# Ltx 2.3 Quality · Extend Video API

> Ka haere tonu i tētahi ataata whakamua, whakamuri rānei, me tētahi whakaahua tāpare matua whakamutunga kōwhiringa

Ka whakaroa i tētahi topenga mā te whakaputa ataata hou ka aratakina e tētahi `prompt` e hiahiatia ana. Ko `extend_direction` he `forward` hei haere tonu mai i te mutunga, he `backward` rānei hei waihanga tīmatanga hou. Mā `num_context_frames` (9 ki te 121) e tautuhi te nui o te īnaki ki te pūtake, ā, mā `num_frames` (9 ki te 481) e tautuhi te roa o te wāhanga. Ka whakaū tētahi `end_image_url` kōwhiringa i te anga matua whakamutunga, ā, mā `match_input_fps` e pupuri te auau anga o te pūtake.

- 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/mi/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 |  |  | Tohutohu e tohu ana i te haere tonutanga e hiahiatia ana o te ataata. |
| `video_url` | `video` | string (video URL) | yes |  |  | URL e tohu ana ki te ataata ka whakawhānuitia. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | Aratau whakawhānui ataata: mā 'backward' ka hangaia he tīmatanga hou, ā, mā 'forward' ka haere tonu te ataata i tua atu i tōna mutunga. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | Tatau anga whakawhānui, kei raro i te pūtea whakaputanga pūmau mō te taumira whakareatia ki ngā anga: i te 24 fps, tata ki te 20 hēkona mō te akomanga 480p, 11 hēkona mō te akomanga 720p, 5 hēkona mō te akomanga 1080p. Mā ngā tono ka hipa i te pūtea ka whakahoki 422; whakaitia `num_frames`, kōwhiria rānei he taumira iti ake. Kei roto i te tatau ngā `num_context_frames` e inaki ana ki te pūtake, nō reira ko te roanga tāpiri he āhua (`num_frames` - `num_context_frames`) / `frames_per_second` hēkona. |
| `num_context_frames` |  | integer | no | `25` | 9 – 121 | Tatau anga pūtake e tonoa ana mō te horopaki/inaki whakawhānui, he mea here ki te maha o ngā anga kei te pūtake. Ka whakahekehia te tatau kia uru ki te mātiti LTX o 8k+1. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | Atahanga keyframe kōwhiringa hei whakatakoto i te anga tuatahi hou o te whakawhānui ina whakawhānui whakamuri, i te anga whakamutunga rānei ina whakawhānui whakamua. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | Te kaha conditioning keyframe-mutunga kōwhiringa: mā te whakaiti ka nui ake te wātea o te tauira, engari mā te 1.0 ka tino ū te ōrite. |
| `resolution` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | Ngā āhuatanga ataata kua whakaputaina, kua whakaritea ki ngā pikinga 32px—hei tauira, ka noho 1888x1056 te 1920x1080—ā, ka whakaritea te pūtake ki ēnei āhuatanga mō te putanga kua tuituia. Ka roa ake ngā whakawhānuitanga pūmau i ngā taumira iti, ka poto ake i ngā taumira tiketike. Mā te kōwhiri 'auto' e pupuri ngā āhuatanga me te ōwehenga āhuatanga o te pūtake ki te whānuitanga e whakaaetia ana e LTX. |
| `match_input_fps` |  | boolean | no | `true` |  | Whakarite tere anga putanga kia ōrite ki te pūtake ina whakakāhia, ka whakakapi i `frames_per_second`. Ka whakaawhiwhia te FPS pūtake ki te tauoti, ā, ka herea ki te awhe e tautokona ana. |
| `frames_per_second` |  | number | no | `24` | 1 – 60 | Tere anga ataata putanga, ka inehia ki ngā anga ia hēkona. |
| `video_strength` |  | number | no | `1` | 0 – 1 | Te kaha conditioning horopaki pūtake: mā te whakaiti ka nui ake te wātea o te tauira. I te 1.0, ka mau ngā anga inaki ki te pūtake, kia ngātahi ai te whakawhitinga. |
| `num_inference_steps` |  | integer | no | `15` | 8 – 30 | Tautuhia te maha o ngā hīkoi inference hei whakahaere, tae atu ki te 30; ki te waiho kia kore e whakarerekēhia, ka whakamahia te 15. |
| `guidance_scale` |  | number | no | `1` | 1 – 20 | Whakaritea te ārahi classifier-free mā tēnei tauine; ko te whakatikatika taunoa e whāia ana ko te kounga tiketike me te whakaputanga tere. |
| `generate_audio` |  | boolean | no | `true` |  | Whakakā ororongo whakawhānui: ina whakawetohia ka noho wahangu te wāhanga tāpiri, engari ka pupuri i te riu ororongo o te ataata pūtake. Ina whakakāhia, ka whakaputaina he ororongo mō te whakawhānui, ka crossfade ki te pūtake i te hononga. |
| `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` |  | Tohutohu tōraro e tohu ana i ngā mea me karo i te whakaputanga. |
| `seed` |  | integer \| null | no |  |  | Te kākano e taea ai te tārua o te whakaputanga. Mā te tautuhi ki None e kōwhiri matapōkeretia ai he kākano. |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | Ka whakahaere mēnā kua whakahohea te whakawhānui tohutohu. |
| `enable_safety_checker` |  | boolean | no | `true` |  | Ka whakahaere mēnā kua whakakāhia te tirotiro haumaru. |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | Tatūkē kounga ka whakamahia ki te ataata putanga. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | Aratau tuhi mō te ataata ka puta. |

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} | Ataata i whakaputaina e te tauira. |
| `seed` | integer | Seed tūturu ka whakamahia i te whakaputanga. |
| `prompt` | string | Tohutohu whakaputanga, tae atu ki ngā whakawhānuitanga i whakamahia i mua i te whakamahinga. |

## 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