Black Forest Labs Flux 3 Start End To Video Draft

Black Forest Labs Flux 3 Start End To Video Draft

Playground

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.

Features

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

Key Capabilities

• Create quick transition previews between a start image and an end image.
• Test subject movement, transformations, camera paths, environment changes, and pacing.
• Optionally generate synchronized audio for early transition and sound tests.
• Choose a duration from 5 to 20 seconds.
• Support landscape, portrait, square, and cinematic aspect ratios.

Parameters

How to Use

1. Provide the image that should appear at the beginning of the transition.
2. Provide the image that should appear at the end of the transition.
3. Describe the movement, transformation, camera path, and pacing between the keyframes.
4. Choose the aspect ratio and duration for the draft preview.
5. Enable generate_audio when you want to test matching ambience, effects, music, or dialogue.

Prompting Tips

• Describe the visual path from the start image to the end image rather than listing unrelated scenes.
• Explain what moves, transforms, appears, disappears, or changes between the keyframes.
• Use camera directions such as dolly-in, pull-back, orbit, tracking shot, or crane movement.
• Start with a simple transition, then refine the prompt after reviewing the first draft.

Pricing

Billing Rules

• The billed duration is rounded up to the next whole second.
• The minimum billed duration is 5 seconds.
• The maximum billed duration is 20 seconds.
• Audio generation does not add a separate charge in the current pricing formula.
• Example: a 5-second draft costs $0.30.
• Example: a 10-second draft costs $0.60.

Best Use Cases

• Product reveals, logo transitions, and before-and-after concepts.
• Character transformations and outfit or environment changes.
• Keyframe-based story moments and social-media transitions.
• Quickly comparing different motion paths between two defined states.

Notes

• Prompt, start_image, and end_image are required.
• Use visually compatible start and end images when you want a smoother transition.
• Draft outputs are intended for exploration and iteration.

Authentication

For authentication details, please refer to the Authentication Guide.

API Endpoints

Submit Task & Query Result

set -euo pipefail

export WAVESPEED_API_KEY="your-api-key"

REQUEST_BODY=$(cat <<'JSON'
{
  "prompt": "A cinematic ocean wave at sunrise, highly detailed",
  "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",
  "resolution": "720p",
  "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 "Authorization: Bearer ${WAVESPEED_API_KEY}" \
  -H "Content-Type: application/json" \
  -d "${REQUEST_BODY}")

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

# 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' "${RESPONSE}" | jq 'if type == "object" and has("data") then .data else . end')
  STATUS=$(printf '%s' "${RESULT}" | jq -r '.status // empty')

  case "${STATUS}" in
    completed) printf '%s\n' "${RESULT}" | jq '.outputs'; break ;;
    failed|cancelled|timeout) printf '%s\n' "${RESULT}" | jq . >&2; exit 1 ;;
    created|processing) sleep 2 ;;
    *) printf 'Unexpected status: %s
' "${STATUS}" >&2; exit 1 ;;
  esac
done

Parameters

Task Submission Parameters

Request Parameters

Response Parameters

Result Request Parameters

Result Response Parameters