# Ltx 2.3 Quality · Extend Video API

> ᠵᡠᠶᡝᠨ ᠪᡝ ᠵᡠᠯᡤᡝᠨ ᡳᠯᡤᠠᠨ ᠠᡳᠯᡳ ᠵᡠᠯᡤᡝᠨ ᡩᡝᠵᡳ ᠵᠠᠯᡠᠮᡝ, ᠵᡠᠯᡤᡝᠨ ᡩᡝᠵᡳ ᡴᡝᠰᡳᠨ ᠵᡠᠶᡝᠨ ᡳ ᠵᡠᠯᡤᡝᠨ ᠪᡳᠮᡝ

ᠠᠮᠪᠠ ᠵᡠᠶᡝᠨ ᡩᡝ `prompt` ᠵᡝᠨᡝᠮᡝ ᠵᡠᠯᡤᡝᠨ ᠠᠴᠠᠮᡝ. `extend_direction` ᠪᡝ `forward` ᠵᡝᠨᡝᠮᡝ ᡴᡝᠰᡳᠨ ᠴᡳ ᠵᠠᠯᡠᠮᡝ, ᠠᡳᠯᡳ `backward` ᡳ ᠵᡝᠨᡝᠮᡝ ᠵᡝᠪᡝᠨ ᠪᡝ ᠪᠠᠶᠠᠨᡩᠠᠮᡝ. `num_context_frames` (9 ᠴᡳ 121) ᠪᡝ ᠵᡠᠯᡤᡝᠨ ᠠᠯᡳᠨ ᠵᠠᠯᡠ ᠪᡝ ᠵᠠᠯᡠᠮᡝ, `num_frames` (9 ᠴᡳ 481) ᠪᡝ ᠵᡠᡶᠠᠨ ᠳᡠᠯᡥᡝᠨ ᠪᡝ ᠵᠠᠯᡠᠮᡝ. ᠰᠣᠨᠵᠣᠮᡝ `end_image_url` ᡳ ᡴᡝᠰᡳᠨ ᠵᡠᠶᡝᠨ ᠪᡝ ᠵᡝᠨᡝᠮᡝ, `match_input_fps` ᠵᡝᡵᡤᡳ ᡳ ᠵᠠᠯᡠ ᠪᡝ ᠵᠠᠯᡠᠮᡝ.

