# Timeline

At the top of the track display area is the timeline display. This consists of a number of rulers, a meter track, a tempo track and the marker display.

The available rulers include:

## Ruler Types

Ruler Type | Description
--- | ---
Frames | this ruler measures audio frames. The number of audio frames per second depends on the sample rate in use.
SMPTE | this ruler displays SMPTE timecode. The SMPTE format (25fps, 30fps, drop frame etc) is selected in the Options Editor option_editor.
Min:Sec | this ruler displays time in minutes+seconds, measured since the start of the session.
BBT | (Bars,Beats,Ticks) this ruler displays positions based on the tempo map.

To show or hide one or more of the rulers, click on the area to the left of their names. A menu will popup that has a check item for each available ruler. Click on the name of the ruler to toggle its visibility.

The tempo and meter tracks display the tempo map for the session. The tempo track contains 1 or more tempo change points, with a default tempo of 120 beats per minute. The meter track contains 1 or more meter change points, with an initial default meter of 4/4.

on a tempo/meter change point to edit it. Click in the tempo/meter track to add a new change point. Click and drag on a change point to move it. on a tempo/meter change point to remove it.

There is more information on using the timeline in editing_basics.