Seedance 1.5 Pro Video Extend | AI Video Extender

ByteDance Seedance V1.5 Pro — Video Extend

Seedance V1.5 Pro (Video Extend) extends an existing video into a longer clip while preserving motion continuity, subject identity, and scene coherence. Use a prompt to guide what happens next, set duration and resolution, and optionally enable audio generation for the extended segment.

Why it stands out

Smooth continuation that matches the original clip’s rhythm and aesthetics
Prompt-guided extension to steer action, mood, and camera behavior
Resolution options with transparent multipliers (480p / 720p)
Optional audio generation with clear pricing impact

Key Capabilities

Natural motion continuation Extends movement with consistent pacing and visual logic.
Scene coherence preservation Maintains lighting, framing, and subject consistency across the extension.
Prompt-guided direction Describe the next action and constraints without rebuilding the scene.
Optional audio generation Enable or disable audio generation depending on your workflow needs.

Parametrs

Parameter	Description
video*	Input video (public URL or uploaded file reference, depending on client).
prompt*	Describe what should happen next and what must remain consistent.
duration	Output duration in seconds (commonly used values: 4–12s; exact allowed values depend on endpoint validation).
resolution	Output resolution: 720p or 480p.
generate_audio	Whether to generate audio for the output video (true/false).
camera_fixed	Whether to fix the camera position (true/false).
seed	Random seed (-1 for random; set a fixed integer for reproducible results).

Prompt Tips

Write prompts like a continuation brief:

Describe what happens next (action + timing)
Add motion intensity (subtle / smooth / dynamic)
Specify camera behavior if needed (fixed / slow pan / gentle zoom)
Add constraints: “keep the same character, outfit, lighting, framing”

Example prompts:

Continue the scene with the subject holding the glowing ball, the light intensifies near the end, keep the same camera angle and lighting style.
Extend with subtle hand movement and a slow push-in, keep the subject centered and the environment unchanged.

Pricing

Reference pricing (generate_audio = true)

Resolution	Price per second	Example (5s)	Example (10s)
720p	$0.052	$0.26	$0.52
480p	$0.024	$0.12	$0.24

Reference pricing (generate_audio = false)

Resolution	Price per second	Example (5s)	Example (10s)
720p	$0.026	$0.13	$0.26
480p	$0.012	$0.06	$0.12

Best Practices

Use clean input videos (clear subject, stable exposure, minimal compression artifacts).
Keep prompts specific but short, and explicitly state what must stay the same.
Start with 5 seconds to validate motion and framing before extending longer.
Use a fixed seed when iterating to compare small prompt changes.

Use Cases

Ad creative extension (turn short shots into longer deliverables)
Social content variations (longer cuts from a base clip)
Storytelling continuity (extend key moments with controlled motion)
Marketing edits (extend hero scenes with stable aesthetics)

Notes

The input video must be accessible to the runtime (public URL or valid uploaded reference).
If motion drifts or the scene changes too much, add stronger constraints: “keep camera fixed”, “same outfit and lighting”, “do not change background”.
Supported durations and modes can vary by deployment; rely on the endpoint UI/validator for exact allowed values.

Related Models

Seedance V1.5 Pro Video Extend Fast — Faster processing with higher-resolution options for rapid iteration and production outputs.
Seedance V1.5 Pro (Text-to-Video) — Generate new videos from text prompts for end-to-end creation.
Seedance V1.5 Pro (Image-to-Video) — Animate still images into videos with guided motion and stable aesthetics.

ExamplesView all

README