- 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/mnc/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 |  |  | ᠰᡠᠨᡤᠠᡳ ᡝᠮᡤᡳᠯᡝᠮᡝ ᠵᡠᠯᡤᡳ ᠠᡵᠠᡥᠠ ᡥᡡᠯᠠᠨ. |
| `video_url` | `video` | string (video URL) | yes |  |  | ᡝᠮᡤᡳᠯᡝᠮᡝ ᠵᡠᠯᡤᡳ ᠰᡠᠨᡤᠠᡳ URL. |
| `extend_direction` |  | enum (string) | no | `forward` | `forward`, `backward` | ᠰᡠᠨᡤᠠ ᡝᠮᡤᡳᠯᡝᠮᡝ ᠠᡵᠠᡥᠠ: 'backward' ᠪᡝ ᠵᡠᠯᡤᡳ ᠰᡠᠨᡤᠠ ᠪᡝ ᠪᡠᠶᡝᠮᡝ, 'forward' ᠪᡝ ᡩᠠᠯᡵᡳ ᠰᡠᠨᡤᠠ ᠪᡝ ᠵᠠᠯᠠᠮᡳ. |
| `num_frames` |  | integer | no | `121` | 9 – 481 | ᡝᠮᡤᡳᠯᡝᠮᡝ ᡶᡳᠯᡝᠮᡝᠨ, ᠵᠠᠯᠠᠨ ᠪᠠᡳ ᡶᡳᠶᠠᠨ ᠪᡝ ᠠᠪᠠᠮᡳ: 24 fps ᠵᡝᠴᡝᠨ 480p 20 ᠰᡝᡴᡠᠨᡩ, 720p 11 ᠰᡝᡴᡠᠨᡩ, 1080p 5 ᠰᡝᡴᡠᠨᡩ. 422 ᡩᠠᠯᡳᠯᠠᡥᠠᠴᡳ `num_frames` ᠪᡝ ᡝᠮᡤᡳᠯᡝᠮᡝ ᠵᠠᠯᠠᠨ ᠪᡝ ᠰᡣᠣᠯᠣᠮᡳ. ᠵᠠᠯᠠᠨᡳ ᡶᡳᠯᡝᠮᡝᠨ ᠪᡝ ᡳᠯᡳᠪᡠᠮᡳ; ᠵᡠᠯᡤᡳ ᠵᡠᡵᡤᠠᠨ = (`num_frames` - `num_context_frames`) / `frames_per_second` ᠰᡝᡴᡠᠨᡩ. |
| `num_context_frames` |  | integer | no | `25` | 9 – 121 | ᡝᠮᡤᡳᠯᡝᠮᡝ ᠠᠪᠠᡥᠠ ᠵᡠᠯᡤᡳ ᡶᡳᠯᡝᠮᡝᠨ ᡳ ᠶᠠᠯᠠᠨ; LTX ᡳ 8k+1 ᡤᡳᠶᠠᠨ ᠪᡝ ᠵᠠᠯᠠᠮᡝ ᠵᠠᡳᠯᠠᠮᡳ. |
| `end_image_url` | `end_image` | string (image URL) \| null | no |  |  | ᠵᡠᠯᡤᡳ ᠵᠠᠯᠠᠨ ᡳ ᡩᠠᠯᡵᡳ ᠵᡠᠯᡤᡳ ᠶᠠᠯᡤᠠᠨᠠᡳ ᡤᠠᠳᠠᠨ. |
| `end_image_strength` |  | number | no | `1` | 0 – 1 | ᡶᡠᠯᡤᠠᠨ ᠶᠠᠯᡤᠠᠨᠠᡳ ᡤᠠᠯᡠᠨ: ᡝᠮᡤᡳᠯᡝᠮᡝ ᠮᠣᡩᡝᠯᡳ ᡠᠯᡥᡳ ᡶᠠᠯᡤᠠᠨ ᠪᡝ ᠪᡠᠮᡳ; 1.0 ᡝᠵᡝᠨ ᠵᠠᠪᡠᠮᡳ. |
| `resolution` |  | object {width, height} \| enum (string) | no | `auto` | `auto`, `square_hd`, `square`, `portrait_4_3`, `portrait_16_9`, `landscape_4_3`, `landscape_16_9` | ᠪᡠᠶᡝᠮᡝᠨᡳ ᠵᠠᠯᠠᠨ, 32px ᡩᡠᠯᡝᡵᡝ ᠵᠠᠯᠠᠨ; 1920x1080 ᡝᠮᡠ 1888x1056 ᠪᡠᠮᡳ. 'auto' ᠪᡝ LTX ᡳ ᠵᠠᠯᠠᠨ ᠪᠠᡳ ᠵᠠᠯᠠᠨ ᡳ ᠵᠠᠩᡤᡳ ᠪᡝ ᠠᠪᠠᠮᡳ. |
| `match_input_fps` |  | boolean | no | `true` |  | ᠪᡠᠶᡝᠮᡝᠨᡳ FPS ᡩᡠᡵᠠᠨ ᠪᡝ ᡠᠯᡥᡳᠯᡝᠮᡝ; `frames_per_second` ᠪᡝ ᡝᠮᡤᡳᠯᡝᠮᠪᡳ. ᠵᠠᠯᠠᠨ ᠪᡝ ᠨᠠᡩᠠᠨ ᠪᡝ ᠰᡣᠣᠯᡣᠣᠮᡳ. |
| `frames_per_second` |  | number | no | `24` | 1 – 60 | ᠪᡠᠶᡝᠮᡝᠨᡳ ᡶᡳᠯᡝᠮᡝᠮᡝ ᠵᠠᠯᠠᠨ, ᡶᡳᠯᡝᠮᡝᠨ ᡳ ᠨᠠᡩᠠᠨ ᠰᡝᡴᡠᠨᡩ. |
