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FLUX 3 Start-End-to-Video Draft quickly generates a transition between required start and end images, with prompt-guided motion, optional synchronized audio, and flexible 5-20 second duration for rapid keyframe iteration.

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$0.3per run·~33 / $10

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He carefully adds buildings, trees and streetlights piece by piece. The camera shows his hands and smooth overhead views of the growing town. Tiny lights gradually turn on across the miniature streets, and the final shot pulls back as a small train begins moving around the completed model. He also grows from a kid to a man.

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README

FLUX 3 Draft Start-End-to-Video

FLUX 3 Draft Start-End-to-Video quickly generates a transition between a required starting image and a required ending image. Use it to test action, transformation, camera movement, pacing, and visual style between two keyframes before moving to a final-quality workflow.

Why Choose This?

  • Start-and-end-frame control
    Generate a video transition from a defined first frame to a defined final frame.

  • Fast transition preview
    Quickly test movement, transformation, camera paths, environment changes, and pacing.

  • Prompt-guided motion
    Describe how the subject, scene, lighting, and camera should evolve between the two keyframes.

  • Optional synchronized audio
    Generate matching audio for early sound, ambience, effects, music, or dialogue tests.

  • Flexible duration
    Choose a draft video duration from 5 to 20 seconds.

  • Multiple aspect ratios
    Supports landscape, portrait, square, and cinematic formats.

Parameters

ParameterRequiredDescription
promptYesDescribe the action or transformation connecting the start and end images, including camera movement, timing, mood, lighting, and style.
start_imageYesImage used as the first visual keyframe.
end_imageYesImage used as the final visual keyframe.
aspect_ratioNoOutput aspect ratio. Options: 21:9, 2:1, 16:9, 4:3, 1:1, 3:4, or 9:16.
durationNoDraft video duration in seconds. Range: 5–20. Default: 5.
generate_audioNoGenerate synchronized audio for the draft transition. Default: true.

How to Use

  1. Upload the start image — Provide the image that should appear at the beginning of the transition.
  2. Upload the end image — Provide the image that should appear at the end of the transition.
  3. Write the prompt — Describe the movement, transformation, camera path, timing, and style between the two keyframes.
  4. Choose aspect ratio — Select the output format that matches your target use case.
  5. Set duration — Choose a draft duration from 5 to 20 seconds.
  6. Configure audio optional — Enable generate_audio when you want to test ambience, effects, music, or dialogue.
  7. Submit — Generate the draft transition video.

Pricing

Pricing is based on billed video duration.

Billed duration is rounded up to the next whole second and capped at 20 seconds. The API accepts durations from 5 to 20 seconds. Audio generation does not add a separate charge.

Billing UnitPrice
Per 5s$0.30
Per second$0.06

Example Costs

DurationBilled DurationCost
5s5s$0.30
10s10s$0.60
15s15s$0.90
20s20s$1.20

Best Use Cases

  • Product reveals — Transition from a hidden or simple product setup to a polished reveal.
  • Before-and-after concepts — Show visual transformation between two defined states.
  • Character transformations — Animate outfit, pose, style, or environment changes between keyframes.
  • Logo and brand transitions — Create fast previews for motion branding and visual identity work.
  • Story keyframes — Connect two planned story moments with controlled motion and pacing.
  • Social media transitions — Generate short transition clips for vertical, square, or widescreen content.

Pro Tips

  • Use visually compatible start and end images when you want a smoother transition.
  • Describe the path from the start image to the end image instead of listing unrelated scenes.
  • Explain what moves, transforms, appears, disappears, or changes between the keyframes.
  • Add camera directions such as dolly-in, pull-back, orbit, tracking shot, or crane movement.
  • Keep the first test simple, then refine the prompt after reviewing the draft output.
  • Use shorter durations for quick iteration and longer durations when the transition needs more time to unfold.

