# Stable Audio 3 Medium Audio Outpainting API

> Stable Audio 3 Medium destilado que prolonga o áudio antes ou depois do clip de origem

Continua uma faixa de `audio_url` orientada por um `prompt`. `extend_seconds_before` e `extend_seconds_after` adicionam, cada um, 0 a 380 segundos de áudio novo. A predefinição é de 8 passos de amostragem. O resultado pode ser mp3, wav, flac, ogg, opus, m4a ou aac.

- Model id: `stable-audio-3/medium/audio-outpainting`
- Made by: Stability AI
- Category: Audio
- Output: audio
- Price: $0.0446 / request (cheapest run $0.045 (45 API credits))
- Run: `POST https://api.doitong.ru/v1/run/stable-audio-3/medium/audio-outpainting`
- Quote: `POST https://api.doitong.ru/v1/quote/stable-audio-3/medium/audio-outpainting`
- Docs page: https://doitong.com/pt-PT/developers/models/stable-audio-3/medium/audio-outpainting

## Pricing

Price: **$0.0446 / request**. Billed once per request.

The full example input below costs $0.045 = 45 API credits (1 request × 44.6 API credits).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.ru/v1/quote/stable-audio-3/medium/audio-outpainting` with the same JSON body returns the exact price for that input; the quote is exactly what a run charges. Invalid input is never charged and failed or canceled requests are refunded automatically.

## Input parameters

Send either the canonical name or the native field name (not both). Canonical names are the same across models.

| Parameter | Canonical name | Type | Required | Default | Allowed values / range | Description |
|---|---|---|---|---|---|---|
| `negative_prompt` |  | string | no | `` |  | Texto que especifica qualidades indesejadas na saída. |
| `num_inference_steps` |  | integer | no | `8` | 1 – 100 | Contagem de iterações de amostragem, com predefinição de 8 porque os checkpoints destilados e pós-treinados já alcançam boa qualidade nesse valor; iterações adicionais oferecem poucos benefícios. |
| `guidance_scale` |  | number | no | `1` | 0 – 25 | Intensidade de orientação sem classificador apenas para checkpoints base; os checkpoints destilados não são afetados. Nos checkpoints aplicáveis, aumentá-la reforça a aderência ao prompt. |
| `seed` |  | integer \| null | no |  |  | Seed do gerador aleatório para resultados reproduzíveis; omiti-la seleciona uma seed aleatória. |
| `enable_prompt_expansion` |  | boolean | no | `false` |  | Expansão do prompt com um LLM quando ativada, adicionando detalhes e melhorando a qualidade do resultado. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Verificação de segurança para conteúdo NSFW. |
| `output_format` |  | enum (string) | no | `mp3` | `mp3`, `wav`, `flac`, `ogg`, `opus`, `m4a`, `aac` | Formato do contentor usado para o áudio resultante. |
| `bitrate` |  | string | no | `192k` |  | Taxa de bits do áudio de saída, ignorada ao usar wav ou flac por serem formatos sem perdas. Para formatos comprimidos como mp3, aac ou opus, forneça um valor no formato '192k' ou '320k'. |
| `prompt` |  | string | yes |  |  | Instruções de texto que descrevem o conteúdo da extensão. |
| `audio_url` | `audio` | string (audio URL) | yes |  |  | Áudio de entrada para extensão. |
| `extend_seconds_before` |  | number | no | `0` | 0 – 380 | Duração, em segundos, do áudio recém-gerado anexado antes da origem. |
| `extend_seconds_after` |  | number | no | `0` | 0 – 380 | Duração, em segundos, do áudio recém-gerado anexado depois da origem. |

File parameters (`audio`) take a public `https://` URL, a `data:` URI up to 10 MB, or the `file_url` of an upload from `POST /files`.

## Example input

Required parameters only:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "audio": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
}
```

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
}
```

## Run it

Set `DOITONG_API_KEY` to a key from https://doitong.com/developers/dashboard#keys. `?wait=20` returns the finished request in the same call when it is ready within 20 seconds; otherwise poll `GET /requests/{id}` (it also accepts `?wait=`), or pass `webhook_url`.

### curl

```bash
# Run the model; wait up to 20 s for the finished result in the same call
curl -X POST "https://api.doitong.ru/v1/run/stable-audio-3/medium/audio-outpainting?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  }'

# Still "queued" or "running"? Poll with the id from the response:
curl "https://api.doitong.ru/v1/requests/REQUEST_ID?wait=20" \
  -H "Authorization: Bearer $DOITONG_API_KEY"
```

### JavaScript

```javascript
const API = "https://api.doitong.ru/v1";
const headers = {
  "Authorization": "Bearer " + process.env.DOITONG_API_KEY,
  "Content-Type": "application/json",
};

// Run the model; wait up to 20 s for the finished result in the same call
let res = await fetch(API + "/run/stable-audio-3/medium/audio-outpainting?wait=20", {
  method: "POST",
  headers,
  body: JSON.stringify({
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  }),
});
let request = await res.json();
if (!res.ok) throw new Error(request.error.code + ": " + request.error.message);

// Not finished yet: long-poll until it is
while (request.status === "queued" || request.status === "running") {
  res = await fetch(API + "/requests/" + request.id + "?wait=20", { headers });
  request = await res.json();
}
if (request.status !== "succeeded") throw new Error(JSON.stringify(request.error));
console.log(request.outputs.map((o) => o.url), request.cost.credits + " API credits ($" + request.cost.usd + ")");
```

