Alibaba Happyhorse 1.0 Video Extend

Alibaba Happyhorse 1.0 Video Extend

Playground

Alibaba Happy Horse 1.0 (Video Extend) extends existing videos with seamless AI-generated continuation, supporting 720p/1080p output. Ready-to-use REST API, best performance, no coldstarts, affordable pricing.

Features

Alibaba Happy Horse 1.0 Video Extend continues an existing video clip with new AI-generated footage, seamlessly extending the scene from where the original ends. Upload a source video, describe how the video should continue, and the model generates a coherent continuation in 720p or 1080p.

• Need to edit an existing clip instead of extending it? Try Alibaba Happy Horse 1.0 Video Edit.
• Need to generate a new video from text? Try Alibaba Happy Horse 1.0 Text-to-Video.

Why Choose This?

• Seamless video continuation Extend an existing clip with newly generated footage that picks up naturally from the original ending.

• Prompt-guided scene progression Describe how the action, camera movement, atmosphere, or story should continue using natural language.

• Cinematic motion Generate smooth, expressive motion while preserving the overall feel and flow of the source video.

• Flexible resolution options Choose 720p for lower-cost iteration or 1080p for higher-quality final output.

• Production-ready API Access the model through a REST inference API with no cold starts for scalable integration into creative workflows.

Parameters

How to Use

1. Upload your source video — provide the clip you want to continue.
2. Write your prompt — describe how the scene, subject, camera, or atmosphere should progress after the original ending.
3. Choose resolution — use 720p for lower-cost iteration or 1080p for higher-quality results.
4. Set duration — choose the total output duration between 3 and 15 seconds.
5. Set a seed (optional) — use a fixed seed if you want more reproducible results.
6. Submit — generate and download the extended video.

Example Prompt

Continue the scene with a slow forward camera movement, the subject walking deeper into the alley, soft rain beginning to fall, stronger reflections on the ground, and a cinematic moody nighttime atmosphere

Pricing

Per 5 Seconds

Example Costs

Billing Rules

• Base price: 720p costs $0.70 per 5 seconds
• 1080p surcharge: 1080p costs 2× the 720p rate
• Total price formula:
  total_price = 0.70 × (resolution == "1080p" ? 2 : 1) × duration / 5

Best Use Cases

• Scene continuation — Extend cinematic clips with natural motion and coherent progression.
• Storyboarding and concept work — Explore how a shot or sequence might continue without manual video production.
• Ad creative development — Expand short promo clips into longer variations for campaigns and testing.
• Social media content — Create longer edits from short source footage for platform-specific needs.
• Atmospheric scene building — Continue motion, lighting, and mood from an existing clip into a richer sequence.
• Creative prototyping — Quickly test alternate continuations before investing in full production.

Pro Tips

• Use a source video with a clear ending frame for smoother continuation.
• Be explicit about what should happen next, including subject action, camera motion, lighting, and atmosphere.
• Keep prompts visually concrete, such as “camera slowly pushes in,” “the subject turns and walks away,” or “fog begins to roll in.”
• Use 720p for quick testing, then switch to 1080p for final-quality output.
• Reuse the same seed when you want more reproducible generations.
• Start with shorter durations to validate continuity before generating longer clips.

Notes

• Both video and prompt are required.
• Ensure video URLs are publicly accessible.
• Supported resolutions are 720p and 1080p.
• Supported total output duration is 3–15 seconds.
• Pricing scales linearly with duration.
• 1080p pricing is exactly 2× the 720p rate.

Related Models

• Alibaba Happy Horse 1.0 Video Edit — Perform prompt-driven editing on existing videos.
• Alibaba Happy Horse 1.0 Text-to-Video — Generate cinematic videos directly from natural-language prompts.
• Alibaba Happy Horse 1.0 Image-to-Video — Animate a single reference image into a cinematic clip.

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",
  "video": "https://interactive-examples.mdn.mozilla.net/media/cc0-videos/flower.mp4",
  "resolution": "720p",
  "duration": 5
}
JSON
)

# 1. Submit the prediction.
SUBMIT_RESPONSE=$(curl --silent --show-error --fail-with-body \
  -X POST "https://api.wavespeed.ai/api/v3/alibaba/happyhorse-1.0/video-extend" \
  -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