# Ltx 2.3 Quality · Extend Video API

> Leanann sé físeán ar aghaidh nó siar, le híomhá roghnach eochairfhráma deiridh

Síneann gearrthóg atá ann cheana trí phíosaí nua a ghiniúint faoi threoir `prompt` riachtanach. Is é `extend_direction` `forward` chun leanúint ón deireadh nó `backward` chun tús nua a chruthú. Socraíonn `num_context_frames` (9 go 121) méid forluí na foinse, agus socraíonn `num_frames` (9 go 481) fad na míre. Socraíonn `end_image_url` roghnach an eochairfhráma deiridh, agus coinníonn `match_input_fps` ráta fráma na foinse.

- Model id: `ltx-2.3-quality/extend-video`
- Made by: Lightricks
- Category: Video to Video
- Output: video
- Price per megapixel of your output video: $0.00241 / megapixel of output video (cheapest run $0.003 (3 API credits))
- Run: `POST https://api.doitong.com/v1/run/ltx-2.3-quality/extend-video`
- Quote: `POST https://api.doitong.com/v1/quote/ltx-2.3-quality/extend-video`
- Docs page: https://doitong.com/ga/developers/models/ltx-2.3-quality/extend-video

## Pricing

Price: **$0.00241 / megapixel of output video**. Price per megapixel of your output video: the input files are measured before the run (length, resolution, frame rate). The quote measures the same files and is exactly what the run charges.

The full example input below costs $0.27 = 270 API credits (112 MP output video × $0.002408).

Prices are the upstream price in USD, paid from the API balance in API credits (1000 API credits = 1 USD). `POST https://api.doitong.com/v1/quote/ltx-2.3-quality/extend-video` 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 |
|---|---|---|---|---|---|---|
| `prompt` |  | string | yes |  |  | Leid a shonraíonn leanúint inmhianaithe an fhíseáin. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL a dhíríonn ar an bhfíseán a leathnófar. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Mód leathnaithe físeáin: cruthaíonn 'backward' tús nua, agus leanann 'forward' leis an bhfíseán thar a dheireadh. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Comhaireamh frámaí na breise, faoi réir buiséid giniúna chobhsaí ar thaifeach iolraithe faoi fhrámaí: ag 24 fps, thart ar 20 soicind d’aicme 480p, 11 soicind d’aicme 720p, nó 5 soicind d’aicme 1080p. Filleann iarratais a sháraíonn an buiséad 422; laghdaigh `num_frames` nó roghnaigh taifeach níos lú. Áirítear sa chomhaireamh `num_context_frames` atá ag forluí leis an bhfoinse, mar sin is é an fad breise thart ar (`num_frames` - `num_context_frames`) / `frames_per_second` soicind. |
| `num_context_frames` |  | integer | no | `25` | 9 – 121 | Comhaireamh frámaí foinse iarrtha le haghaidh comhthéacs/forluí na breise, teoranta ag líon na bhfrámaí atá san fhoinse. Déantar an comhaireamh a shlánú anuas chun luí leis an ngreille LTX de 8k+1. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Íomhá eochairfhráma roghnach a shocraíonn an chéad fhráma nua den bhreise agus í á leathnú siar, nó a fráma deiridh agus í á leathnú ar aghaidh. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Neart riochtaithe roghnach an eochairfhráma deiridh: tugann laghdú air níos mó saoirse don tsamhail, agus forfheidhmíonn 1.0 meaitseáil bheacht. |
| `resolution` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Toisí an fhíseáin ginte, ailínithe le hincriminte 32px — mar shampla, déantar 1920x1080 de 1888x1056 — agus athmhéadaítear an fhoinse go dtí na toisí seo don aschur fuaite. Is féidir le síntí cobhsaí a bheith níos faide ag taifigh níos ísle agus níos giorra ag taifigh níos airde. Coinníonn 'auto' toisí agus cóimheas gné na foinse chomh fada agus a cheadaíonn teorainneacha LTX. |
| `match_input_fps` |  | boolean | no | `true` |  | Meaitseáil ráta fráma aschuir leis an bhfoinse nuair atá sé cumasaithe, rud a sháraíonn `frames_per_second`. Slánaítear FPS na foinse go slánuimhir agus cuirtear sa raon tacaithe é. |
| `frames_per_second` |  | number | no | `24` | 1 – 60 | Ráta fráma físeáin aschuir, tomhaiste ina fhrámaí sa soicind. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Neart riochtaithe comhthéacs na foinse: ceadaíonn laghdú air níos mó saoirse don tsamhail. Ag 1.0, fanann na frámaí forluiteacha faoi ghlas don fhoinse, rud a fhágann go bhfuil an t-aistriú gan stró. |
| `num_inference_steps` |  | integer | no | `15` | 8 – 30 | Socraigh cé mhéad céim tátail atá le rith, suas le 30; má fhágtar gan athrú é, úsáidtear 15. |
| `guidance_scale` |  | number | no | `1` | 1 – 20 | Coigeartaigh treoir saor ó aicmitheoir ag úsáid an scála seo; díríonn a thiúnadh réamhshocraithe ar ardchaighdeán agus giniúint thapa araon. |
| `generate_audio` |  | boolean | no | `true` |  | Scorán fuaime na breise: fágann as an mír bhreise ina tost agus coinníonn sé rian fuaime an fhíseáin fhoinseach. Gineann air fuaim don bhreise agus déanann sé traschéimniú léi ag an nasc. |
| `negative_prompt` |  | string | no | `color distortion, overexposure, static, blurry details, subtitles, style, artwork, painting, frame, still, dim overall tone, worst quality, low quality, JPEG compression artifacts, ugly, mutilated, extra fingers, poorly drawn hands, poorly drawn face, deformed, disfigured, malformed limbs, fused fingers, motionless frame, cluttered background, three legs, crowded background, walking backwards` |  | Leid dhiúltach a shonraíonn cad ba cheart don ghiniúint a sheachaint. |
| `seed` |  | integer \| null | no |  |  | Síol a fhágann giniúint in-atáirgthe. Má shocraítear é go None, roghnaítear síol go randamach. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Rialaíonn sé an bhfuil leathnú na leide cumasaithe. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Rialaíonn sé an bhfuil seiceáil sábháilteachta cumasaithe. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Réamhshocrú cáilíochta a chuirtear i bhfeidhm ar an bhfíseán aschuir. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Mód scríofa an fhíseáin a bheidh mar thoradh air. |

