# LTX-2.3 22B · Extend Video API

> Nastavlja postojeći video prema promptu, s generiranim zvukom i neobaveznom završnom slikom

Prima `video_url` i `prompt` te generira nastavak od `num_frames` kadrova (9 do 481). Neobavezni `end_image_url` određuje gdje završava proširenje. `match_input_fps` zadržava broj sličica izvora, `generate_audio` dodaje zvuk, a `video_size` prema zadanim postavkama je auto. Izlaz može biti mp4, webm, mov ili GIF.

- Model id: `ltx-2.3-22b/extend-video`
- Made by: Lightricks
- Category: Video to Video
- Output: video
- Price per megapixel of your output video: $0.00161 / megapixel of output video (cheapest run $0.002 (2 API credits))
- Run: `POST https://api.doitong.com/v1/run/ltx-2.3-22b/extend-video`
- Quote: `POST https://api.doitong.com/v1/quote/ltx-2.3-22b/extend-video`
- Docs page: https://doitong.com/hr/developers/models/ltx-2.3-22b/extend-video

## Pricing

Price: **$0.00161 / 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 $0.18 = 180 API credits (112 MP output video × $0.001605).

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-2.3-22b/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 koji se upotrebljava kao osnova za generiranje videa. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL videa koji će se produljiti. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Navedite URL slike završne sličice da biste definirali završetak produljenog videa. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Broj sličica generiranog izlaza. |
| `video_size` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Dimenzije generiranog videa. |
| `generate_audio` |  | boolean | no | `true` |  | Određuje uključuje li videozapis generirani audio. |
| `use_multiscale` |  | boolean | no | `true` |  | Prekidač za višestruko skalno generiranje radi bolje koherentnosti i detalja. Uz True preliminarni manji video usmjerava drugo generiranje čija veličina doseže ili premašuje tražene dimenzije. |
| `match_input_fps` |  | boolean | no | `true` |  | Nadjačavanje izlazne brzine izmjene sličica koje, kada je omogućeno, zadani ciljni FPS zamjenjuje FPS-om izvornog videa. |
| `fps` |  | number | no | `24` | 1 – 60 | Broj izlaznih sličica u sekundi. |
| `num_inference_steps` |  | integer | no | `40` | 8 – 50 | Broj izvedenih koraka inferencije. |
| `video_cfg_scale` |  | number | no | `3` | 1 – 20 | Postavka usmjeravanja videa: povećajte je za veću dosljednost i fokus generiranog sadržaja. Koristi usmjeravanje bez klasifikatora (CFG). |
| `video_stg_scale` |  | number | no | `0` | 0 – 20 | Upravljanje dosljednošću i fokusom videa putem skale prostorno-vremenskog usmjeravanja (STG); povećajte postavku za jačanje obiju značajki. |
| `video_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Prilagodba ponovnog skaliranja videa za uravnoteživanje usmjeravanja bez klasifikatora i prostorno-vremenskog usmjeravanja kao omjera. |
| `video_modality_scale` |  | number | no | `3` | 0 – 10 | Prilagodba modaliteta videa za uravnoteživanje doprinosa videa i audija kao omjera. |
| `audio_cfg_scale` |  | number | no | `7` | 1 – 20 | Postavka usmjeravanja audija: povećajte je za veću dosljednost i fokus generiranog sadržaja. Koristi usmjeravanje bez klasifikatora (CFG). |
| `audio_stg_scale` |  | number | no | `0` | 0 – 20 | Upravljanje dosljednošću i fokusom audija putem skale prostorno-vremenskog usmjeravanja (STG); povećajte postavku za jačanje obiju značajki. |
| `audio_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Prilagodba ponovnog skaliranja audija za uravnoteživanje usmjeravanja bez klasifikatora i prostorno-vremenskog usmjeravanja kao omjera. |
| `audio_modality_scale` |  | number | no | `3` | 0 – 10 | Prilagodba modaliteta audija za uravnoteživanje doprinosa videa i audija kao omjera. |
| `gradient_estimation_gamma` |  | number | no | `2` | 0 – 10 | Postavka procjene gradijenta uklanjanja šuma: 0 isključuje procjenu; inače vrijednost određuje gamu. |
| `use_restart_sampling` |  | boolean | no | `false` |  | Prekidač ponovnog uzorkovanja radi moguće bolje kvalitete videa: uključivanje dodaje malo šuma pri svakom koraku uklanjanja šuma. |
| `scheduler` |  | enum (string) | no | `ltx2` | `ltx2`, `linear_quadratic`, `beta` | Odabir planera. |
| `acceleration` |  | enum (string) | no | `regular` | `none`, `regular`, `high`, `full` | Razina ubrzanja primijenjena na obradu. |
| `camera_lora` |  | enum (string) | no | `none` | `dolly_in`, `dolly_out`, `dolly_left`, `dolly_right`, `jib_up`, `jib_down`, `static`, `none` | Odabir Camera LoRA-e za preciznije upravljanje kretanjem u generiranom videu nego samo promptima pokreta kamere. |
| `camera_lora_scale` |  | number | no | `1` | 0 – 1 | Jačina Camera LoRA-e za preciznije upravljanje kretanjem u generiranom videu nego samo promptima pokreta kamere. |
| `negative_prompt` |  | string | no | `news broadcast, 3d animation, computer graphics, pc game, console game, video game, cartoon, childish, watermark, logo, text, on screen text, subtitles, titles, signature, slowmo, static` |  | Negativni prompt koji se koristi tijekom generiranja videa. |
| `seed` |  | integer \| null | no |  |  | Vrijednost sjemena koja pokreće generiranje slučajnih brojeva. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Određuje je li proširivanje prompta omogućeno. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Kontrolira je li provjera sigurnosti omogućena. |
| `video_output_type` |  | enum (string) | no | `X264 (.mp4)` | `X264 (.mp4)`, `VP9 (.webm)`, `PRORES4444 (.mov)`, `GIF (.gif)` | Vrsta izlaza rezultirajućeg videozapisa. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Razina kvalitete rezultirajućeg videozapisa. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Način zapisivanja rezultirajućeg videozapisa. |
| `distill_lora_first_pass_scale` |  | number | no | `0.2` | 0 – 1 | Upravlja skaliranjem distill LoRA-e u prvom prolazu; 0 je isključuje. |
| `distill_lora_second_pass_scale` |  | number | no | `0.5` | 0 – 1 | Upravlja skaliranjem distill LoRA-e u svakom prolazu nakon prvog. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Strana videa koju treba produljiti: odaberite 'backward' za dodavanje sadržaja prije početka ili 'forward' za dodavanje sadržaja nakon završetka. |
| `num_context_frames` |  | integer | no | `25` | 0 – 121 | Broj sličica koji se koristi za kontekst pri produljenju videa. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Sloboda izmjene sadržaja videa određena je ovom jačinom kondicioniranja: manje vrijednosti modelu daju veću slobodu. |
| `audio_strength` |  | number | no | `1` | 0 – 1 | Sloboda izmjene sadržaja audija određena je ovom jačinom kondicioniranja: manje vrijednosti modelu daju veću slobodu. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Upravlja utjecajem završne slike na generirani video. |

