Animate sound with actions

An action can change a clip’s sound as it plays: a pan sweeps across, an EQ band rises, the isolated voice fades in. What you hear in the preview is what an export writes.

Menu: Clip ▸ Add Action
Keys: ⌥⌘K
Where: Clip tab ▸ Sound, with an action selected
Agent tools: add_actionset_action_end

Animate a sound setting

Select the clip, move the playhead to where the change should start, and add an action with ⌥⌘K. The new action lasts 1 second and is already selected.
Open the Sound tab.
Set the controls to how they should be when the action ends.
To make the change take longer, drag the end of the action’s band.

To come back to an action later, select it first. Otherwise the Sound tab changes the clip’s own settings.

For the level alone, it’s quicker to ⌥-click the volume line.

What an action can animate

With an action selected, these write that action’s end state instead of the clip’s own settings:

Volume, Mute and the fade lengths
Pan and Mix to mono
Channels
the EQ and Hum
Amount in Voice Isolation
Noise Reduction
the Gate, the Leveller and the De-esser
the Compressor and the Limiter

Numbers glide, switches jump

Numbers move smoothly across the action’s span. Switches hold their start value and change at the action’s end, with no glide, as at a cut between two clips.

These are the switches:

Mute, Mix to mono and EQ Bypass
turning a section or an EQ slot on or off
Channels
a pass filter’s slope
Hum’s mains and harmonics
the Leveller’s Response

Unticking a section or an EQ slot with an action selected turns it off at the action’s end.

A number only glides while its section is on at both ends of the action. A section an action turns on arrives at its end values when the action ends. Voice Isolation’s Amount and Noise Reduction’s Remove noise are the exceptions. Each is one amount, and 0 is its off, so it glides up from 0 or down to it.

What can’t be animated

These always change the clip’s own settings, even with an action selected:

Ducking
Keep pitch
the fade shapes, In shape and Out shape
the Voice Effect
a nest clip’s Mix to mono

A row like this shows ⊘ in front of its label while an action is selected. See What an action can animate.

A voice effect is made from the clip’s own Voice Isolation Amount, not an animated one.

Normalize, Enhance Voice and Match Audio also write the clip’s own settings with an action selected. The Normalize button carries a small boxed “clip” tag to show this.

Processing turned on by an action

A clip gets whatever preparation its sound needs when an action asks for it, even if the clip’s own setting is off:

The isolated voice is made when an action raises Amount, on a clip whose own Voice Isolation is off.
The Gate, the Leveller and the De-esser measure the clip’s loudness when an action turns them on.
A Limiter or Noise Reduction turned on by an action is set up for the clip’s whole track, as one set on the clip itself is, so the sound’s timing doesn’t shift at the moment it comes on.

With an agent

set_audio only reaches a clip’s own settings. To animate, an agent uses add_action and then set_action_end. See Tools: animation.