Label Tracks

From Audacity Manual

Creating Labels

Suppose that you have a recording of an interview and you want to annotate the questions and answers so you can easily jump directly to a particular question or answer later on. Initially, you may have something like the image below. Without any annotation it's almost impossible to tell them apart just looking at the waveform.

Here, we select the first question with the mouse (below). This may require listening to the audio several times to determine the exact boundaries of the selection.

Now click on Tracks > Add Label at Selection, or type its keyboard shortcut ( CTRL + B on Windows/Linux or CMND+B on the Mac). This creates a new label track and a blank label outlining the current selection (below).

The cursor is automatically positioned inside the label, so just type the name of the label and then press Enter. Pressing Enter then allows you to use any current keyboard shortcuts normally, so you could press spacebar to listen to the selection again if you wished. In the image below we've typed Question 1.

After this question comes the answer from the person being interviewed. We'll select this one by starting from the right side of the answer and dragging to the left. Note that a vertical yellow guide appears when we get to the edge of the first label, making it easy to line up the two labels (below). It's common for the next label to start exactly where the previous one ends, but it's not necessary.

Once again, click on Tracks > Add Label at Selection to create the next label, then type its name and press Enter. Then in the following image, we've added even more labels.

And here is a complete label track with several labels

Selecting a label

Whenever you click on the title of a label inside the label track, it selects the label and also selects that range of audio in all audio tracks. It also lets you edit the name of the label.

Press TAB to move from one label to the next, and SHIFT+TAB to move backwards.

Deleting labels

There are three ways to delete labels:

• Click on the label's title to select it, then press the Backspace key on your keyboard until the title is gone. Once the title is empty, press Enter or just press Backspace again to delete the label. Currently, it's also possible to delete a label by selecting a region over the label (be careful not to drag the selection up into the audio track as well), then Edit > Silence Audio. Both these methods will let any labels further to right retain their current position.

• You can also select a region extending over a number of labels then use Edit > Cut (which copies the label to the clipboard) or Edit > Delete. Note however that this method currently causes any labels to right to move backwards by the amount of the deleted selection region.

• Another way to delete labels is to just remove the label track entirely and start again. Click in the track and then choose Remove Tracks from the Tracks menu, or alternatively click in the close box in the upper-left corner of that track.

Like everything in Audacity, any edits to label tracks can be undone.

Editing labels

Changing the length and position of labels with the mouse

You can move a label by clicking and dragging on a circle handle. You can change the length of a label by clicking and dragging on a triangle handle.

Holding SHIFT while dragging reverses this behaviour, so that dragging a circle handle changes the length of the label, and dragging a triangle handle moves the label. For example, this lets you resize a label by SHIFT-dragging a circle handle, then release SHIFT to move the resized label without having to move the mouse pointer to the triangle handle.

In the case where two labels meet, you can adjust the junction point where they meet by clicking and dragging on its circle handle.

Moving a point label

You can move a point label by clicking and dragging on the circle handle:

Before	After

Expanding a point label

You can expand a point label into a region label by clicking and dragging on either of the triangle handles:

Before	After

Moving and resizing a region label

You can move a region label by clicking and dragging on either of the circle handles:

Before	After

You can change the length of a region label by clicking and dragging on one of the triangle handles:

Before	After

Adjusting the junction point where two labels meet

You can adjust the junction point where two labels meet by clicking and dragging on its circle handle:

Before	After

Using cut, copy and paste

There is also a handy feature whereby you can select an area of text in a label, then right-click (control-click on a Mac) and cut or copy that text. This allows you to click in another label, right-click or control-click, then paste that text in. So in our example you could select and copy "Question" and then paste it into the appropriate labels without having to type that word every time. The example below shows one way this can be used.

Click in a label, then select the label text. Note the difference in appearance of selected label text (as shown below - the text is highlighted separately from the box) versus a selected label (where the entire label box is highlighted). Right-click (or control-click on Mac) in the label:

Now select the range of audio corresponding to the second question and click on Track > Add Label at Selection. Right click in the new label:

The text "Question" will be pasted into the label, and all you have to type is "2" to complete the label.

You can also cut and paste labels using Edit > Cut and Edit > Paste, but you have to make sure you don't select any audio, or you will end up pasting audio where you probably didn't intend.

In this image the label was selected by clicking in it, then the audio track was unselected by shift-clicking in the track panel of the audio track. The label was then cut to the clipboard with Edit > Cut.

After clicking in a different spot on the label track, the label can be pasted to that spot using Edit > Paste.

Editing multiple labels at once

Sometimes it's useful to edit multiple labels at once using a tabular view, similar to editing a spreadsheet. To do this, click on Tracks > Edit Labels, which brings up a dialog box showing all of your labels:

Use the arrow keys to move between cells. Handy buttons in the dialog let you insert or delete labels, or import and export labels to a file (see the section on importing and exporting below).

Adding labels while playing or recording

One of the easiest ways to create labels is while you're playing or recording. There's a separate command for this, Add Label at Playback Position, also in the Tracks menu, or you can press its keyboard shortcut, CTRL + M. Note that despite the name of the command, it doesn't only work while playing an existing track; you can use it while recording a new one, too.

Note the difference between this and the previous command, Add Label at Selection. While playing or recording, both commands are useful. Use Add Label at Playback Position to mark the exact spot you're listening to, or use Add Label at Selection if you want to make selections to label with the mouse while you're simultaneously listening (either playing or recording).

Importing and Exporting labels

Labels are saved whenever you create an Audacity project. Sometimes it may be useful to use these labels in another program, for example if somebody wanted to know the time where each piece of an interview starts or stops. Audacity exports labels in a very simple tab-delimited plain text format that looks like this:

0.285874 -> 6.098646 -> Question 1
6.098646 -> 13.054914 -> Answer 1
13.054914 -> 20.916450 -> Question 2
20.916450 -> 28.777986 -> Answer 2

The first column has the start time in seconds, the second column has the end time, and the third column has the name of the label. Start time and end time are identical if the label marks the cursor position rather than a selection region. Values are separated by tab characters (shown as -> in the above). The exported file is called "labels.txt" by default. It can be opened by any text editor, or by a spreadsheet program.

You can export labels using the Edit Labels dialog box, or by selecting Export Labels... from the File menu. Labels can be imported using the Edit Labels dialog box, or by selecting Import > Labels... from the File menu.