# Ltx 2.3 Quality · Extend Video API

> Ikompli vidjo 'l quddiem jew lura, b'immaġni fakultattiva tal-frejm ewlieni finali

Estendi klipp eżistenti billi tiġġenera filmati ġodda ggwidati minn `prompt` meħtieġ. `extend_direction` huwa `forward` biex tkompli mit-tmiem jew `backward` biex toħloq bidu ġdid. `num_context_frames` (9 sa 121) jistabbilixxi kemm mis-sors jikkoinċidi, filwaqt li `num_frames` (9 sa 481) jistabbilixxi t-tul tas-segment. `end_image_url` mhux obbligatorju jiffissa l-aħħar keyframe, u `match_input_fps` iżomm ir-rata tal-frejms tas-sors.

- 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/mt/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 |  |  | Prompt li jispeċifika l-kontinwazzjoni mixtieqa tal-vidjo. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL li jindika l-vidjo li se jiġi estiż. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Modalità tal-estensjoni tal-vidjo: 'backward' toħloq bidu ġdid, filwaqt li 'forward' tkompli l-vidjo lil hinn mit-tmiem tiegħu. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Għadd ta' frejms tal-estensjoni, soġġett għal baġit ta' ġenerazzjoni stabbli fuq ir-riżoluzzjoni mmultiplikata bil-frejms: f'24 fps, madwar 20 sekonda għal klassi 480p, 11-il sekonda għal klassi 720p, jew 5 sekondi għal klassi 1080p. It-talbiet li jaqbżu l-baġit jirritornaw 422; naqqas `num_frames` jew agħżel riżoluzzjoni iżgħar. L-għadd jinkludi `num_context_frames` li jikkoinċidu mas-sors, għalhekk it-tul miżjud huwa madwar (`num_frames` - `num_context_frames`) / `frames_per_second` sekondi. |
| `num_context_frames` |  | integer | no | `25` | 9 – 121 | Għadd ta' frejms tas-sors mitlub għall-kuntest/duplikazzjoni tal-estensjoni, limitat min-numru ta' frejms li fih is-sors. L-għadd jitqarreb 'l isfel biex joqgħod mal-grid LTX ta' 8k+1. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Immaġni fakultattiva tal-keyframe li tissettja l-ewwel frejm ġdid tal-estensjoni meta tiġi estiża backward jew l-aħħar frejm tagħha meta tiġi estiża forward. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Saħħa fakultattiva tal-kundizzjonament tal-keyframe tat-tmiem: it-tnaqqis tagħha jagħti aktar libertà lill-mudell, filwaqt li 1.0 jinforza qbil eżatt. |
| `resolution` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Dimensjonijiet tal-vidjo ġġenerat, allinjati ma' żidiet ta' 32px—pereżempju, 1920x1080 isir 1888x1056—bis-sors imqassam għal dawn id-dimensjonijiet għall-output magħqud. Estensjonijiet stabbli jistgħu jkunu itwal f'riżoluzzjonijiet aktar baxxi u iqsar f'dawk ogħla. L-għażla ta' 'auto' iżżomm id-dimensjonijiet u l-proporzjon tal-aspett tas-sors sal-limiti ta' LTX. |
| `match_input_fps` |  | boolean | no | `true` |  | Tqabbil tar-rata tal-frejms tal-output mas-sors meta jkun attivat, u jissostitwixxi `frames_per_second`. L-FPS tas-sors jiġi arrotondat għal numru sħiħ u ristrett għall-medda appoġġjata. |
| `frames_per_second` |  | number | no | `24` | 1 – 60 | Rata tal-frejms tal-vidjo tal-output, imkejla fi frejms kull sekonda. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Saħħa tal-kundizzjonament tal-kuntest tas-sors: it-tnaqqis tagħha jippermetti aktar libertà lill-mudell. F'1.0, il-frejms li jikkoinċidu jibqgħu msakkra mas-sors, u jagħmlu t-tranżizzjoni bla qtugħ. |
| `num_inference_steps` |  | integer | no | `15` | 8 – 30 | Issettja kemm passi ta' inference għandhom jitħaddmu, sa 30; jekk tħallih kif inhu jintużaw 15. |
| `guidance_scale` |  | number | no | `1` | 1 – 20 | Aġġusta classifier-free guidance billi tuża din l-iskala; l-irfinar prestabbilit tagħha jimmira għal kwalità għolja u ġenerazzjoni mgħaġġla. |
| `generate_audio` |  | boolean | no | `true` |  | Toggle tal-awdjo tal-estensjoni: mitfi jħalli s-segment miżjud sieket filwaqt li jżomm it-track tal-awdjo tal-vidjo tas-sors. Mixgħul jiġġenera awdjo għall-estensjoni u jgħaqqdu crossfade mas-sors fil-punt tal-għaqda. |
| `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` |  | Prompt negattiv li jispeċifika x'għandha tevita l-ġenerazzjoni. |
| `seed` |  | integer \| null | no |  |  | Seed li jagħmel il-ġenerazzjoni riproduċibbli. L-issettjar tiegħu għal None jagħżel seed b’mod każwali. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Jikkontrolla jekk l-espansjoni tal-prompt hijiex attivata. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Jikkontrolla jekk il-verifika tas-sikurezza hijiex attivata. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Preset tal-kwalità applikat għall-vidjo tal-output. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Modalità tal-kitba għall-vidjo li jirriżulta. |

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} | Vidjo prodott mill-mudell. |
| `seed` | integer | Żerriegħa attwali applikata waqt il-ġenerazzjoni. |
| `prompt` | string | Prompt tal-ġenerazzjoni, inkluża kwalunkwe espansjoni applikata qabel l-użu. |

## 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