# Ltx 2.3 Quality > Generate high-quality video with audio from reference video, text and images using LTX-2.3 ## Overview - **Endpoint**: `https://fal.run/fal-ai/ltx-2.3-quality/reference-video-to-video` - **Model ID**: `fal-ai/ltx-2.3-quality/reference-video-to-video` - **Category**: video-to-video - **Kind**: inference ## Pricing Your request will cost $0.0024075 per megapixel of generated video data (width × height × frames), rounded up. For example, if you generate a video that is 121 frames long at 1280 × 720, your total generated video is ≈112 MP, and your request will cost $0.270. For more details, see [fal.ai pricing](https://fal.ai/pricing). ## API Information This model can be used via our HTTP API or more conveniently via our client libraries. See the input and output schema below, as well as the usage examples. ### Input Schema The API accepts the following input parameters: - **`prompt`** (`string`, _required_): The prompt to guide generation. - Examples: "A dancer in a flowing red dress against a black backdrop, studio lighting, cinematic." - **`video_url`** (`string`, _required_): The URL of the reference video that supplies motion/structure. - Examples: "https://v3b.fal.media/files/b/0a8824b1/sdm0KfmenrlywesfzY1Y1_if6euPp1.mp4" - **`image_url`** (`string`, _optional_): Optional reference image used by the IC-LoRA Union node for style/character anchoring. - **`video_strength`** (`float`, _optional_): Video conditioning strength. Lower values give the model more freedom to change the reference video motion/structure. Default value: `0.6` - Default: `0.6` - Range: `0` to `1` - **`num_frames`** (`integer`, _optional_): The number of frames to generate. Default value: `121` - Default: `121` - Range: `9` to `481` - **`resolution`** (`ImageSize | Enum`, _optional_): The size of the generated video. 'auto' keeps the official Union Control workflow's low-resolution control output size, while an explicit size requests a larger generated output. Default value: `auto` - Default: `"auto"` - One of: ImageSize | Enum - **`frames_per_second`** (`float`, _optional_): Frames per second of the generated video. Default value: `24` - Default: `24` - Range: `1` to `60` - **`num_inference_steps`** (`integer`, _optional_): Number of inference steps. Defaults to 15 for this distilled ComfyUI workflow and can be increased up to 30. Default value: `15` - Default: `15` - Range: `8` to `30` - **`guidance_scale`** (`float`, _optional_): Classifier-free guidance scale. The default follows the distilled LTX-2.3 workflow. Default value: `1` - Default: `1` - Range: `1` to `20` - **`generate_audio`** (`boolean`, _optional_): Whether to include audio in the returned video. When disabled, the final MP4 is returned without an audio track. Default value: `true` - Default: `true` - **`negative_prompt`** (`string`, _optional_): The negative prompt to steer generation away from. Default value: `"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"` - Default: `"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"` - **`seed`** (`integer`, _optional_): Random seed for reproducibility. If None, a random seed is chosen. - **`enable_prompt_expansion`** (`boolean`, _optional_): Whether to enable prompt expansion. Default value: `true` - Default: `true` - **`enable_safety_checker`** (`boolean`, _optional_): Whether to enable the safety checker. Default value: `true` - Default: `true` - **`video_quality`** (`VideoQualityEnum`, _optional_): The quality preset of the generated video. Default value: `"high"` - Default: `"high"` - Options: `"low"`, `"medium"`, `"high"`, `"maximum"` - **`video_write_mode`** (`VideoWriteModeEnum`, _optional_): The write mode of the generated video. Default value: `"balanced"` - Default: `"balanced"` - Options: `"fast"`, `"balanced"`, `"small"` - **`sync_mode`** (`boolean`, _optional_): If True, the media is returned as a data URI inline in the response. Useful for short-lived requests and tests. - Default: `false` **Required Parameters Example**: ```json { "prompt": "A dancer in a flowing red dress against a black backdrop, studio lighting, cinematic.", "video_url": "https://v3b.fal.media/files/b/0a8824b1/sdm0KfmenrlywesfzY1Y1_if6euPp1.mp4" } ``` **Full Example**: ```json { "prompt": "A dancer in a flowing red dress against a black backdrop, studio lighting, cinematic.", "video_url": "https://v3b.fal.media/files/b/0a8824b1/sdm0KfmenrlywesfzY1Y1_if6euPp1.mp4", "video_strength": 0.6, "num_frames": 121, "resolution": "auto", "frames_per_second": 24, "num_inference_steps": 15, "guidance_scale": 1, "generate_audio": true, "negative_prompt": "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", "enable_prompt_expansion": true, "enable_safety_checker": true, "video_quality": "high", "video_write_mode": "balanced" } ``` ### Output Schema The API returns the following output format: - **`video`** (`File`, _required_): The generated video. - **`seed`** (`integer`, _required_): The seed actually used for generation. - **`prompt`** (`string`, _required_): The prompt used for generation (after any expansion). **Example Response**: ```json { "video": { "url": "", "content_type": "image/png", "file_name": "z9RV14K95DvU.png", "file_size": 4404019 }, "prompt": "" } ``` ## Usage Examples ### cURL ```bash curl --request POST \ --url https://fal.run/fal-ai/ltx-2.3-quality/reference-video-to-video \ --header "Authorization: Key $FAL_KEY" \ --header "Content-Type: application/json" \ --data '{ "prompt": "A dancer in a flowing red dress against a black backdrop, studio lighting, cinematic.", "video_url": "https://v3b.fal.media/files/b/0a8824b1/sdm0KfmenrlywesfzY1Y1_if6euPp1.mp4" }' ``` ### Python Ensure you have the Python client installed: ```bash pip install fal-client ``` Then use the API client to make requests: ```python import fal_client def on_queue_update(update): if isinstance(update, fal_client.InProgress): for log in update.logs: print(log["message"]) result = fal_client.subscribe( "fal-ai/ltx-2.3-quality/reference-video-to-video", arguments={ "prompt": "A dancer in a flowing red dress against a black backdrop, studio lighting, cinematic.", "video_url": "https://v3b.fal.media/files/b/0a8824b1/sdm0KfmenrlywesfzY1Y1_if6euPp1.mp4" }, with_logs=True, on_queue_update=on_queue_update, ) print(result) ``` ### JavaScript Ensure you have the JavaScript client installed: ```bash npm install --save @fal-ai/client ``` Then use the API client to make requests: ```javascript import { fal } from "@fal-ai/client"; const result = await fal.subscribe("fal-ai/ltx-2.3-quality/reference-video-to-video", { input: { prompt: "A dancer in a flowing red dress against a black backdrop, studio lighting, cinematic.", video_url: "https://v3b.fal.media/files/b/0a8824b1/sdm0KfmenrlywesfzY1Y1_if6euPp1.mp4" }, logs: true, onQueueUpdate: (update) => { if (update.status === "IN_PROGRESS") { update.logs.map((log) => log.message).forEach(console.log); } }, }); console.log(result.data); console.log(result.requestId); ``` ## Additional Resources ### Documentation - [Model Playground](https://fal.ai/models/fal-ai/ltx-2.3-quality/reference-video-to-video) - [API Documentation](https://fal.ai/models/fal-ai/ltx-2.3-quality/reference-video-to-video/api) - [OpenAPI Schema](https://fal.ai/api/openapi/queue/openapi.json?endpoint_id=fal-ai/ltx-2.3-quality/reference-video-to-video) ### fal.ai Platform - [Platform Documentation](https://docs.fal.ai) - [Python Client](https://docs.fal.ai/clients/python) - [JavaScript Client](https://docs.fal.ai/clients/javascript)