# FFmpeg Loudnorm (assembly)

> Loudnorm sets the loudness of one audio file to a target level (EBU R128). The result is a new audio file, not a video.

Status: roasOS API v1.1. Catalog `model-catalog@2026-10-06.v5`, pricing `customer-pricing@2026-11-05.v15`. The endpoint `POST /v1/assembly/loudnorm` is live. `POST /v1/generations` has no `assembly` type, so this endpoint is the only path to this model.

## Endpoint
POST https://api.roasos.com/v1/assembly/loudnorm
Auth: Authorization: Bearer roasos_sk_… (scope api:write). Idempotency-Key required. quote_only / quote_id / webhook_url as in https://docs.roasos.com/llms.txt.

## Good at
Make a music bed or a voice-over the correct level before you put it under a clip. For a music bed under speech, set `integrated_loudness` to -30. Then use Merge Audio and Video or Compose to put the track onto the clip.

The price is one credit, flat.

## Pricing
Unit: operation. Pricing key: `loudnorm`.

| request | credits |
|---|---|
| `per_operation` | 1 |

Credits come from the roasOS pricing table (`MODEL_COSTS`) through the catalog. No other field changes the price.

## Modes
- `loudnorm`
Provider endpoints: `fal-ai/ffmpeg-api/loudnorm`.

## Request fields
| field | type | required | default | rule |
|---|---|---|---|---|
| `audio_url` | string | yes | — | https URL; ≤ 4,096 characters |
| `integrated_loudness` | number | no | — | -70–-5 |
| `loudness_range` | number | no | — | 1–20 |
| `quote_id` | string | no | — | UUID |
| `quote_only` | boolean | no | `false` | — |
| `true_peak` | number | no | — | -9–0 |
| `wait_timeout_seconds` | integer | no | `0` | 0–60 |
| `webhook_url` | string | no | — | https URL; ≤ 4,096 characters |

The schema is strict: a field that is not in this table returns `400 unsupported_option`. Field names are the roasOS role names, one name per role across every family.

## Media
- `audio_url` — the driving audio track

| role | items | max size | content types | duration |
|---|---|---|---|---|
| `audio_url` | ≤ 1 | 15 MB | `audio/mp3`, `audio/mpeg`, `audio/wav`, `audio/wave`, `audio/x-wav` | — |

- Refused: `avatar_id`, `elements`, `product_id`, `product_images`, `references`, `reference_images`, `image_url`, `end_image_url`, `scene_id`, `scene_image`, `video_urls`, `video_url`, `audio_urls`, `voice_id`. A refused role returns `400 unsupported_option`.
- Every URL must be an immutable object on `https://cdn.roasos.com/…` that your workspace owns; any other URL is `400 reference_media_not_workspace_owned`. Upload with `POST /v1/uploads` (direct POST of the bytes to `put_url`, or a `source_url` import), then use the returned CDN URL.

## Prompt
None. This operation takes no prompt.

`audio_url` is required. It must be an audio file that your workspace owns on cdn.roasos.com. The three targets are optional. If you do not send a target, the provider default applies:

- `integrated_loudness` is the target loudness in LUFS, from -70 to -5. The default is -18.
- `true_peak` is the maximum true peak in dBTP, from -9 to 0. The default is -0.1.
- `loudness_range` is the target loudness range in LU, from 1 to 20. The default is 7.

The result is a WAV file.

## Not exposed
- `offset`: not accepted by this public endpoint.
- `linear`: not accepted by this public endpoint.
- `dual_mono`: not accepted by this public endpoint.
- `print_summary`: not accepted by this public endpoint.
- `measured_i`: not accepted by this public endpoint.
- `measured_lra`: not accepted by this public endpoint.
- `measured_tp`: not accepted by this public endpoint.
- `measured_thresh`: not accepted by this public endpoint.

## Result
Result kind `audio`. Always present: `url`. Present when the run produces it: `timestamps`.
```json
{ "data": { "id": "gen_…", "kind": "audio", "model": "loudnorm", "status": "completed", "result": {"timestamps":[{}],"url":"https://cdn.roasos.com/workspaces/ws_01/result"} } }
```
Files live on `https://cdn.roasos.com` and are immutable; a result URL can be a media input to the next call. Poll `GET /v1/jobs/{id}/status` → `{ id, status, updated_at }`, then `GET /v1/jobs/{id}/result` (`409 run_not_completed` until the job is `completed`, `failed` or `canceled`). Statuses: `queued → processing → completed | failed | canceled`.

## Example
```bash
# 1. quote — nothing is spent
curl -X POST https://api.roasos.com/v1/assembly/loudnorm \
  -H "Authorization: Bearer roasos_sk_live_…" \
  -H "Idempotency-Key: 0f1c9e2a-loudnorm-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_only":true,"audio_url":"https://cdn.roasos.com/workspaces/ws_01/uploads/audio_url.mp3"}'
# → 200 { "data": { "kind": "quote", "quote_id": "q_7Hk…", "credits": 1, "expires_at": "…", "confirmation": { "model": "loudnorm", "example": "per_operation" } } }

# 2. run — the same body and the same Idempotency-Key, quote_id instead of quote_only
curl -X POST https://api.roasos.com/v1/assembly/loudnorm \
  -H "Authorization: Bearer roasos_sk_live_…" \
  -H "Idempotency-Key: 0f1c9e2a-loudnorm-0001" \
  -H "Content-Type: application/json" \
  -d '{"quote_id":"q_7Hk…","audio_url":"https://cdn.roasos.com/workspaces/ws_01/uploads/audio_url.mp3"}'
# → 201 { "data": { "id": "gen_…", "kind": "audio", "model": "loudnorm", "status": "queued", "credits_reserved": 1, "links": { "status": "/v1/jobs/gen_…/status", "result": "/v1/jobs/gen_…/result" } } }

# 3. poll
curl https://api.roasos.com/v1/jobs/gen_…/status -H "Authorization: Bearer roasos_sk_live_…"
curl https://api.roasos.com/v1/jobs/gen_…/result -H "Authorization: Bearer roasos_sk_live_…"
```

## Today
The endpoint is `POST /v1/assembly/loudnorm`.

It is live.

## See also
https://docs.roasos.com/models/assembly/loudnorm · https://api.roasos.com/v1/catalog/assembly/loudnorm · fal-ai/ffmpeg-api/loudnorm