File parameters (`video`, `end_image`) 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",
  "video": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
}
```

A fuller example:

```json
{
  "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
  "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
}
```

## 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.com/v1/run/ltx-2.3-quality/extend-video?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",
    "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
  }'

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

### JavaScript

```javascript
const API = "https://api.doitong.com/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/ltx-2.3-quality/extend-video?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",
    "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
  }),
});
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.com/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",
    "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4",
}

# Run the model; wait up to 20 s for the finished result in the same call
r = requests.post(API + "/run/ltx-2.3-quality/extend-video", 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.com/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": "ltx-2.3-quality/extend-video",
      "input": {
        "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
        "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
      },
      "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": "ltx-2.3-quality/extend-video",
  "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": 270,
    "usd": "0.27",
    "charged": 270,
    "refunded": 0
  },
  "input": {
    "prompt": "A red fox trots through fresh snow at sunrise, soft golden light, shallow depth of field",
    "video_url": "https://content.doitong.com/video/showcase/v3/gen_fox_cartoon.mp4"
  },
  "output": {
    "video": {
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp4",
      "content_type": "video/mp4",
      "file_name": "0-output.mp4",
      "file_size": 1843200
    },
    "seed": 42,
    "prompt": "string"
  },
  "outputs": [
    {
      "type": "video",
      "url": "https://content.doitong.com/dev-api/2026/10/20/req_8k2m4q7x1z9c3v5b6n0p2r4t/0-output.mp4",
      "content_type": "video/mp4",
      "file_size": 1843200,
      "width": 1280,
      "height": 720,
      "duration": 5,
      "stored": true
    }
  ],
  "error": null,
  "metrics": {
    "inference_seconds": 6.8
  },
  "urls": {
    "self": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t",
    "cancel": "https://api.doitong.com/v1/requests/req_8k2m4q7x1z9c3v5b6n0p2r4t/cancel"
  }
}
```

### Output fields (`output`)

| Field | Type | Description |
|---|---|---|
| `video` | object {url, content_type, file_name, file_size} | An físeán a tháirg an tsamhail. |
| `seed` | integer | An síol iarbhír a chuirtear i bhfeidhm le linn giniúna. |
| `prompt` | string | Leid giniúna, lena n-áirítear aon leathnú a cuireadh i bhfeidhm roimh úsáid. |

## Related models

- [Ltx 2.3 Quality · Text to Video](https://doitong.com/developers/models/ltx-2.3-quality/text-to-video.md) (`ltx-2.3-quality/text-to-video`): $0.00241 / megapixel of output video
- [Ltx 2.3 Quality · Text to Video · LoRA](https://doitong.com/developers/models/ltx-2.3-quality/text-to-video/lora.md) (`ltx-2.3-quality/text-to-video/lora`): $0.00271 / megapixel of output video
- [Ltx 2.3 Quality · Image to Video](https://doitong.com/developers/models/ltx-2.3-quality/image-to-video.md) (`ltx-2.3-quality/image-to-video`): $0.00241 / megapixel of output video
- [Ltx 2.3 Quality · Image to Video · LoRA](https://doitong.com/developers/models/ltx-2.3-quality/image-to-video/lora.md) (`ltx-2.3-quality/image-to-video/lora`): $0.00271 / megapixel of output video
- [Ltx 2.3 Quality · Ingredient](https://doitong.com/developers/models/ltx-2.3-quality/ingredient.md) (`ltx-2.3-quality/ingredient`): $0.00241 / megapixel of output video
- [Ltx 2.3 Quality · Clean Plate](https://doitong.com/developers/models/ltx-2.3-quality/clean-plate.md) (`ltx-2.3-quality/clean-plate`): $0.00241 / megapixel of output video
- [Ltx 2.3 Quality · Colorization](https://doitong.com/developers/models/ltx-2.3-quality/colorization.md) (`ltx-2.3-quality/colorization`): $0.00241 / megapixel of output video
- [Ltx 2.3 Quality · Cross Eyed](https://doitong.com/developers/models/ltx-2.3-quality/cross-eyed.md) (`ltx-2.3-quality/cross-eyed`): $0.00241 / megapixel of output video

## Links

- HTML page: https://doitong.com/developers/models/ltx-2.3-quality/extend-video
- 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=ltx-2.3-quality/extend-video
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/ltx-2.3-quality/extend-video