# Ltx 2.3 Quality · Extend Video API

> Leanaidh e air adhart le bhidio no air ais, le ìomhaigh prìomh-fhrèam dheireannaich roghainneil

Leudaich criomag a th’ ann mar-thà le bhith a’ gineadh fhilmichean ùra fo stiùir `prompt` riatanach. Tha `extend_direction` `forward` gus leantainn bhon deireadh, no `backward` gus toiseach ùr a chruthachadh. Bidh `num_context_frames` (9 gu 121) a’ suidheachadh na tha den tùs a’ dol thairis air, agus bidh `num_frames` (9 gu 481) a’ suidheachadh fad na roinne. Bidh `end_image_url` roghainneil a’ socrachadh na prìomh-fhrèama mu dheireadh, agus bidh `match_input_fps` a’ cumail ìre-fhrèama an tùis.

- 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/gd/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 a shònraicheas an leantainn bhidio a tha thu ag iarraidh. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL a chomharraicheas am bhidio a thèid a leudachadh. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Modh leudachaidh bhidio: cruthaichidh 'backward' toiseach ùr, agus leanaidh 'forward' am bhidio seachad air a chrìoch. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Àireamh frèaman an leudachaidh, fo bhuidseat gineadh seasmhach air dùmhlachd-bhreacaidh air iomadachadh le frèaman: aig 24 fps, mu 20 diog airson clas 480p, 11 diog airson clas 720p, no 5 diog airson clas 1080p. Tillidh iarrtasan a thèid thairis air a’ bhuidseit 422; lughdaich `num_frames` no tagh dùmhlachd-bhreacaidh nas lugha. Tha an àireamh a’ gabhail a-steach `num_context_frames` a tha a’ dol thairis air an tùs, agus mar sin tha an ùine a bharrachd mu (`num_frames` - `num_context_frames`) / `frames_per_second` diogan. |
| `num_context_frames` |  | integer | no | `25` | 9 – 121 | Àireamh frèaman tùsail a chaidh iarraidh airson co-theacsa/overlap leudachaidh, cuibhrichte leis an àireamh de fhrèaman a tha san tùs. Tha an àireamh air a chuairteachadh sìos gus freagairt air griod LTX de 8k+1. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Ìomhaigh keyframe roghainneil a shuidhicheas a’ chiad fhrèam ùr den leudachaidh nuair a thèid leudachadh air ais, no an frèam mu dheireadh nuair a thèid leudachadh air adhart. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Neart conditionachaidh end-keyframe roghainneil: le bhith ga lùghdachadh gheibh am modail barrachd saorsa, agus bidh 1.0 a’ cur an gnìomh maids cheart. |
| `resolution` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Tomhasan a’ bhidio a chaidh a ghineadh, air an co-thaobhadh ri àrdachaidhean 32px—mar eisimpleir, bidh 1920x1080 na 1888x1056—agus an tùs air ath-mheudachadh gu na tomhasan seo airson an às-chuir fuaighte. Faodaidh leudachaidhean seasmhach a bhith nas fhaide aig dùmhlachdan-bhreacaidh nas ìsle agus nas giorra aig feadhainn nas àirde. Le bhith a’ taghadh 'auto' cumaidh sin tomhasan agus co-mheas taobh an tùs cho fad ’s a cheadaicheas crìochan LTX. |
| `match_input_fps` |  | boolean | no | `true` |  | Ma tha e an comas, bidh ìre-frèam an às-chuir a’ maidseadh an tùs, a’ dol thairis air `frames_per_second`. Tha FPS an tùs air a chuairteachadh gu àireamh shlàn agus air a chuingealachadh ris an raon le taic. |
| `frames_per_second` |  | number | no | `24` | 1 – 60 | Ìre-frèam bhidio an às-chuir, air a thomhas ann am frèaman gach diog. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Neart conditionachaidh co-theacsa an tùs: le bhith ga lùghdachadh gheibh am modail barrachd saorsa. Aig 1.0, bidh na frèaman a tha a’ dol thairis air glaiste ris an tùs, a’ dèanamh an eadar-ghluasaid rèidh. |
| `num_inference_steps` |  | integer | no | `15` | 8 – 30 | Suidhich cia mheud ceum inference a ruitheas, suas gu 30; ma thèid seo fhàgail gun atharrachadh, thèid 15 a chleachdadh. |
| `guidance_scale` |  | number | no | `1` | 1 – 20 | Atharraich classifier-free guidance leis an sgèile seo; tha an gleusadh bun-roghainn aige ag amas air càileachd àrd agus gineadh luath. |
| `generate_audio` |  | boolean | no | `true` |  | Toglaich claisneachd an leudachaidh: fàgaidh dheth an earrann a bharrachd sàmhach fhad ’s a chumas e slighe claisneachd a’ bhidio thùsail. Cruthaichidh air claisneachd airson an leudachaidh agus nì e crossfade leis an tùs aig an t-snaim. |
| `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 àicheil a shònraicheas dè bu chòir don ghineadh a sheachnadh. |
| `seed` |  | integer \| null | no |  |  | Sìol a nì gineadh ath-riochdachail. Le bhith ga shuidheachadh gu None, thèid sìol a thaghadh air thuaiream. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Smachd air a bheil leudachadh a’ phrompt air a chomasachadh. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Smachd air co-dhiù a bheil sgrùdadh sàbhailteachd air a chomasachadh. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Ro-shuidheachadh càileachd air a chur an sàs don bhidio às-chuir. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Modh sgrìobhaidh airson a’ bhidio a thig às. |

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} | Bhidio a rinn am modail. |
| `seed` | integer | An seed fhèin a chaidh a chur an sàs rè gineadh. |
| `prompt` | string | Prompt gineadh, a’ gabhail a-steach leudachadh sam bith a chaidh a chur an sàs mus deach a chleachdadh. |

## 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