### Python

```python
import os
import requests

API = "https://api.doitong.ru/v1"
headers = {"Authorization": "Bearer " + os.environ["DOITONG_API_KEY"]}

payload = {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/stable-audio-3/medium/audio-outpainting", params={"wait": 20}, json=payload, headers=headers)
request = r.json()
if not r.ok:
    raise RuntimeError(request["error"]["code"] + ": " + request["error"]["message"])

# Not finished yet: long-poll until it is
while request["status"] in ("queued", "running"):
    request = requests.get(API + "/requests/" + request["id"], params={"wait": 20}, headers=headers).json()
if request["status"] != "succeeded":
    raise RuntimeError(request["error"])
print([o["url"] for o in request["outputs"]], request["cost"]["credits"], "API credits", "$" + request["cost"]["usd"])
```

### MCP

The MCP server at `https://api.doitong.ru/v1/mcp` exposes the tools `search_models`, `get_model`, `quote`, `run`, `get_request`, `cancel_request`, `list_requests`, `create_upload` and `get_account`. A `run` call for this model:

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "run",
    "arguments": {
      "model_id": "stable-audio-3/medium/audio-outpainting",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
        "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
      },
      "wait_seconds": 20
    }
  }
}
```

## Response

Every call returns a request object. `status` is one of `queued`, `running`, `succeeded`, `failed`, `canceled`. `outputs` lists the generated files with URLs on our storage (kept forever, or 7 days with `?storage=temporary`; `storage` says which); `output` is the model's own result object with the same URLs.

```json
{
  "id": "req_8k2m4q7x1z9c3v5b6n0p2r4t",
  "object": "request",
  "model": "stable-audio-3/medium/audio-outpainting",
  "status": "succeeded",
  "created_at": "2026-10-20T12:00:00Z",
  "started_at": "2026-10-20T12:00:02Z",
  "completed_at": "2026-10-20T12:00:09Z",
  "queue_position": null,
  "cost": {
    "credits": 45,
    "usd": "0.045",
    "charged": 45,
    "refunded": 0
  },
  "input": {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "audio_url": "https://content.doitong.com/audio/showcase/v3/tools/dub_es.mp3"
  },
  "output": {
    "audio": {
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp3",
      "content_type": "audio/mpeg",
      "file_name": "0-output.mp3",
      "file_size": 1843200
    },
    "seed": 42,
    "prompt": "string"
  },
  "outputs": [
    {
      "type": "audio",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp3",
      "content_type": "audio/mpeg",
      "file_size": 1843200,
      "duration": 12,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.ru/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.ru/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `audio` | object {url, content_type, file_name, file_size} | Clipe de áudio produzido pela geração. |
| `seed` | integer | Seed que controlou a aleatoriedade durante a geração. |
| `prompt` | string | Prompt utilizado para gerar a saída. |

## Related models

- [Stable Audio 3 Small Music Audio Inpainting](https://doitong.com/developers/models/stable-audio-3/small/music/audio-inpainting.md) (`stable-audio-3/small/music/audio-inpainting`): $0.026 / request
- [Stable Audio 3 Small Music Audio Outpainting](https://doitong.com/developers/models/stable-audio-3/small/music/audio-outpainting.md) (`stable-audio-3/small/music/audio-outpainting`): $0.0265 / request
- [Stable Audio 3 Small Music Base Audio Inpainting](https://doitong.com/developers/models/stable-audio-3/small/music/base/audio-inpainting.md) (`stable-audio-3/small/music/base/audio-inpainting`): $0.0333 / request
- [Stable Audio 3 Small Music Base Audio Outpainting](https://doitong.com/developers/models/stable-audio-3/small/music/base/audio-outpainting.md) (`stable-audio-3/small/music/base/audio-outpainting`): $0.0339 / request
- [Stable Audio 3 Small Music Base Audio to Audio](https://doitong.com/developers/models/stable-audio-3/small/music/base/audio-to-audio.md) (`stable-audio-3/small/music/base/audio-to-audio`): $0.032 / request
- [Stable Audio 3 Small Music Text to Audio](https://doitong.com/developers/models/stable-audio-3/small/music/text-to-audio.md) (`stable-audio-3/small/music/text-to-audio`): $0.0217 / request
- [Stable Audio 3 · Small · Music · Audio to Audio](https://doitong.com/developers/models/stable-audio-3/small/music/audio-to-audio.md) (`stable-audio-3/small/music/audio-to-audio`): $0.0248 / request
- [Stable Audio 3 · Small · Music · Base · Text to Audio](https://doitong.com/developers/models/stable-audio-3/small/music/base/text-to-audio.md) (`stable-audio-3/small/music/base/text-to-audio`): $0.0281 / request

## Links

- HTML page: https://doitong.com/developers/models/stable-audio-3/medium/audio-outpainting
- All models and guides for AI agents: https://doitong.com/developers/llms.txt
- OpenAPI 3.1 with this model's typed request body: https://doitong.com/developers/openapi.json?model=stable-audio-3/medium/audio-outpainting
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.ru/v1/models/stable-audio-3/medium/audio-outpainting