Audacity Selection

From Audacity Manual

Special characteristics of audio selection

In a word processor, most operations are performed by selecting a range of text (usually with the mouse), then choosing some option from a toolbar or menu, for example to cut the text, or make it bold. Audacity works much the same way: most operations are performed by selecting audio with the mouse and then applying some operation.

Audacity selections can be more complicated than word processor selections, though. In Audacity, the selection involves a set of selected tracks, and then a range of time within those selected tracks. This is because sometimes you might want to select multiple tracks so that any changes you make apply to all of them, but other times you might want to affect the tracks individually. In either case, you may or may not want the edits to apply to the whole time range of the tracks.

Normally, you select both the tracks and the time range simultaneously, by clicking and dragging. For example, to create the following selection, make sure you're using the Selection tool and click the cursor at 5.0 seconds in the first track, and drag rightwards to 7.0 seconds on the timeline so that the gray selection area extends down into the second track:

Note that the selection area does not extend down to the third track because that track is not selected. Therefore, any operation you perform will now only affect the selected area of the first two tracks.

It's possible to change the selected time range and which tracks are selected independently. To change the selected time range, you have several options:

• Move the mouse cursor to one of the edges of the selection until it changes to a different pointer. Click and drag to change that edge of the selection.
• Shift-click near one of the edges of the selection to extend or contract the selection to the time point you clicked on.
• Use Shift + LeftArrow, Shift + RightArrow, Control + Shift + LeftArrow, and Control + Shift + RightArrow to move the two edges of the selection in either direction.

To change which tracks are selected without affecting the time range, you also have multiple options:

• Shift-click on the Track Panel to left of the waveform to toggle its selection
• Press Shift+UpArrow, Shift+DownArrow, Control+Shift+UpArrow, and Control+Shift+DownArrow to extend or contract the selection up or down tracks.
• Press UpArrow or DownArrow to change the focused track, then press the Enter key to toggle its selection.

Note that it is possible to have a time range selected but no tracks selected. In that case, you will only see the evidence of the selected time range in the timeline.

Audio editing is different from text editing in another way, too. With audio, it usually isn't obvious from the waveform what you want to select, so you really want to listen just to the left and right edges of a selection to make sure you are editing the correct part. But if you are new to audio editing, don't worry. For now, you can just click and drag to create a selection on a single track, and hit spacebar to listen to all of it. Come back here for more help when you start to work on more advanced projects and are having trouble selecting what you want.

Besides clicking and dragging with the mouse, there are several other ways to select audio, some of which will be better for visually impaired users or those who have difficulty with the mouse. Let's look at all the different ways to select audio now.

Selecting using the mouse

The easiest way to select a range of audio is to click and drag. If it's not already chosen, choose the Selection tool from the Tools toolbar, below:

Now click the left mouse button anywhere inside of an audio track, and click and drag to the other edge of your selection, and release. Some tips:

• You can drag from left to right or from right to left, it doesn't matter.
• You can start your selection in one track, and end it in another track, and both tracks (plus the tracks in-between) will all end up selected.
• If you move the mouse past the left or right edge of the window while dragging, Audacity will scroll the window in that direction as long as the mouse button is down.

To extend or contract an existing selection, hold down the Shift key while clicking the mouse. The nearest edge of the selection will jump to the current mouse cursor location. This is really useful if you know exactly what you want to select but it doesn't easily fit on the screen at once:

• Click at one edge of the selection
• Scroll until the other edge is in view
• Shift-click to set the other edge of the selection

You can also extend or contract a selection by positioning the mouse near the edge of a selection, then clicking and dragging. The selected portion of a track with the cursor is changed to a pointing hand, see below:

The cursor changes to a pointing hand when you are near the edge of a selection, so you know when you can click and drag to extend or contract the selection.

The Selection Bar

One handy way to keep track of what you've selected and to make precise modifications is to use the Selection Bar (shown above). For our purposes here, let's concentrate on the main purpose of the bar, the Selection Start and End/Length boxes. By changing the radio button from End to Length, you can display and control the length of the selection instead of the endpoint. Which one is useful for you depends on the circumstances: if you need a clip from a song that's exactly 30 seconds long, you may want to set the length to 30, and then modify the start until you have just what you want. Other times you may know the exact end time but need to figure out where to start, independent of the resulting length.

You can edit the time displayed in the Selection Bar using the mouse and/or keyboard. To change a particular digit, you can just click on it and type a new value, see below.

