# Flux 3 First Last Frame to Video > FLUX.3 is Black Forest Labs' frontier video model. This endpoint generates the video between a defined start and end frame, interpolating a smooth, coherent transition from the first image to the last. ## Overview - **Endpoint**: `https://fal.run/blackforestlabs/flux-3/first-last-frame-to-video` - **Model ID**: `blackforestlabs/flux-3/first-last-frame-to-video` - **Category**: image-to-video - **Kind**: inference **Tags**: stylized, transform, lipsync ## Pricing Your request will be charged at **0.17** $ per second of generated video at 720p, and **0.29** $ per second at 1080p. 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 text prompt describing the video you want to generate. - Examples: "A red panda walks along a mossy log in a sunlit forest, one continuous unbroken shot. Ambient birdsong and rustling leaves." - **`aspect_ratio`** (`AspectRatioEnum`, _optional_): Aspect ratio of the generated video. `auto` lets the model choose. Default value: `"auto"` - Default: `"auto"` - Options: `"auto"`, `"21:9"`, `"2:1"`, `"16:9"`, `"4:3"`, `"1:1"`, `"3:4"`, `"9:16"` - **`resolution`** (`ResolutionEnum`, _optional_): Resolution of the generated video. Default value: `"720p"` - Default: `"720p"` - Options: `"720p"`, `"1080p"` - **`duration`** (`DurationEnum`, _optional_): Duration of the generated video in seconds. An explicit duration is required to place the end frame. Default value: `"5"` - Default: `5` - Options: `5`, `6`, `7`, `8`, `9`, `10`, `11`, `12`, `13`, `14`, `15`, `16`, `17`, `18`, `19`, `20` - **`generate_audio`** (`boolean`, _optional_): Whether to generate audio for the video. Default value: `true` - Default: `true` - **`safety_tolerance`** (`integer`, _optional_): The safety tolerance level for the generated video. 0 is the strictest and 4 is the most permissive. Default value: `2` - Default: `2` - Range: `0` to `4` - **`start_image_url`** (`string`, _required_): URL of the image used as the first frame of the video (PNG, JPEG, or WebP). - Examples: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg" - **`end_image_url`** (`string`, _required_): URL of the image used as the last frame of the video (PNG, JPEG, or WebP). - Examples: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg" **Required Parameters Example**: ```json { "prompt": "A red panda walks along a mossy log in a sunlit forest, one continuous unbroken shot. Ambient birdsong and rustling leaves.", "start_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg", "end_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg" } ``` **Full Example**: ```json { "prompt": "A red panda walks along a mossy log in a sunlit forest, one continuous unbroken shot. Ambient birdsong and rustling leaves.", "aspect_ratio": "auto", "resolution": "720p", "duration": 5, "generate_audio": true, "safety_tolerance": 2, "start_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg", "end_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg" } ``` ### Output Schema The API returns the following output format: - **`video`** (`File`, _required_): The generated video. - Examples: {"url":"https://storage.googleapis.com/falserverless/example_outputs/veo3-i2v-output.mp4"} - **`seed`** (`integer`, _required_): The seed used for the generation. **Example Response**: ```json { "video": { "url": "https://storage.googleapis.com/falserverless/example_outputs/veo3-i2v-output.mp4" } } ``` ## Usage Examples ### cURL ```bash curl --request POST \ --url https://fal.run/blackforestlabs/flux-3/first-last-frame-to-video \ --header "Authorization: Key $FAL_KEY" \ --header "Content-Type: application/json" \ --data '{ "prompt": "A red panda walks along a mossy log in a sunlit forest, one continuous unbroken shot. Ambient birdsong and rustling leaves.", "start_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg", "end_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg" }' ``` ### 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( "blackforestlabs/flux-3/first-last-frame-to-video", arguments={ "prompt": "A red panda walks along a mossy log in a sunlit forest, one continuous unbroken shot. Ambient birdsong and rustling leaves.", "start_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg", "end_image_url": "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg" }, 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("blackforestlabs/flux-3/first-last-frame-to-video", { input: { prompt: "A red panda walks along a mossy log in a sunlit forest, one continuous unbroken shot. Ambient birdsong and rustling leaves.", start_image_url: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-1.jpeg", end_image_url: "https://storage.googleapis.com/falserverless/example_inputs/veo31-flf2v-input-2.jpeg" }, 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/blackforestlabs/flux-3/first-last-frame-to-video) - [API Documentation](https://fal.ai/models/blackforestlabs/flux-3/first-last-frame-to-video/api) - [OpenAPI Schema](https://fal.ai/api/openapi/queue/openapi.json?endpoint_id=blackforestlabs/flux-3/first-last-frame-to-video) ### fal.ai Platform - [Platform Documentation](https://fal.ai/docs/documentation) - [Python Client](https://fal.ai/docs/api-reference/client-libraries/python) - [JavaScript Client](https://fal.ai/docs/api-reference/client-libraries/javascript)