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, just type the name of the label then press Enter (pressing Enter allows you to use any current keyboard shortcuts normally--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

Alternative Method Using Point Labels

In the example above we used region labels to mark the interview segments. We could just as easily have used point labels.

For example, we could click in the audio track at the beginning of the first question then click on Tracks > Add Label at Selection to create the point label.

Similarly, we could click in the audio track at the beginning of the first answer then click on Tracks > Add Label at Selection to create the second point label.

Either method is equally valid. Region labels have the advantage that clicking in the label text selects the audio spanned by the region label, which may be useful in some situations.

Selecting a label

When you click inside a label to select it, the label is opened so its name can be edited, and the cursor point or region of audio the label corresponds to is restored. The cursor point or region will also be selected in any other currently selected audio tracks.

Use Tab on your keyboard to select forwards to the next label, and SHIFT+Tab to select backwards to the previous label. If no label is selected but the Label Track has focus (shown by the yellow border), Tab will select the first label then cycle forwards through the labels, and SHIFT+Tab will select the last label then cycle backwards through the labels.

Removing labels

• To remove labels without affecting other labels: Single-click in the text of an individual label, then press the <Delete> or <Backspace> key (as appropriate) on your keyboard until the text is removed. Once the label is empty of text, press <Delete> or <Backspace> once more to delete the label. You can also remove one or more labels without affecting other labels by selecting any region extending over (or at least touching) the label edges(s), then choose Edit > Split Cut.

• To remove labels (or regions of label track), affecting the following label(s): You can remove labels or regions between labels by selecting over or between labels, then choose Edit > Cut or Edit > Delete. If you remove part of an area inside a region label, this will reduce the length of the label. Labels following to right of the removed labels will always move backwards according to the length of the removed selection.

  When removing parts of the label track you may often want to remove the corresponding audio too, so that the remaining labels still relate to their original audio. To remove the audio region as well as the label region, either drag the selection upwards to include the audio track or enable Sync-Locked tracks.

You can also remove all labels at once by removing the label track entirely. To do this, click in the track and choose Tracks > Remove Tracks. Alternatively, click the close box in the upper-left corner of the label track.

Like everything in Audacity, any edits to label tracks can be undone by Edit > Undo.

Editing labels

Changing the length and position of labels with the mouse

You can move a label by clicking and dragging its circle handle. You can change the length of a label by clicking and dragging its 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 its circle handle, then release SHIFT to move the resized label without having to move the mouse pointer to its triangle handle.

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

Moving a point label

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

Before	After

Expanding a point label

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

Before	After

Moving and resizing a region label

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

Before	After

You can change the length of a region label by clicking and dragging one of its 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 their shared circle handle:

Before	After

Moving a label when there is a selection

The illustration below shows what happens if you click in a label to select it, press ENTER, then move the label.

Before	After

Contrast this to what happens if you click in a label to select it, then move the label.

Before	After

Using cut, copy and paste

Cutting and Pasting Region Labels

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

In the image below, the label was selected by clicking in it, then the audio track was unselected by shift-clicking in the Track Control Panel of the audio track (this can also be done with the keyboard by Up Arrow then ENTER). The label was then cut to the clipboard with Edit > Cut:

To paste the label at a different point in the audio track, either a) click in the audio track at the point where you would like the label to begin then shift-click in the label track to select it; or b) click in the label track at the point where you would like the label to begin. The label can then be pasted to that spot using Edit > Paste.

Cutting and Pasting Point Labels

You can also cut and paste point labels, but the procedure is tricky. In the image below, the point label is selected for editing as in the above example with a region label, but there is no selected region in the label track.

What happens next depends on the setting of the "Select all audio in project, if none selected" preference in Tracks Preferences:

• If that preference is not selected, Edit > Cut will be disabled and pressing CTRL+X will do nothing.
• If that preference is selected and you do Edit > Cut, all audio and labels in the project will be cut to the clipboard.

To cut and paste a point label to a different location, first select the text of the label as shown below. Note the difference in appearance of selected label text (the text is highlighted separately from the box) versus a selected label (where the entire label box is highlighted).

Do Edit > Cut - the text of the label is cut to the clipboard, leaving a label with no text. Press Delete to delete the label. Click in the new location for the label and do Edit > Paste Text to New Label.

Using the Contextual Menu

There is a handy feature where you can select an area of text in a label then right-click to cut, copy or paste over (if there is text currently in the clipboard) that text. This allows you to click in another label, right-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 in the label:

Now select the range of audio corresponding to the second question and click on Track > Add Label at Selection. Right click (control-click on a Mac) 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.

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).

Labels and Sync-Locked Tracks

Labels can be used with the Sync-Locked Tracks feature to define groups of Sync-Locked tracks. Also, some editing operations will behave differently when Sync-Locked Tracks is enabled, for example cutting a section out of a label track that is part of a Sync-Locked Track Group will also cut audio and labels from any other tracks in the group. See the Sync-Locked Tracks page for more information.

Adding labels while playing or recording

One of the easiest ways to create labels is while you're playing or recording. To do this, use the command Tracks > Add Label at Playback Position or its keyboard shortcut CTRL + M. This command adds a point label at the current Audio Position indicated in Selection Toolbar, so can be used to add a label at the current recording position too.

The Add Label at Selection command for adding a region label can also be used while playing or recording - use the mouse to click and drag the selection region while you are listening to the track.

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.