# Ltx 2.3 Quality · Extend Video API

> Joatká video ovddas dahje maŋos, vejolaš maŋemus-kľuččarámmágovain

Guhkáha dálá klippa buvttadettiin ođđa videomateriála, man čuovvu geatnegahtton `prompt`. `extend_direction` lea `forward` joatkkit loahpas dahje `backward` ráhkadit ođđa álggu. `num_context_frames` (9 to 121) mearrida man ollu gáldu gokčá, ja `num_frames` (9 to 481) mearrida oasi guhkkodaga. Eaktodáhtolaš `end_image_url` giddida loahpalaš váldogova, ja `match_input_fps` doalahá gáldu govvaráhta.

- 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/se/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 |  |  | Bivdda mii meroštallá video háliduvvon joatkka. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL mii čujuha videoi mii galgá guhkkiduvvot. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Video-guhkkidanvuohki: 'backward' ráhkada ođđa álggu, 'forward' joatká video loahpa badjel. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Guhkkidan-rámma-lohku, mii lea ráddjejuvvon stabiila-ráhkadeami bušeahtain resolušuvdna gearddu rámmaid: 24 fps:s sullii 20 sekunda 480p-klássas, 11 sekunda 720p-klássas dahje 5 sekunda 1080p-klássas. Bušeahta badjel mannat jearaldagat máhccet 422; unnidit `num_frames` dahje vállje unnit resolušuvdna. Lohku sisttisdoallá `num_context_frames` rámmaid mat leat gáldos overlappet, nu ahte lasihuvvon guhkkodat lea sullii (`num_frames` - `num_context_frames`) / `frames_per_second` sekunda. |
| `num_context_frames` |  | integer | no | `25` | 9 – 121 | Gáldo-rámmaid lohku mii bivdojuvvo guhkkidan kontekstii/overlappii, ja mii lea ráddjejuvvon gáldo rámmaid lohku mielde. Lohku sirdá vuollebeliin heivvolaš LTX-gridii 8k+1. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Lassi vuođđorámma-govva mii mearrida guhkkideami ođđa vuosttaš rámma backward-vuohkái dahje loahppa rámma forward-vuohkái. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Lassi loahppa-vuođđorámma kondišunerema nanusvuohta: unnideapmi addá modeallii eanet friddjavuođa, muhto 1.0 gáibida dárkilis ovttastahttima. |
| `resolution` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Ráhkaduvvon video-dimenšuvnnat, heivehuvvon 32px ceahkiide — ovdamearkka dihte 1920x1080 šaddá 1888x1056 — ja gáldu skálerejuvvo dáidda dimenšuvnnaide seagujuvvon boađusa várás. Stabiila guhkkideamit sáhttet leat guhkit vuollelis resolušuvnnain ja oaneheabbat alla resolušuvnnain. 'auto' doalahá gáldo dimenšuvnnaid ja govva-gaskavuora nu guhkás go LTX ráddjehusat diktet. |
| `match_input_fps` |  | boolean | no | `true` |  | Boađus-rámmafrekeansa mii aktiverejuvvon heivehuvvo gáldui ja buhttá `frames_per_second`. Gáldo FPS sirdá olleslogui ja ráddjejuvvo doarjjujuvvon gaskaohkui. |
| `frames_per_second` |  | number | no | `24` | 1 – 60 | Boađus-video rámmafrekeansa, meroštallojuvvon rámmaiguin sekunddas. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Gáldo-konteksta kondišunerema nanusvuohta: unnideapmi addá eanet friddjavuođa modeallii. 1.0:s overlappet rámat bissot gáldui čatnasan, mii dahká johtima seammas. |
| `num_inference_steps` |  | integer | no | `15` | 8 – 30 | Mearrit man galle inference-ceahki čađahat, gitta 30 rádjái; jus dán ii rievdat, geavahuvvo 15. |
| `guidance_scale` |  | number | no | `1` | 1 – 20 | Heive classifier-free guidance dán skálain; dan standárdaheivehus ulbmil lea alla kvalitehta ja jođánis ráhkadeapmi. |
| `generate_audio` |  | boolean | no | `true` |  | Guhkkidan-jietnaga molssaeapmi: apaguvvon lasihuvvon oassi lea jietnagat, muhto gáldo-video jietnaráidu seailluhuvvo. Aktiverejuvvon ráhkada jietnaga guhkkideapmái ja crossfade:a dan gálduin čatnaseami sajis. |
| `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` |  | Negatiiva bivdda mii čilge maid ráhkadeapmi galgá heaittihit. |
| `seed` |  | integer \| null | no |  |  | Sádji, mii dahká ráhkadeami reprodukšuvnnalažžan. None bidjan vállje sádji juhkosiid mielde. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Stivre leago bivdda viiddideapmi anus. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Stivre bealuštaniskkadeami doaibmama. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Kvalitehta-heivehus mii geavahuvvo boađus-videui. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Boađusvideo čájehanvuohki. |

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} | Modealla ráhkadan video. |
| `seed` | integer | Ieš sivaárvu mii geavahuvvo ráhkadeamis. |
| `prompt` | string | Ráhkadanbivdda, maiddái buot lassáneapmi mii lea dahkkon ovdal geavaheami. |

## 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