# LTX-2.3 22B · Extend Video API

> Zet een bestaande video voort vanaf een prompt, met gegenereerde audio en een optionele eindafbeelding

Neemt `video_url` en een `prompt` en genereert een voortzetting van `num_frames` frames (9 tot 481). Een optionele `end_image_url` bepaalt waar de uitbreiding eindigt. `match_input_fps` behoudt de framesnelheid van de bron, `generate_audio` voegt geluid toe en `video_size` staat standaard op auto. De uitvoer kan mp4, webm, mov of GIF zijn.

- 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/nl/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 die als basis voor videogeneratie wordt gebruikt. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL die verwijst naar de video die wordt verlengd. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Lever via URL een eindframeafbeelding aan om te bepalen hoe de verlengde video eindigt. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Aantal frames voor de gegenereerde uitvoer. |
| `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` | Afmetingen van de gegenereerde video. |
| `generate_audio` |  | boolean | no | `true` |  | Bepaalt of de video gegenereerde audio bevat. |
| `use_multiscale` |  | boolean | no | `true` |  | Schakelaar voor generatie op meerdere schalen voor betere samenhang en details. Met True stuurt een voorlopige kleinere video een tweede generatie aan waarvan de grootte minstens de gevraagde afmetingen heeft. |
| `match_input_fps` |  | boolean | no | `true` |  | Overschrijving van de uitvoerframesnelheid die, wanneer ingeschakeld, de standaard-FPS vervangt door de FPS van de bronvideo. |
| `fps` |  | number | no | `24` | 1 – 60 | Framesnelheid van de uitvoervideo, gemeten in frames per seconde. |
| `num_inference_steps` |  | integer | no | `40` | 8 – 50 | Aantal uitgevoerde inferentiestappen. |
| `video_cfg_scale` |  | number | no | `3` | 1 – 20 | Instelling voor videoguidance: verhoog deze voor meer consistentie en focus in de gegenereerde content. Gebruikt classifier-free guidance (CFG). |
| `video_stg_scale` |  | number | no | `0` | 0 – 20 | Regelt vide consistentie en focus via de schaal van Spatiotemporal Guidance (STG); verhoog de instelling om beide eigenschappen te versterken. |
| `video_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Aanpassing voor videoschaling om classifier-free guidance en spatiotemporal guidance als verhouding in balans te brengen. |
| `video_modality_scale` |  | number | no | `3` | 0 – 10 | Aanpassing van de videomodaliteit om de bijdragen van video en audio als verhouding in balans te brengen. |
| `audio_cfg_scale` |  | number | no | `7` | 1 – 20 | Instelling voor audioguidance: verhoog deze voor meer consistentie en focus in de gegenereerde content. Gebruikt classifier-free guidance (CFG). |
| `audio_stg_scale` |  | number | no | `0` | 0 – 20 | Regelt audioconsistentie en -focus via de schaal van Spatiotemporal Guidance (STG); verhoog de instelling om beide eigenschappen te versterken. |
| `audio_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Aanpassing voor audioschaling om classifier-free guidance en spatiotemporal guidance als verhouding in balans te brengen. |
| `audio_modality_scale` |  | number | no | `3` | 0 – 10 | Aanpassing van de audiomodaliteit om de bijdragen van video en audio als verhouding in balans te brengen. |
| `gradient_estimation_gamma` |  | number | no | `2` | 0 – 10 | Instelling voor schatting van de denoising-gradiënt: 0 schakelt de schatting uit; anders geeft de waarde gamma aan. |
| `use_restart_sampling` |  | boolean | no | `false` |  | Schakelaar voor opnieuw samplen voor mogelijk betere videokwaliteit: inschakelen voegt bij elke denoisingstap een beetje ruis toe. |
| `scheduler` |  | enum (string) | no | `ltx2` | `ltx2`, `linear_quadratic`, `beta` | Selectie van de scheduler. |
| `acceleration` |  | enum (string) | no | `regular` | `none`, `regular`, `high`, `full` | Versnellingsniveau dat op de verwerking wordt toegepast. |
| `camera_lora` |  | enum (string) | no | `none` | `dolly_in`, `dolly_out`, `dolly_left`, `dolly_right`, `jib_up`, `jib_down`, `static`, `none` | Selectie van de camera-LoRA voor nauwkeurigere bewegingsregeling in de gegenereerde video dan met alleen camerabewegingsprompts. |
| `camera_lora_scale` |  | number | no | `1` | 0 – 1 | Sterkte van de camera-LoRA voor nauwkeurigere bewegingsregeling in de gegenereerde video dan met alleen camerabewegingsprompts. |
| `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` |  | Negatieve prompt die tijdens de videogeneratie wordt gebruikt. |
| `seed` |  | integer \| null | no |  |  | Seedwaarde die de generatie van willekeurige getallen initialiseert. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Bepaalt of promptuitbreiding is ingeschakeld. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Bepaalt of veiligheidscontrole is ingeschakeld. |
| `video_output_type` |  | enum (string) | no | `X264 (.mp4)` | `X264 (.mp4)`, `VP9 (.webm)`, `PRORES4444 (.mov)`, `GIF (.gif)` | Uitvoertype van de resulterende video. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Kwaliteitsniveau van de resulterende video. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Schrijfmodus van de resulterende video. |
| `distill_lora_first_pass_scale` |  | number | no | `0.2` | 0 – 1 | Regel de schaal van de distill-LoRA voor de eerste pass; gebruik 0 om deze uit te schakelen. |
| `distill_lora_second_pass_scale` |  | number | no | `0.5` | 0 – 1 | Regel de schaal van de distill-LoRA voor elke pass na de eerste. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Kant van de video die moet worden verlengd: kies 'backward' om content vóór het begin toe te voegen of 'forward' om content na het einde toe te voegen. |
| `num_context_frames` |  | integer | no | `25` | 0 – 121 | Frameaantal dat wordt gebruikt om context te leveren bij het verlengen van de video. |
| `video_strength` |  | number | no | `1` | 0 – 1 | De vrijheid om videocontent te wijzigen wordt door deze conditioneringssterkte geregeld: lagere instellingen geven het model meer speelruimte. |
| `audio_strength` |  | number | no | `1` | 0 – 1 | De vrijheid om audiocontent te wijzigen wordt door deze conditioneringssterkte geregeld: lagere instellingen geven het model meer speelruimte. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Regel hoeveel invloed de eindafbeelding op de gegenereerde video heeft. |

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 die door het model is geproduceerd. |
| `seed` | integer | Seedwaarde voor het initialiseren van het genereren van willekeurige getallen. |
| `prompt` | string | Prompt die de generatie stuurt. |

## 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