sfxMaster
Mix all your Voice Over, Sound Effects, and Music from three master sliders — audio layers are auto-categorized by marker comments and wired up in one pass.
Category: effects · Version: 2.0.1 · UI: HEADLESS (no dialog; alert/confirm prompts only)
What it does
sfxMaster turns a composition's scattered audio layers into a centrally mixable session. Select one or more compositions in the Project panel and run it: the script builds a null named "SFX CTRL" holding three Slider Control effects — Voice Over, Sound Effects, and Music — that act as master volume knobs. It then walks every layer in each comp (recursing into precomps), finds all audio-only footage layers, and buckets each one into a category by reading the layer's first marker comment.
Every audio layer gets a Stereo Mixer effect whose Left/Right Level parameters are expression-linked to the matching master slider, so nudging one slider scales every layer in that category at once — "duck the music", "boost the VO", "mute all SFX" without hand-wiring dozens of layers. Because it recurses into nested comps and can process several selected comps in one run, it's a one-shot pass that standardizes audio control across an entire project structure.
Controls & options
Marker-based categorization (the routing surface)
The category is decided by the first marker on each audio layer. The comment is lowercased and substring-matched:
| First marker comment contains | Category slider |
|---|---|
voice over | Voice Over |
music | Music |
| anything else, or no marker at all | Sound Effects |
Example: a marker comment of Voice Over - intro narration routes that layer to the Voice Over slider. Matching is case-insensitive; only the first marker is read — later markers are ignored.
What it builds
| Control | Location | Default | Purpose |
|---|---|---|---|
| Voice Over (Slider Control) | "SFX CTRL" null → Effects | 0 | Master level for voice-over layers |
| Sound Effects (Slider Control) | "SFX CTRL" null → Effects | 0 | Master level for uncategorized/SFX layers |
| Music (Slider Control) | "SFX CTRL" null → Effects | 0 | Master level for music layers |
| Overwrite prompt | confirm dialog | — | Appears only when some layer already has an expression-linked Stereo Mixer; your yes/no applies to every selected comp in one shot |
The Stereo Mixer levels are set equal to the slider value, and they behave as percentages — so raise each slider to 100 for original volume; the sliders start at 0 (silent).
Usage
- Tag audio layers with a layer marker whose comment contains "voice over" or "music" where you want those buckets; leave the rest unmarked to route them to Sound Effects.
- Select one or more compositions in the Project panel (not layers in the Timeline).
- Run sfxMaster.
- If prompted about existing linked Stereo Mixers, choose whether to overwrite them.
- In each processed comp, adjust the Voice Over / Sound Effects / Music sliders on the "SFX CTRL" null to mix. Start by setting them to 100 (unity), then ride them from there.
Notes
- The generated expressions reference the comp and control layer by name:
comp('<comp name>').layer('SFX CTRL').effect('<slider>')('Slider'). Renaming the comp, the "SFX CTRL" null, or the sliders afterward breaks the links. - Precomp layers are wired back to the top-level comp's SFX CTRL, not to a control inside the precomp — one console rules the whole nested structure.
- If a layer already had a linked Stereo Mixer and you decline to overwrite, a second Stereo Mixer is added alongside it, leaving the original's expressions intact.
- An existing layer named "SFX CTRL" is reused as-is; its sliders are not re-created or repaired.
- Everything runs in a single undo group.
Requirements & edge cases
- After Effects CC 2019 or later.
- At least one item selected in the Project panel, and every selected item must be a composition — otherwise the script alerts and stops.
- Only footage layers with no video count as audio (e.g. imported
.wav/.mp3). A video file that also carries audio is skipped entirely — its audio is not wired to the console. - The overwrite decision is one global yes/no for the whole run; there is no per-layer choice.
- Nested comps are walked with unlimited depth; a precomp used in several places is processed once per appearance.
How it works
A single self-invoking main(). It reads app.project.selection, opens the "Apply Stereo Mixer" undo group, and makes two passes over the selected comps. Pass one ensures each comp has an "SFX CTRL" null (comp.layers.addNull() plus three ADBE Slider Control effects renamed Voice Over / Sound Effects / Music) and runs processComp() in check-only mode, OR-accumulating whether any layer anywhere already carries an expression-linked Stereo Mixer — if so, a single confirm() asks about overwriting. Pass two runs processComp() in apply mode with that answer.
processComp() iterates layers 1-based; audio-only footage layers (FootageItem with hasVideo === false) get categorized and wired, precomp layers recurse with the same top-level mainCompName, and everything else is skipped. determineSlider() lowercases the first marker's comment and checks indexOf('voice over') / indexOf('music'), defaulting to Sound Effects. applyStereoMixer() finds the layer's "Stereo Mixer" by display name, adds one when missing (or adds a second when the user declined overwrite), then assigns the slider-reference expression to both Left Level and Right Level.