# LTX-2.3 22B · Extend Video API

> Fortsetter en eksisterende video fra en prompt, med generert lyd og et valgfritt sluttbilde

Tar `video_url` og en `prompt` og genererer en fortsettelse på `num_frames` bilder (9 til 481). En valgfri `end_image_url` angir hvor utvidelsen avsluttes. `match_input_fps` beholder kildens bildefrekvens, `generate_audio` legger til lyd, og `video_size` har standardverdien auto. Utdata kan være mp4, webm, mov eller 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/no/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 brukt som grunnlag for videogenerering. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL som peker til videoen som skal forlenges. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Oppgi et sluttbilde via URL for å definere hvordan den forlengede videoen avsluttes. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Antall bilder i de genererte utdataene. |
| `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` | Dimensjonene til den genererte videoen. |
| `generate_audio` |  | boolean | no | `true` |  | Styrer om videoen inkluderer generert lyd. |
| `use_multiscale` |  | boolean | no | `true` |  | Bryter for generering i flere skalaer for bedre sammenheng og detalj. Med True lager en foreløpig mindre video som veiledning for en ny generering med størrelse som oppfyller eller overstiger de forespurte dimensjonene. |
| `match_input_fps` |  | boolean | no | `true` |  | Overstyring av utdataens bildefrekvens som erstatter standard målfrekvens med kildevideoens FPS når den er aktivert. |
| `fps` |  | number | no | `24` | 1 – 60 | Bildehastighet for utdata-videoen, målt i bilder per sekund. |
| `num_inference_steps` |  | integer | no | `40` | 8 – 50 | Antall utførte inferenssteg. |
| `video_cfg_scale` |  | number | no | `3` | 1 – 20 | Veiledningsinnstilling for video: øk den for større konsistens og fokus i det genererte innholdet. Bruker classifier-free guidance (CFG). |
| `video_stg_scale` |  | number | no | `0` | 0 – 20 | Styrer videoens konsistens og fokus gjennom skalaen for Spatiotemporal Guidance (STG); øk innstillingen for å styrke begge egenskapene. |
| `video_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Justering av videoskalering for å balansere classifier-free guidance mot spatiotemporal guidance som et forhold. |
| `video_modality_scale` |  | number | no | `3` | 0 – 10 | Justering av videomodusen for å balansere bidragene fra video og lyd som et forhold. |
| `audio_cfg_scale` |  | number | no | `7` | 1 – 20 | Veiledningsinnstilling for lyd: øk den for større konsistens og fokus i det genererte innholdet. Bruker classifier-free guidance (CFG). |
| `audio_stg_scale` |  | number | no | `0` | 0 – 20 | Styrer lydens konsistens og fokus gjennom skalaen for Spatiotemporal Guidance (STG); øk innstillingen for å styrke begge egenskapene. |
| `audio_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Justering av lydskalering for å balansere classifier-free guidance mot spatiotemporal guidance som et forhold. |
| `audio_modality_scale` |  | number | no | `3` | 0 – 10 | Justering av lydmodusen for å balansere bidragene fra video og lyd som et forhold. |
| `gradient_estimation_gamma` |  | number | no | `2` | 0 – 10 | Innstilling for estimering av gradient ved støyreduksjon: 0 deaktiverer estimering; ellers angir verdien gamma. |
| `use_restart_sampling` |  | boolean | no | `false` |  | Bryter for omstart av sampling for mulig bedre videokvalitet: aktivering tilfører litt støy ved hvert trinn i støyreduksjonen. |
| `scheduler` |  | enum (string) | no | `ltx2` | `ltx2`, `linear_quadratic`, `beta` | Valg av planlegger. |
| `acceleration` |  | enum (string) | no | `regular` | `none`, `regular`, `high`, `full` | Akselerasjonsnivå brukt på behandlingen. |
| `camera_lora` |  | enum (string) | no | `none` | `dolly_in`, `dolly_out`, `dolly_left`, `dolly_right`, `jib_up`, `jib_down`, `static`, `none` | Valg av kamera-LoRA for mer presis styring av bevegelse i den genererte videoen enn med bare kamerabevegelsesprompter. |
| `camera_lora_scale` |  | number | no | `1` | 0 – 1 | Styrke for kamera-LoRA for mer presis styring av bevegelse i den genererte videoen enn med bare kamerabevegelsesprompter. |
| `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` |  | Negativ prompt som brukes under videogenerering. |
| `seed` |  | integer \| null | no |  |  | Seed-verdi som initialiserer generering av tilfeldige tall. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Styrer om promptutvidelse er aktivert. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Styrer om sikkerhetskontroll er aktivert. |
| `video_output_type` |  | enum (string) | no | `X264 (.mp4)` | `X264 (.mp4)`, `VP9 (.webm)`, `PRORES4444 (.mov)`, `GIF (.gif)` | Utdata type for videoen som resultat. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Kvalitetsnivå for videoen som resultat. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Skrivemodus for videoen som resultat. |
| `distill_lora_first_pass_scale` |  | number | no | `0.2` | 0 – 1 | Styrer skaleringen av distill-LoRA i første pass; bruk 0 for å deaktivere den. |
| `distill_lora_second_pass_scale` |  | number | no | `0.5` | 0 – 1 | Styrer skaleringen av distill-LoRA for hvert pass etter det første. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Siden av videoen som skal forlenges: velg 'backward' for å legge til innhold før begynnelsen eller 'forward' for å legge til innhold etter slutten. |
| `num_context_frames` |  | integer | no | `25` | 0 – 121 | Antall bilder som brukes til å gi kontekst ved forlengelse av videoen. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Friheten til å endre videoinnhold styres av denne betingelsesstyrken: lavere innstillinger gir modellen større spillerom. |
| `audio_strength` |  | number | no | `1` | 0 – 1 | Friheten til å endre lydinnhold styres av denne betingelsesstyrken: lavere innstillinger gir modellen større spillerom. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Styrer hvor mye sluttbildet påvirker den genererte videoen. |

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} | Video produsert av modellen. |
| `seed` | integer | Startverdi som brukes til å initialisere generering av tilfeldige tall. |
| `prompt` | string | Prompt som brukes til å styre genereringen. |

## 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