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-2.3-22b/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-2.3-22b/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-2.3-22b/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-2.3-22b/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-2.3-22b/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": 180,
    "usd": "0.18",
    "charged": 180,
    "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,
      "width": 1024,
      "height": 768,
      "fps": 1.0,
      "duration": 5,
      "num_frames": 1
    },
    "seed": 42,
    "prompt": "A woman stands still amid a busy neon-lit street at night. The camera slowly dollies in toward her face as people blur past, their motion emphasizing her calm presence. City lights flicker and reflections shift across her denim jacket."
  },
  "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, width, height, fps, duration, num_frames} | Videozapis koji je izradio model. |
| `seed` | integer | Vrijednost sjemena za inicijalizaciju generiranja slučajnih brojeva. |
| `prompt` | string | Prompt koji usmjerava generiranje. |

## Related models

- [LTX-2.3 22B · Text to Video](https://doitong.com/developers/models/ltx-2.3-22b/text-to-video.md) (`ltx-2.3-22b/text-to-video`): $0.00161 / megapixel of output video
- [LTX-2.3 22B · Text to Video · LoRA](https://doitong.com/developers/models/ltx-2.3-22b/text-to-video/lora.md) (`ltx-2.3-22b/text-to-video/lora`): $0.00181 / megapixel of output video
- [LTX-2.3 22B · Image to Video](https://doitong.com/developers/models/ltx-2.3-22b/image-to-video.md) (`ltx-2.3-22b/image-to-video`): $0.00161 / megapixel of output video
- [LTX-2.3 22B · Image to Video · LoRA](https://doitong.com/developers/models/ltx-2.3-22b/image-to-video/lora.md) (`ltx-2.3-22b/image-to-video/lora`): $0.00181 / megapixel of output video
- [LTX 2.3 22B](https://doitong.com/developers/models/ltx-2.3-22b/reference-video-to-video/lora.md) (`ltx-2.3-22b/reference-video-to-video/lora`): $0.00181 / megapixel of output video
- [LTX-2.3 22B · Extend Video · LoRA](https://doitong.com/developers/models/ltx-2.3-22b/extend-video/lora.md) (`ltx-2.3-22b/extend-video/lora`): $0.00181 / megapixel of output video
- [LTX-2.3 22B · Reference Video to Video](https://doitong.com/developers/models/ltx-2.3-22b/reference-video-to-video.md) (`ltx-2.3-22b/reference-video-to-video`): $0.00161 / megapixel of output video
- [LTX-2.3 22B · Video to Video](https://doitong.com/developers/models/ltx-2.3-22b/video-to-video.md) (`ltx-2.3-22b/video-to-video`): $0.00161 / megapixel of output video

## Links

- HTML page: https://doitong.com/developers/models/ltx-2.3-22b/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-2.3-22b/extend-video
- Errors: https://doitong.com/developers/docs/errors
- Model details as JSON: https://api.doitong.com/v1/models/ltx-2.3-22b/extend-video