| `video_strength` |  | number | no | `1` | 0 – 1 | ᠵᡠᠯᡤᡳ ᠪᡝ ᡶᠠᠯᡤᠠᠯᠠᡵᠠ ᠮᠣᡩᡝᠯᡳ ᡠᠯᡥᡳ ᡶᠠᠯᡤᠠᠨ ᠪᡝ ᠪᡠᠮᡳ; 1.0 ᡳ ᡝᠮᡤᡳᠯᡝᠮᡝ ᡶᡳᠯᡝᠮᡝᠨ ᡳ ᡝᠮᡠ ᠪᡝ ᠵᠠᠪᡠᠮᡳ. |
| `num_inference_steps` |  | integer | no | `15` | 8 – 30 | ᡳᠨᡶᡝᡵᡝᠨᠰᡳ ᠠᡵᠠᡥᠠᡳ ᠵᠠᡵᡤᠠᠨ ᠪᡝ 30 ᠵᡝᠴᡝᠨ ᠪᠠᡩᠠ ᠪᡠᠶᡝᠮᡝ; ᠵᡠᠯᡝ 15. |
| `guidance_scale` |  | number | no | `1` | 1 – 20 | ᠮᡝᠯᡥᡝᠨᡳ ᡩᠠᠯᡤᠠᠨ ᠪᡝ ᡝᠨᡩᡠᡵᡳᠯᡝᠮᡝ ᠵᠠᠯᠠᠨ ᠪᡝ ᠠᠪᠠᠮᡳ; ᠵᡠᠯᡝ ᠵᠠᠯᠠᠨ ᠵᠠᡵᡤᠠᠨ ᠪᡠᠶᡝᠮᡝᠨ ᠪᡝ ᡶᠠᠰᡥᠠ ᠠᡵᠠᠯᠠᠮᠪᡳ. |
| `generate_audio` |  | boolean | no | `true` |  | ᡝᠮᡤᡳᠯᡝᠮᡝ ᡤᡳᠰᡠᠨᡳ ᠠᡵᠠᡥᠠ: ᠠᠮᠪᠠᠯᠠᡵᠠ ᠵᡠᠯᡤᡳ ᠠᡵᠠᡥᠠ ᠪᡝ ᠠᠮᡵᠠᠰᡳ ᡩᠠᠮᡠ ᠪᡠᠮᡳ; ᠠᠮᠪᠠᠯᠠᡴᡳ ᡝᠮᡤᡳᠯᡝᠮᡝ ᡤᡳᠰᡠᠨ ᠪᡝ ᠪᡠᠶᡝᠮᡝ ᠪᠠᡳ ᠵᡠᠯᡤᡳ ᡤᡳᠰᡠᠨ ᠪᡝ ᡴᡠᠰᡠᠯᠠᠮᠪᡳ. |
| `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` |  | ᠪᡠᠶᡝᠮᡝᠨ ᡩᡠᠯᡝᠮᡝ ᡠᠯᡥᡳᠯᡝᠮᡝ ᠠᠪᠠᡥᠠ ᠠᠰᡥᠠᠨ ᡥᡡᠯᠠᠨ. |
| `seed` |  | integer \| null | no |  |  | ᠪᡠᠶᡝᠮᡝ ᡩᡝ ᠰᠠᡳᠨ ᠪᡳᠰᡳᠮᡝ ᠪᠠᠨᠵᡳᠨᠠᠮᡝ᠉ None ᡩᡝ ᠪᡳᠮᡝ ᠪᠠᠨᠵᡳᠨ ᡤᠣᠯᠣᠮᡝ᠉ |
| `enable_prompt_expansion` |  | boolean | no | `true` |  | ᡥᡡᠯᠠᠨ ᠪᡝ ᡩᡝᠯᡝᠪᡠᡵᡝ ᠪᡝ ᡝᠪᡠᡵᡝ ᡝᠪᡠᡵᠠᡴᡡ ᠪᡝ ᡠᠵᡳᠮᠪᡳ. |
| `enable_safety_checker` |  | boolean | no | `true` |  | ᠠᠮᠠᠯᠠᠮᡝ ᠰᠠᠬᡳᠶᠠᠨ ᡳ ᠵᠠᠯᡳᠨ ᠪᡳᠰᡳᡵᡝ ᠵᠠᡴᡠᠨᠠᠮᡝ᠉ |
| `video_quality` |  | enum (string) | no | `high` | `low`, `medium`, `high`, `maximum` | ᠪᡠᠶᡝᠮᡝᠨᡳ ᠰᡠᠨᡤᠠᡳ ᠵᠠᠯᠠᠨ ᡳ ᠴᡳᠨᠠᡵᡤᡳ ᠵᠠᠯᠠᠨ. |
| `video_write_mode` |  | enum (string) | no | `balanced` | `fast`, `balanced`, `small` | ᠪᡠᠶᡝᠮᡝᠨᡳ ᠰᡠᠨᡤᠠᡳ ᠪᡠᠶᡝᠨ ᡩᡠᠯᡝᠮᡝ. |

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} | ᠮᠣᠳᡝᠯ ᠪᡠᠶᡝᡥᠠᠨ ᠰᡠᠨᡤᠠ. |
| `seed` | integer | ᠪᡠᠶᡝᠮᡝᠨ ᡳ ᡥᡡᠯᠠᠨ ᡶᡝᡵᡤᡝᠨ. |
| `prompt` | string | ᠪᡠᠶᡝᠮᡝᠨᡳ ᡥᡡᠯᠠᠨ, ᠪᡠᠶᡝᠮᡝᠨ ᡩᡠᠯᡝᠮᡝ ᡝᠮᡤᡳᠯᡝᠮᡝ ᠠᠪᠠᡥᠠ ᠪᡝ ᡴᡳᠶᠠᠯᠠᡵᠠ. |

## Related models

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## 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