# LTX-2.3 22B · Extend Video API

> Heldur áfram fyrirliggjandi myndskeiði út frá boði, með mynduðu hljóði og valfrjálsri lokamynd

Tekur `video_url` og `prompt` og býr til framhald með `num_frames` römmum (9 til 481). Valfrjálst `end_image_url` setur hvar framlengingunni lýkur. `match_input_fps` heldur rammatíðni upprunans, `generate_audio` bætir við hljóði og `video_size` er sjálfgefið auto. Úttakið getur verið mp4, webm, mov eða 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/is/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 |  |  | Kvaðning sem notuð er sem grunnur að myndbandagerð. |
| `video_url` | `video` | string (video URL) | yes |  |  | Slóð á myndbandið sem verður lengt. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Gefðu upp lokaramma sem mynd með vefslóð til að skilgreina hvernig lengda myndbandinu lýkur. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Fjöldi ramma í myndbandsúttakinu. |
| `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` | Mál myndbandsins sem verður til. |
| `generate_audio` |  | boolean | no | `true` |  | Stjórnar því hvort myndbandið innihaldi myndað hljóð. |
| `use_multiscale` |  | boolean | no | `true` |  | Kveikja fyrir fjölkvarða-efnisgerð til að bæta samræmi og smáatriði. Með True leiðbeinir fyrst minna myndband annarri efnisgerð þar sem stærðin nær umbeðnum málum eða fer yfir þau. |
| `match_input_fps` |  | boolean | no | `true` |  | Yfirskrifun á úttaksrammahraða sem kemur í stað sjálfgefins mark-FPS með FPS upprunamyndbandsins þegar hún er virk. |
| `fps` |  | number | no | `24` | 1 – 60 | Rammatíðni úttaksmyndbands, mæld í römmum á sekúndu. |
| `num_inference_steps` |  | integer | no | `40` | 8 – 50 | Fjöldi framkvæmda ályktunarskrefa. |
| `video_cfg_scale` |  | number | no | `3` | 1 – 20 | Leiðsagnarstilling myndbands: hækkaðu hana fyrir meira samræmi og fókus í mynduðu efni. Notar classifier-free guidance (CFG). |
| `video_stg_scale` |  | number | no | `0` | 0 – 20 | Stýrir samræmi og fókus myndbands með Spatiotemporal Guidance (STG)-kvarðanum; hækkaðu stillinguna til að styrkja hvort tveggja. |
| `video_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Endurskölunarstilling myndbands sem jafnar classifier-free- og tímarúmsleiðsögn sem hlutfall. |
| `video_modality_scale` |  | number | no | `3` | 0 – 10 | Aðlögun myndbandshams sem jafnar framlag myndbands og hljóðs sem hlutfall. |
| `audio_cfg_scale` |  | number | no | `7` | 1 – 20 | Hljóðleiðsagnarstilling: hækkaðu hana fyrir meira samræmi og fókus í mynduðu efni. Notar classifier-free guidance (CFG). |
| `audio_stg_scale` |  | number | no | `0` | 0 – 20 | Stýrir samræmi og fókus hljóðs með Spatiotemporal Guidance (STG)-kvarðanum; hækkaðu stillinguna til að styrkja hvort tveggja. |
| `audio_rescaling_scale` |  | number | no | `0.7` | 0 – 1 | Endurskölunarstilling hljóðs sem jafnar classifier-free- og tímarúmsleiðsögn sem hlutfall. |
| `audio_modality_scale` |  | number | no | `3` | 0 – 10 | Aðlögun hljóðhams sem jafnar framlag myndbands og hljóðs sem hlutfall. |
| `gradient_estimation_gamma` |  | number | no | `2` | 0 – 10 | Stilling fyrir mat á suðunarstigul: 0 slekkur á matinu; annars tilgreinir gildið gamma. |
| `use_restart_sampling` |  | boolean | no | `false` |  | Kveikja fyrir endurræsingu sýnatöku sem getur bætt myndbandsgæði: þegar hún er virk bætist smá suð við hvert suðunarskref. |
| `scheduler` |  | enum (string) | no | `ltx2` | `ltx2`, `linear_quadratic`, `beta` | Val á tímaáætlun. |
| `acceleration` |  | enum (string) | no | `regular` | `none`, `regular`, `high`, `full` | Hröðunarstig sem notað er við úrvinnslu. |
| `camera_lora` |  | enum (string) | no | `none` | `dolly_in`, `dolly_out`, `dolly_left`, `dolly_right`, `jib_up`, `jib_down`, `static`, `none` | Val á myndavélar-LoRA til að stjórna hreyfingu í mynduðu myndbandi nákvæmar en kvaðningar um hreyfingu myndavélar einar og sér. |
| `camera_lora_scale` |  | number | no | `1` | 0 – 1 | Styrkur myndavélar-LoRA til að stjórna hreyfingu í mynduðu myndbandi nákvæmar en kvaðningar um hreyfingu myndavélar einar og sér. |
| `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` |  | Neikvæð kvaðning notuð við efnisgerð myndbands. |
| `seed` |  | integer \| null | no |  |  | Fræ sem frumstillir slembitölugerð. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Stýrir því hvort kvaðning sé útvíkkuð. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Stýrir því hvort öryggisathugun sé virk. |
| `video_output_type` |  | enum (string) | no | `X264 (.mp4)` | `X264 (.mp4)`, `VP9 (.webm)`, `PRORES4444 (.mov)`, `GIF (.gif)` | Úttakstegund myndbandsins sem verður til. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Gæðastig myndbandsins sem verður til. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Skrifhamur myndbandsins sem verður til. |
| `distill_lora_first_pass_scale` |  | number | no | `0.2` | 0 – 1 | Stjórnar skölun distill-LoRA í fyrstu umferð; notaðu 0 til að slökkva á henni. |
| `distill_lora_second_pass_scale` |  | number | no | `0.5` | 0 – 1 | Stjórnar skölun distill-LoRA í öllum umferðum eftir þá fyrstu. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Hlið myndbandsins sem á að lengja: veldu 'backward' til að bæta efni fyrir upphaf þess eða 'forward' til að bæta efni eftir lok þess. |
| `num_context_frames` |  | integer | no | `25` | 0 – 121 | Fjöldi ramma sem notaður er til að veita samhengi við lengingu myndbandsins. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Frelsi til að breyta efni myndbandsins ræðst af þessum skilyrðingarstyrk: lægri gildi gefa líkaninu meira svigrúm. |
| `audio_strength` |  | number | no | `1` | 0 – 1 | Frelsi til að breyta hljóðefni ræðst af þessum skilyrðingarstyrk: lægri gildi gefa líkaninu meira svigrúm. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Stjórnar hversu mikil áhrif lokamyndin hefur á myndaða myndbandið. |

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} | Myndband sem líkanið býr til. |
| `seed` | integer | Fræsgildi notað til að frumstilla myndun slembitalna. |
| `prompt` | string | Kvaðning notuð til að leiðbeina efnisgerð. |

## 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