Related Models

Note:This website uses AI models provided by third parties. Documentation prices are for reference and may be outdated. The Generate button shows an estimate; the final task charge prevails.

Flux 3 Start End To Video Draft API — Quick start

Grab a WaveSpeedAI API key, then call POST https://api.wavespeed.ai/api/v3/black-forest-labs/flux-3/start-end-to-video-draft with your input as JSON. The endpoint returns a prediction id. Start polling the result endpoint around every 2 seconds, increase the interval for long-running tasks, and stop on any terminal status. On completed, read output values from data.outputs. Examples for Flux 3 Start End To Video Draft below.

HTTP example
set -euo pipefail

: "${WAVESPEED_API_KEY:?Set WAVESPEED_API_KEY}"

REQUEST_BODY=$(cat <<'JSON'
{
    "prompt": "A cinematic shot of a city at sunset, soft golden light",
    "start_image": "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg",
    "end_image": "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg",
    "aspect_ratio": "21:9",
    "duration": 5,
    "generate_audio": true
}
JSON
)

# 1. Submit the prediction.
SUBMIT_RESPONSE=$(curl --silent --show-error --fail-with-body \
  -X POST "https://api.wavespeed.ai/api/v3/black-forest-labs/flux-3/start-end-to-video-draft" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $WAVESPEED_API_KEY" \
  -d "$REQUEST_BODY")

TASK=$(printf '%s' "$SUBMIT_RESPONSE" | jq 'if has("data") then .data else . end')
PREDICTION_ID=$(printf '%s' "$TASK" | jq -r '.id')
if [ -z "$PREDICTION_ID" ] || [ "$PREDICTION_ID" = "null" ]; then
  printf 'Submission response did not contain a prediction id
' >&2
  exit 1
fi
RESULT_URL="https://api.wavespeed.ai/api/v3/predictions/$PREDICTION_ID/result"

# 2. Poll until the prediction finishes.
while true; do
  RESPONSE=$(curl --silent --show-error --fail-with-body "$RESULT_URL" \
    -H "Authorization: Bearer $WAVESPEED_API_KEY")
  RESULT=$(printf '%s' "$RESPONSE" | jq 'if has("data") then .data else . end')
  STATUS=$(printf '%s' "$RESULT" | jq -r '.status')
  case "$STATUS" in
    completed) printf '%s\n' "$RESULT" | jq '.outputs'; break ;;
    failed|cancelled|timeout|deleted) printf '%s\n' "$RESULT" | jq . >&2; exit 1 ;;
    *) sleep 2 ;;
  esac
done
Node.js example
const submitUrl = "https://api.wavespeed.ai/api/v3/black-forest-labs/flux-3/start-end-to-video-draft";
const apiKey = process.env.WAVESPEED_API_KEY;
if (!apiKey) throw new Error('Set WAVESPEED_API_KEY');

async function requestJson(url, options = {}) {
  const response = await fetch(url, options);
  if (!response.ok) throw new Error(await response.text());
  return response.json();
}

// 1. Submit the prediction.
const body = await requestJson(submitUrl, {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${apiKey}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
        "prompt": "A cinematic shot of a city at sunset, soft golden light",
        "start_image": "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg",
        "end_image": "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg",
        "aspect_ratio": "21:9",
        "duration": 5,
        "generate_audio": true
}),
});
const task = body.data ?? body;
if (!task.id) throw new Error("Submission response did not contain a prediction id");
const resultUrl = `https://api.wavespeed.ai/api/v3/predictions/${task.id}/result`;

