Describe the next beat
Say what should happen after the source clip - the action, subject behaviour, and camera language. This gives the provider a useful direction without claiming that it will copy the original motion.
Example
An example of what this page produces.
AI Video Extender
Free AI video extender online
Upload a source clip and describe what happens next. 智擎云 generates a reference-guided AI video extension that matches the original style and motion. Free AI video extender online.
MP4 or MOV, 2-15s each, 15s total, up to 200MB. Requires R2 with a public domain - the model fetches the file over the network.
Model
New in 2.5: generate up to 30 seconds, guide motion with as many as 30 images, or start from audio alone.
Input modeReferences
Add at least one reference below. Images, videos, and audio can be used alone or combined.
Reference videos (optional) 0/10
MP4 or MOV, 2-30s each, 30s combined, up to 200MB. Requires R2 with a public domain - the model fetches the file over the network.
Reference audio (optional) 0/10
Seedance 2.5 accepts MP3 or WAV clips, 2-30s each and 30s combined. Audio-only reference is supported.
4s30s
Free credits are for a quick preview, not the final video. Use a short duration and lower resolution to check the subject, motion, and prompt. A fuller, more compelling final shot often needs a longer duration and higher supported resolution—use paid credits when your scene needs those settings.
Audio
With audio
Synchronized sound, voice and music
Maximum credits reserved:¥7.99
Your generated video appears here. Describe a shot and hit Generate.
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AI Video Extender
Extend video with AI by uploading a source clip and describing what happens next. 智擎云 creates a separate, reference-guided continuation rather than a frame-perfect native extension.
The source video is sent as reference input, not as an editable timeline or a guaranteed final-frame condition. Subject, style, motion, and fine detail can drift. Use a clear source ending, review each result, and only then decide whether to run another separate generation at the selected model, resolution, ratio, and duration.
- Source video as reference
- Newly generated continuation
- Review each step for drift
Continue Short AI Videos into Longer Sequences
The source clip provides visual reference; the prompt provides direction for the continuation.
Keep the source focused
A short reference with a clear subject and readable ending is easier to use than a long or heavily blurred clip. The provider accepts up to three reference videos within the configured total-duration limit.
Review before chaining
Each continuation is a new task. Check identity, lighting, motion, and the cut before using the result as inspiration for another generation.
What makes an extension work
Choose a source whose subject and final moment are easy to read. A stable ending can give the provider better visual context, but it is not a promise of a seamless join because the workflow uses reference-video generation rather than native frame extension.
Describe what happens next instead of pretending the original timeline is being edited: "she turns toward the window and the camera settles" is more useful than a claim that the exact motion will be preserved. Repeat the lighting, palette, and wardrobe details that matter, then inspect the new clip for drift.
Use a readable ending
A visible subject and a stable final moment provide clearer reference material. They improve the odds of a useful result but do not guarantee a seamless continuation.
Generate in reviewable steps
Shorter separate generations give you a checkpoint. Keep the outputs that work and revise the prompt when the subject, motion, or style drifts.
Model specifications
Seedance 2.5 AI video specifications on 智擎云
Published model limits, not marketing rounding. Every number below is enforced by the generator before your credits are reserved.
- 480p / 720p / 1080p
- Output resolutions on this model — up to 4K across 智擎云 models
- 4-30 sec
- Clip length per generation, at 24 fps
- Native audio
- Sound effects and ambience generated in sync
- 30 + 10 + 10
- Reference images, videos, and audio files per request
- 7 ratios
- Supported aspect ratios - Auto, 16:9, 4:3, 1:1, 3:4, 9:16, 21:9
- Commercial use with paid access
- Subject to the Terms of Service
Why creators use 智擎云 for AI video generation
The model is ByteDance's. What 智擎云 adds is what makes it usable at work: honest limits, honest billing, and output you are allowed to ship.
Text, images, and video in a single pass
Text, up to 30 reference images, 10 reference videos, and 10 audio references can guide one Seedance 2.5 generation instead of being stitched together afterwards.
Sound generated with the picture
When audio is enabled, Seedance 2.5 can generate footsteps, room tone, impacts, dialogue, and score with the video. Review timing and content before publishing, or switch audio off when the clip needs separate sound design.
Flexible ratios, up to 4K
One prompt covers a 9:16 vertical cut for Reels, a 16:9 master for YouTube, and a 21:9 anamorphic frame for a title sequence. Resolution runs from 480p to 4K, so the same take holds up on a cinema screen and on a phone.
Credits you can predict
The maximum credit reservation is calculated from the selected model, duration, resolution, ratio, and video-reference input, then shown before submission. A successful video job can settle lower from provider-reported usage; confirmed failed jobs return the reservation.
Built for efficient iteration
Use Mini for cost-efficient prompt exploration, Fast when you want a balance of generation speed and cost, and Seedance 2.5 when its longer duration or richer reference inputs fit the shot. Switching models starts a new generation, so results may vary.
Yours to sell
Content generated with a paid subscription or purchased credit pack may be used commercially under the Terms of Service. Content generated solely with free sign-up or promotional credits is for evaluation and personal use only.
How to Extend a Video with AI
Upload a source, describe the next beat, and review the new clip before doing anything else.
- 1
Choose the source clip
Upload a focused reference video that ends on a clear moment. The current workflow uses the clip as reference material, not as a frame-accurate edit source.
- 2
Describe what happens next
Write the new action and camera behaviour, plus the continuity details that should guide the model. Avoid promising that the original motion will be copied exactly.
- 3
Generate and review
Inspect the result at the cut. If it is useful, you can start another separate generation from a suitable reference; if it drifted, adjust the prompt and try again.
What Can You Create with an AI Video Extender?
Use this workflow when you have a source clip whose subject, look, or final moment should guide a newly generated follow-up.
Give a hero shot another beat
When a source clip has the right subject and look but needs a new moment, use it as reference and describe the action you want to explore next.
Explore a performance variation
Use the source as visual guidance for a reaction, gesture, or reveal, while expecting the generated performance and fine details to vary.
Create options for an edit
Generate separate follow-up options and choose the one that fits your edit. Do not treat the page as a guarantee of an exact-duration or frame-perfect continuation.
AI Video Extension FAQs
What is an AI video extender?
It is a guided workflow that accepts a source video as reference and generates a new clip based on a prompt for what happens next. It is not a frame-perfect native extension tool.
How long can I extend a clip?
Each extension is itself a generation of 4 to 15 seconds, and extensions can be chained. Shorter steps are recommended - they give you a checkpoint before drift accumulates.
Will the extension match the original exactly?
No exact match is guaranteed. The new clip is generated from the source-video reference, so identity, motion, lighting, audio, and fine details can change. A clear source ending may provide better guidance.
Can I extend a video I did not generate here?
Yes - upload it as a reference clip. Reference video is capped at three clips totalling fifteen seconds, so trim to the ending segment you actually want continued.
Why is there a visible seam?
A visible difference is expected when the provider interprets the source as reference material. Motion blur, fast camera movement, occlusion, or an unclear subject can make the change more noticeable; try a clearer source and a more specific prompt.
Does the extension include audio?
Audio can be generated per task when the model setting is enabled, but continuity with the source audio is not guaranteed. Describe the intended ambience and review the result before editing it into the source.
Explore more AI video tools
Each tool uses Seedance 2.5 for a different job. Move between them freely — your credits, history, and exports are shared.
Ready to put AI video into your content workflow?
Choose paid access when you need commercial-use eligibility, predictable generation costs, and credits restored after a failed or rejected job. One-time packs are available with no subscription.
- One-time credit packs never expire
- Commercial use with paid access
- Reserved credits restored if generation fails