> ## Documentation Index
> Fetch the complete documentation index at: https://docs.videngineer.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Sound layer

> Music segments, an SFX catalog, voice tone, and stems — the audio design mapped scene by scene.

The Sound layer answers: **how is the audio built?** Rather than a flat list of timestamps, the analysis maps sound design onto the video's scene timeline — for each scene: what music is playing, which sound effects fire, and what the voice is doing. It mirrors how an editor lays out a timeline: video, voice, SFX, music.

<Frame caption="The Sound tab on a live teardown — the mood strip over the waveform, plus music segmented where it actually changes.">
  <img src="https://mintcdn.com/videngineer/xzKDutij2z2tdFvi/images/sound-layer.png?fit=max&auto=format&n=xzKDutij2z2tdFvi&q=85&s=3fed030448da0da0e705aab9cb139444" alt="Sound layer showing a waveform with mood bands (tense to uplifting) and music segments with genre, mood, and BPM" width="1540" height="1100" data-path="images/sound-layer.png" />
</Frame>

*Live example: [Coinbase — 'Break The Cycle' teardown](https://videngineer.com/teardowns/cinematic/coinbase-break-the-cycle-manifesto-teardown/), Sound tab — 4 music moods, one BPM spine at 110.*

## Field reference

### `per_scene`

One entry per scene row, in assembly order:

| Field                                      | What it holds                                                                                                                                                                                                                                                                               |
| ------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `scene_index` / `start` / `end`            | Which scene and its time window                                                                                                                                                                                                                                                             |
| `music.present` / `music.mood`             | Whether music plays and its mood — `tense`, `uplifting`, `dramatic`, `playful`, `dark`, `neutral`, `sad`, `epic`, `mysterious`, `energetic`, or `none`                                                                                                                                      |
| `music.genre`                              | Specific — "cinematic-orchestral", "lo-fi hip-hop", "ambient-pad", "synthwave"…                                                                                                                                                                                                             |
| `music.bpm_estimate` / `music.instruments` | Tempo and the 2–4 instruments or synths heard                                                                                                                                                                                                                                               |
| `music.role`                               | `bed` \| `lead` \| `stinger` \| `transition` \| `silence`                                                                                                                                                                                                                                   |
| `sfx[]`                                    | Each effect: `at`, a specific `type` ("riser-buildup", "sub-drop", "tape-stop", "UI-click", "cash-register-ding"…), `description`, `intensity` (`subtle` \| `medium` \| `punchy`), `purpose` (`transition` \| `emphasis` \| `emotional_beat` \| `comedic` \| `attention_grab` \| `ambient`) |
| `voice.present` / `voice.tone`             | Whether there's voice and its delivery — "energetic-narration", "calm-explainer", "breathy-whisper"…                                                                                                                                                                                        |
| `summary`                                  | The scene's overall audio vibe in one sentence                                                                                                                                                                                                                                              |

### `music_segments`

Consecutive scenes with the same musical mood are merged into continuous bands — this is the "Music · segmented cuts" list on the teardown page. Each segment: `start`, `end`, `mood`, `genre`, `bpm_estimate`, `instruments`, `role` (`bed` | `lead` | `transition` | `drop` | `intro` | `outro`).

### `sound_palette`

The whole video's audio fingerprint:

| Field                                                   | What it tells you                                                       |
| ------------------------------------------------------- | ----------------------------------------------------------------------- |
| `total_sfx_events` / `unique_sfx_types` / `type_counts` | How busy and how varied the SFX layer is                                |
| `dominant_purpose`                                      | What the SFX are mostly *for* — transitions, emphasis, emotional beats… |
| `music_dominance_pct`                                   | How much of the runtime sits under music                                |
| `silence_used_as_tool`                                  | Whether silence is deployed deliberately — a strong signal in ads       |
| `sound_density`                                         | `sparse` \| `moderate` \| `dense`                                       |
| `voice_style`                                           | The dominant voice tone across the video                                |

### `recreation_recipe` and `signature_moves`

`recreation_recipe` is a 3–4 sentence spec you can hand to a sound designer — overall genre and BPM range, the dominant SFX palette, key transition cues, voice-over style. `signature_moves` lists the 2–4 audio techniques that make this video's sound distinctive.

## Stems

On demand, the original audio can be split into separated stems — **vocals / drums / bass / other** — plus two merged logical layers: **music** (drums + bass) and **SFX** (other). The vocals stem also powers the voice-isolation workflow for cloning setups. Stems are stored with the teardown and downloadable from the app.

## What to do with it

* **Brief your music search with `music_segments`, not adjectives.** "Ambient pad, tense, 110 BPM, 0:00–0:37, then uplifting synths to the close" finds the right track in one pass.
* **Copy the SFX *placement*, choose your own sounds.** If every scene transition carries a riser and the product reveal lands on silence, that architecture transfers — the specific samples shouldn't.
* **Check `silence_used_as_tool` before adding more sound.** High-performing ads often earn their loudest moment by going quiet first.

## Related layers

<CardGroup cols={2}>
  <Card title="The Cuts" icon="scissors" href="/layers/cuts">
    The shots these audio scenes are synced to.
  </Card>

  <Card title="Script analysis" icon="chart-line" href="/layers/script-analysis">
    The voice-over element — tone, pace, pauses.
  </Card>

  <Card title="Recreation" icon="wand-magic-sparkles" href="/layers/recreation">
    The visual half of the rebuild recipe.
  </Card>

  <Card title="Scorecard" icon="gauge-high" href="/layers/scorecard">
    Where sound design shows up in the format score.
  </Card>
</CardGroup>