// 2. Poll until the prediction finishes.
while (true) {
  const resultBody = await requestJson(resultUrl, {
    headers: { "Authorization": `Bearer ${apiKey}` },
  });
  const result = resultBody.data ?? resultBody;
  if (result.status === "completed") {
    console.log(result.outputs);
    break;
  }
  if (["failed", "cancelled", "timeout", "deleted"].includes(result.status)) throw new Error(JSON.stringify(result));
  await new Promise(resolve => setTimeout(resolve, 2000));
}
Python example
import json
import os
import time
from urllib.request import Request, urlopen

api_key = os.environ["WAVESPEED_API_KEY"]
headers = {"Authorization": f"Bearer {api_key}", "Content-Type": "application/json"}
payload = {
    "prompt": "A cinematic shot of a city at sunset, soft golden light",
    "start_image": "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg",
    "end_image": "https://interactive-examples.mdn.mozilla.net/media/cc0-images/painted-hand-298-332.jpg",
    "aspect_ratio": "21:9",
    "duration": 5,
    "generate_audio": True
}

def request_json(url, data=None):
    request = Request(url, data=data, headers=headers, method="POST" if data else "GET")
    with urlopen(request) as response:
        return json.load(response)

# 1. Submit the prediction.
body = request_json("https://api.wavespeed.ai/api/v3/black-forest-labs/flux-3/start-end-to-video-draft", json.dumps(payload).encode())
task = body.get("data", body)
if not task.get("id"):
    raise RuntimeError("Submission response did not contain a prediction id")
result_url = f"https://api.wavespeed.ai/api/v3/predictions/{task['id']}/result"

# 2. Poll until the prediction finishes.
while True:
    result_body = request_json(result_url)
    result = result_body.get("data", result_body)
    status = result.get("status")
    if status == "completed":
        print(result.get("outputs", []))
        break
    if status in {"failed", "cancelled", "timeout", "deleted"}:
        raise RuntimeError(result)
    time.sleep(2)

Flux 3 Start End To Video Draft API — Frequently asked questions

What is the Flux 3 Start End To Video Draft API?

Flux 3 Start End To Video Draft is a Black Forest Labs model for video generation from images, exposed as a REST API on WaveSpeedAI. FLUX 3 Start-End-to-Video Draft quickly generates a transition between required start and end images, with prompt-guided motion, optional synchronized audio, and flexible 5-20 second duration for rapid keyframe iteration. You can call it programmatically or try it from the playground above.

How do I call the Flux 3 Start End To Video Draft API?

POST your input parameters to the model's REST endpoint (shown in the API tab of this playground) with your WaveSpeedAI API key in the Authorization header. Submission returns a prediction ID. Poll the result endpoint starting around every 2 seconds, increase the interval for long-running tasks, and stop on any terminal status. The playground generates Python, JavaScript, and cURL examples for submitting requests and polling results. Full request/response shape is documented at https://wavespeed.ai/docs/docs-api/black-forest-labs/black-forest-labs-flux-3-start-end-to-video-draft.

How much does Flux 3 Start End To Video Draft cost per run?

Flux 3 Start End To Video Draft starts at $0.3 per run. That figure is the base price — the final charge scales with the parameters you set in the form (output size, length, count, references, or whatever knobs this model exposes), so a higher-quality or larger output costs more than a minimal one. The exact cost for your current input is shown live next to the Generate button before you submit, and the actual per-call charge is recorded on the prediction afterwards.

What inputs does Flux 3 Start End To Video Draft accept?

Key inputs: `prompt`, `aspect_ratio`, `duration`, `end_image`, `generate_audio`, `start_image`. The full JSON schema (types, defaults, allowed values) is rendered above the Generate button and mirrored in the API reference at https://wavespeed.ai/docs/docs-api/black-forest-labs/black-forest-labs-flux-3-start-end-to-video-draft.

How long does Flux 3 Start End To Video Draft take to generate?

Reported generation time on WaveSpeedAI is around 87 seconds per request. This is an estimate, not a latency guarantee; queue time and input settings can change the total wait. live status is visible in the prediction record.

Can I use Flux 3 Start End To Video Draft outputs commercially?

Commercial usage rights depend on the model's license, set by its provider (Black Forest Labs). Check the provider's applicable terms and WaveSpeedAI's Terms of Service before commercial use.