You can also edit the boxes in the Selection Bar entirely using the keyboard, see below.

In the figure above, the selection is displayed in units of hours, minutes, and seconds. As shown, it doesn't display any more accuracy than that, so it's hard to tell if you have half of a second selected, which can be very important sometimes. That's no problem, because Audacity gives you a plethora of choices of possible ways to display the time in the selection bar. To get these choices, click on the right triangle to the right of each box, or alternatively, right-click anywhere in the box to open the context menu.

The different time formats are listed in the table below. It's okay if most of them don't mean anything to you. Most of them are intended for people using Audacity for very specific purposes, especially editing soundtracks for video, and those people will know which one they want.

Selecting using the keyboard

You can modify the selection entirely using the keyboard. The currently focused track is indicated with a glowing border, as you can see from the track called "Guest" in this image:

To change the focused track, just press the up and down arrow keys. In this image, we pressed down arrow to change focus to the "Bkgnd" track:

Once a track is focused, press ENTER or RETURN to change it from being selected to not selected, or from not selected to selected.

To modify the time range, press the left and right arrow keys in combination with SHIFT + CTRL. If you don't already have a selection, just a cursor, then pressing the left or right arrow keys will move the cursor. If you do have a selection, pressing the left arrow will take you to the beginning of the selection, and the right arrow will take you to the end.

If you hold down Shift while pressing the right arrow, you can extend the selection to the right. Similarly, SHIFT + LEFT extends the selection to the left.

CTRL + SHIFT contracts the selection. CTRL + SHIFT + LEFT contracts the right edge to the left, and CTRL + SHIFT + RIGHT contracts the left edge to the right.

Selecting while audio is playing

Sometimes the easiest way to select an exact portion of audio is to mark the selection boundaries while you're playing audio. To do this, press the '[' key to mark the left edge of the audio, and the ']' key to mark the right edge.

After you've done that, you'll definitely want to listen to the resulting selection to make sure it was right. Press the spacebar to hear just the selection. There are many additional keyboard shortcuts that let you listen to just the beginning or end of a selection - see Playing and Recording for a complete list.

Snap-to Guides

Audacity makes it really easy to make a selection that starts or end at a natural boundary, like the start or end of a track or clip.

1.4 has support for a new type of snapping, in addition to Edit > Snap-to. For the new snapping, when you take the following actions:

• Creating a selection with the mouse
• Modifying the selection boundaries
• Sliding / time-shifting a clip

the selection boundaries or the boundaries of the clip you're time-shifting will snap to the following locations:

• Time 0
• The start or end of any clip, in any track
• The start or end of any label

Whenever snapping is taking place, a yellow vertical line appears to indicate snapping is taking place. If there is more than one logical place to snap to within a couple of pixels, it will not snap anywhere, to err on the side of caution. In that case, zoom in.

In the image below, we're dragging a clip in the "Guest" track leftwards with the mouse. When the clip reaches the right-hand boundary of the clip above it, a bright vertical guide line appears showing the position of the snap boundary through all the tracks. Now that the guide line has appeared, we can release the mouse and the dragged clip will be perfectly aligned with the one above:

A Snap Guide appears (the vertical yellow line) when the selection has snapped to the start or end of an audio clip from any of the tracks.

If there are two boundaries very close to one another and it's not obvious which one is better, Audacity will not snap to either. If you want to snap to one of them, zoom in so that you can clearly position the mouse closer to one than the other.

Track Selection using the mouse

There are two very useful things you can do by clicking in the label area to the left of a track, like this - make sure that you click in a neutral area, not inside one of the buttons or sliders.

Clicking on a track's label area will select the entire track. That's a very easy way to apply an effect to an entire track. If you want to select all tracks, you can alternatively choose Select All from the Edit menu.

There's another handy way to select an entire track or clip: just double-click inside of it.

If you hold down Shift while clicking on a track's label, you can toggle the selection of that track. For example, if you want to select the first and third tracks only, you could choose Select All and then shift-click on the middle track to deselect it while leaving the others selected.

Note that it is possible to have a time range selected but no tracks selected. In that case, you will only see the evidence of the selected time range in the timeline.

Menu commands for selecting

The Edit menu has several commands that are useful for selecting, see below.

Label Tracks

A very useful way to recall particular selections is to label them in a label track. For more information, see Label Tracks.