties of the currently selected tracks. There is also a compound version of the dialog that combines all three.

Set Track Status 

Set Track Audio 

Set Track Visuals 

Sets properties for a track or channel (or both). Setting one channel of a stereo track can lead to interesting results. That's most used when setting relative sizing of the two channels.
SpectralPrefs=1 sets the track to use general preferences, SpectralPrefs=0 per track prefs. When using general preferences, SetPreference can be used to change a preference and so affect display of the track.
Name is used to set the name. It is not used in choosing the track. Scheme is used to set the colorway for spectrograms.

Get Preference  

Gets a single preference setting.

'GetInfo: Preferences' is often more useful. It gets a list of preferences all at once

Set Preference  

Sets a single preference setting. Some settings such as changing the theme require a reload (use Reload=1), but reload takes time and slows down a script.

Set Clip  

Modify a clip by stating the track or channel and a time within it.
Color, clip name and start position can be set.
Try to avoid overlapping clips, as Audacity will allow it, but does not like them.

Set Envelope  

Modify an envelope by specifying a track or channel and a time within it.
You cannot yet delete individual envelope points, but can delete envelopes (that contain the chosen time) using Delete=1.

Set Label  

Modifies an existing label. You must give it the label number.

Set Project  

Sets the project window to a particular location and size. Also sets the Project Rate. Can also change the caption - but that is cosmetic and may be overwritten again later by Audacity.