Timeline audio functions
Along with the track management functions covered on page Error! Bookmark not defined., the header area of the timeline is also home to a number of audio controls.
Master playback level
Above the timeline track headers is a master playback level indicator. As you preview your project, it shows the total output from all tracks as currently mixed. The expand icon to the right of the indicator opens a small floating window with separate level indicators for each output channel, and a master gain control to trim the output level up or down uniformly.
Click the icon next to the master playback level indicator to open the Master Volume panel, where you can apply an overall volume gain to the composite audio output of your project.
The audio mixer panel pops out to the right of the track headers when you click its access button in the timeline toolbar. For each timeline track, the panel provides two fader knobs.
Track level: The left knob sets the output level of the track as a whole. Its numeric value is shown in a small pop-up window when the mouse pointer is over the knob. The default value of 0dB (which you can restore with a double-click on the knob) means that no overall change is applied to the original volume of the clips on the track. Clicking on the small window opens an edit field where you can enter the desired level. You can also set it by dragging horizontally within the small window.
Clip level: The other knob sets the level of the current clip at the scrubber position. If no clip is currently selected on the track, this second knob is unavailable. The volume contour of a clip can be controlled with keyframes, as discussed immediately below. When keyframing is in use, the clip level knob causes new keyframes to be created or existing ones to be repositioned.
When its access button above the timeline (L) is clicked, the audio mixer panel pops out to the right (R). Each track has two knobs. The first adjusts the level of the track’s overall audio output, the second controls the levels of the current clip. It can be keyframed for moment by moment level control. The third icon on each track opens the Panner.
An audio clip’s level can be varied at will using keyframing, which allows you to create a volume envelope that reflects the dynamic changes you want within the clip. The envelope appears as a green line on the clip; the keyframes are represented by small, square ‘control handles’ along the line. On playback, the clip volume tracks the envelope line as it moves smoothly from one keyframed level to the next.
If there are no keyframes on a clip, the volume contour is a horizontal line representing the default clip volume. To add a keyframe, make sure the volume keyframe editing button on the timeline toolbar is selected, then click on the volume contour of the clip. Alternatively, you can position the scrubber to the desired keyframe location, then simply click the clip level knob; this second method works whether or not the keyframe editing button is lit. In either case, a control handle should appear on the clip. From now on, each change to the clip volume either creates a new keyframe, if there is not one at the current position, or updates the value of one that is already present.
Editing volume keyframes with the mouse
To allow keyframe editing with the mouse, activate the volume keyframe editing button in the group of buttons at the right-hand end of the timeline toolbar. Now when you position the mouse pointer over the green volume contour on an audio clip, you will see that the contour responds by highlighting in white.
To activate clip volume keyframe editing, click the button in the right-hand group on the timeline toolbar.
A number of mouse-based keyframe editing functions are now available. Before taking on any serious keyframe editing, take a few minutes to familiarize yourself with the commands in this set. They enable you to manipulate keyframes quickly without having to repetitiously move to a chosen keyframe and operate the clip level knob.
The default style of editing operations for volume keyframes favors maintaining sections of constant clip level rather than continuously wandering up and down along ‘ramps’ in the contour line. In cases where this does not produce the editing result you desire, try again while holding the Alt key. This turns off any automatic adjustments that might otherwise be made.
Insert a new keyframe by clicking the contour line.
Instantly create a keyframed fade by Ctrl-clicking the contour line. This inserts both a new keyframe at the point you clicked and a second one with the volume set to zero. If you clicked in the first half of the clip, the second keyframe is added at the start to create a fade-in; if you clicked in the second half of the clip, a fade-out is created by placing the second keyframe at the end.
Create abrupt level changes by dragging horizontal sections between neighboring keyframes up or down. This produces vertical steps in the volume contour.
Reposition swells and fades by dragging ‘ramps’ (rising or falling sections of the contour line) laterally within the clip.
