How to extend AI video, edit a clip or restyle it without starting over
The clip is nearly right: it needs four more seconds, a red jacket instead of a blue one, or the same motion in a different style. You do not have to regenerate. Here is how Extend, Edit, Morph restyle and Motion control work, what each costs, and when it is cheaper to start again.
· 6 min read · 1.2K views · by the Cortex Digital Hub team
Drop the clip you already made into Extend, Edit or Motion control and describe only the change. You are billed on the input length plus any new seconds, so trim the clip first. From ₹24 a clip · no watermark · runs in your browser
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The clip is almost right. The camera move is the one you wanted, the product looks like your product, and it ends two seconds too early, or the host is in a blue jacket when the brand colour is red. Regenerating throws away the part that worked and gives you a new set of problems. The AI Video Generator has four ways to fix a clip without starting over, and each one is billed differently, so it is worth knowing them before you spend credits.
Extend: continue a clip by 4 to 30 seconds
Extend video takes a clip you have already made and continues it. The model looks at the last moments, reads your prompt for what happens next, and adds 4 to 30 seconds that pick up where the original left off. As of October 2026, Vela 2.5 is the model in the picker that supports it.
A 10-second clip of a kurta on a mannequin turning, and you want it to finish with the camera pulling back to show the full outfit: extend by 5 seconds with "the camera pulls back slowly to show the full length" and the turn you liked is untouched.
Billing is the catch. You pay for the input clip's length plus the new seconds, at the model's per-second rate. Extending a 10-second clip by 5 seconds on Vela 2.5 at 480p is 15 seconds x 77 credits, or 1,155 credits (₹577.50). Extending a 5-second clip by the same 5 seconds is 770 credits (₹385). So trim the input to the part the continuation actually needs before you upload it. The trim tool does that on your device, and the trim without re-encoding guide shows how to keep the frames sharp.
Edit: change the clip from a prompt
Edit video keeps the motion and changes what is in it. You open the clip, describe the change, and the model re-draws the frames with that change applied: "make it snow", "swap the jacket for a red one", "turn the afternoon into dusk", "put a bowl of fruit on the counter".
Models with edit as of October 2026 are Vela 2.5, Lumen Frames and Lumen Omni. Lumen Frames is the cheapest at 23 credits a second, so a 5-second edit is 115 credits (₹57.50); Lumen Omni is 150 for 5 seconds; Vela 2.5 at 480p is 385. Billing is on the input length again, so the same rule applies: cut to the seconds you want changed.
Edit works best when the change is on the surface: colour, weather, time of day, a prop, the material of a wall. It struggles when the change is structural, such as a different camera move, subject or framing, because the motion it is trying to keep no longer fits the new content. Save those for a fresh generation.
Keep the prompt to the change. The model already has the scene; "swap the jacket for a red one" is a complete instruction, and describing the rest of the room invites it to change the rest of the room.
Morph: restyle from reference images, keep the motion
Morph is the model built for a different kind of edit. Instead of a prompt, you give it reference images in the style you want, and it restyles the whole clip to match while keeping the original movement. A phone video of your Bangalore cafe becomes a watercolour; a walkthrough of a sample flat becomes a line-art animation for the brochure; a founder clip takes on the look of your brand illustrations.
Morph takes 1 to 30 seconds of input and costs 84 credits a second at 480p (420 for 5 seconds, ₹210), 180 at 720p and 431 at 1080p. The 1080p rate is steep, so draft at 480p, confirm the style is right, and run the final once. Two to four reference images that share a palette and line weight give a more even result than one; the same advice as for keeping a character consistent applies to keeping a style consistent.
Motion control: animate a still with your own footage
Motion control is the reverse of the others. Instead of fixing a generated clip, you start with a still image and a video you shot yourself, and the model gives the still the video's movement. Film yourself picking a bottle off a shelf, give the model your product shot, and the product performs the move. Film a slow walk across a room and give it a render of the clubhouse, and the camera walks through the render.
Lumen Motion 3 is the model with motion control, from 115 credits for 5 seconds at Standard to 185 at 1080p, billed on the input video's length. Shoot the guide video short, on a tripod if the camera should be still, and trim it to the exact move before uploading.
Eight recipes with model and cost
| Recipe | Mode | Model | Input | Credits (approx. ₹) |
|---|---|---|---|---|
| Add a 4-second pull-back to a 5 s product clip | Extend | Vela 2.5, 480p | 5 s + 4 s | 693 (₹347) |
| Stretch a 10 s reel to 30 s | Extend | Vela 2.5, 480p | 10 s + 20 s | 2,310 (₹1,155) |
| Make it snow in a 5 s street scene | Edit | Lumen Frames | 5 s | 115 (₹58) |
| Swap a blue jacket for red | Edit | Lumen Omni | 5 s | 150 (₹75) |
| Turn a 5 s day exterior into dusk | Edit | Vela 2.5, 480p | 5 s | 385 (₹193) |
| Restyle a 5 s shop video as an illustration | Morph | Morph, 480p | 5 s + 3 refs | 420 (₹210) |
| Animate a product still with a hand-gesture video | Motion control | Lumen Motion 3, Standard | 5 s guide video | 115 (₹58) |
| Walk a camera through a render using your own walk | Motion control | Lumen Motion 3, 1080p | 5 s guide video | 185 (₹93) |
Credits are 1 credit = ₹0.50, deducted when the job starts and returned automatically if the model fails or declines. The generate button shows the exact total before you commit, so treat the table as a guide and the button as the truth.
When to regenerate instead
Look at the second row of that table. Extending a 10-second clip to 30 seconds on Vela 2.5 costs 2,310 credits. A fresh 30-second clip on Orbit 3 at 480p costs 420, and on Orbit Prime at 720p it costs 1,350. If the original 10 seconds were not special, regenerate at the full length on a cheaper model and keep the extend budget for clips where the first part is the part you cannot reproduce.
The same logic applies to edits. Three rounds of "swap the jacket", "now make it dusk", "now add rain" on a 10-second Vela 2.5 clip cost more than a new clip with all three in the prompt. Batch the changes into one edit, or put them in the original prompt next time and draft on a cheap model until it is right.
Regenerate too when the problem is the subject, the camera or the framing. Edit keeps the motion, which is exactly what you do not want when the motion is wrong. And clips stay in your history for only seven days, so download anything you might want to extend or edit later. When the clip is finally right, the free video tools finish it on your device: resize to 9:16 with the video resizer, and compress it for WhatsApp with the 16 MB compressor before it goes to a channel partner or a customer group.
Frequently asked questions
How much longer can I extend an AI video?
Extend video continues a clip by 4 to 30 seconds in one pass. As of October 2026 Vela 2.5 is the model that offers it, and you are billed on the input clip's length plus the new seconds, so trim the input to the part you want continued first.
What can Edit video change in a clip?
Anything you can describe in a prompt while keeping the motion: weather, time of day, the colour of a garment, an object on a table. Morph goes further and restyles the whole clip from reference images, keeping the original movement.
Why is editing billed on the input length?
Because the model has to process every second you give it, not just the seconds that change. A 15-second input costs three times a 5-second one even if only the last two seconds are edited. Cut the clip to the part you need before you upload.
When should I regenerate instead of editing?
When the change is to the subject, the camera move or the framing rather than to the surface, or when extending would cost more than a fresh long clip on a cheaper model. The generate button shows the total either way, so compare before pressing.