Reposition control handles in two dimensions to any allowed point between their immediate neighbors (or the ends of the clip). You can simultaneously change both the time index of the keyframe and the clip volume that will take effect when playback reaches it.
The arrows in this illustration show the uses of the mouse in keyframe editing. An individual control point can be dragged in all directions. Ramps and flat sections are respectively limited to horizontal and vertical movement only.
Delete a keyframe by dragging it onto another keyframes or by moving it vertically away from the contour.
Set a linear fade-in or fade-out by dragging either of the upper corners of the clip horizontally toward the center. Notice before you start that the unfolded corner of the clip becomes slightly dog-eared when the mouse hovers over it. The corner can now be dragged further into the clip, creating a fade. The wider you make the ‘folded-over’ area, the longer will be the duration of the fade.
Fade durations can be edited with the mouse as shown here. You can also click on the folded-over area to open a small dialog box for editing the duration numerically.
Edit an existing fade by positioning the mouse over the vertical line descending from the inward corner of the ‘fold’. Make sure the bidirectional arrow pointer is displayed, then drag the edge as desired.
The context menu for control points on the volume contour provides the commands Add keyframe, Delete keyframe and Delete all keyframes. (Either the first or the second of these commands will be grayed, since only one of them can apply at a time.)
This tool lets you regulate the apparent location of the sound source in relation to a listener within a ‘surround’ listening field. Like the clip volume tool it works with keyframes assigned to the clip, and so is active only when the timeline scrubber is positioned on an audio clip or a video clip with synchronous audio. The contour line for panning changes is drawn in blue.
In the Audio Mixer, the third icon in each track gives access to the Panner, where you can control the positioning of the track’s audio output in a two-dimensional ‘surround’ listening space.
For the purposes of timeline editing, all panning occurs in surround mode, so you only have to deal with a single version of the Panner controls. The surround-panned clips can be mixed down to other output configurations after editing of the project has been completed. This lets you work with a single set of panning decisions for all formats you might eventually produce.
Changes made with this tool apply to the current clip only. They stay with the clip even if you move or copy it to another track.
To open the Panner, click its access button in the track header mixer panel. This button is grayed if there is no clip on the track at the scrubber position. The sound source is denoted by a blue spot on a two-dimensional grid. The listener is situated in the center, facing forward.
The dropdown list at the top of the Panner window provides three methods for distributing the sound across the set of six surround speakers.
5.1 is the best general purpose setting for natural sound reproduction. Use it for general atmospheric sounds, such as barking dogs, or cars passing by. The five main speakers are represented by icons in the work area. The sixth, the LFE (low-frequency effects) speaker, is too low-pitched to provide positional cues. Its level in the surround mix is controlled by a slider beneath the work area.
Center channel off is the preferred setting for an immersive music track.
Dialog mode combines the center speaker with the two at the rear. This combination is suitable for dialog involving multiple speakers.
Positioning the clip audio using the Panner in Dialog mode. Note that the icons for the front corner speakers are translucent, indicating that they are not used in this mode. As adjusted here, the audio for the track will be heard coming from the listener’s right.
The main body of the Panner window schematically depicts a listening area with a typical arrangement of loudspeakers. The cross icon in the center of the area indicates the position of the listener.
A blue control point sets the position of the sound source. The speaker symbols at the edge of the work area show your typical surround 5.1 speaker arrangement, with the screen at the top.
If you want to control the sound source position in one dimension, horizontal or vertical, use the slider at the bottom or right of the work area respectively.
LFE channel: Surround supports a special subwoofer channel (the ‘.1’ in ‘5.1’) that allows you to boost or cut the lowest frequencies for special effects. Control the LFE enhancement with the slider under the work area. Since the ear is unable to pinpoint the location of these low-frequency sounds, the LFE is not assigned to a spatial position.
Keyframe buttons: The keyframe buttons at the bottom of the panel allow you to add, remove and navigate between keyframes. The Add symbol automatically switches to Delete if you are positioned on an existing keyframe’s position.