# AI video character replacement: change the cast, keep the cut

Try fal Recast with an original puppet scene, compare what changes, and keep titles, audio and timing intact in an editable Voyager video project.

Author: John Holliman

Canonical: https://voyager.so/blog/ai-video-character-replacement

Published: 2026-10-02T10:13:52-07:00
Updated: 2026-10-02T10:13:52-07:00

The wave works. The camera move works. Then someone asks for a different character.

Starting over risks losing the performance you liked. AI video character replacement gives you another option: use the finished shot as a motion reference, supply the new character, and check what survives. That matters for a mascot refresh, a pitch with several casting directions, or a short story whose design changes after animation.

We made a felt courier at a midnight station, then asked fal Recast to change her hair and outfit. Here's the original beside the replacement.

![Original orange-coated felt courier and recast green-coated courier wave in the same station.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/comparison-poster-5591765615bfc343.webp)

[Animation: Original orange-coated felt courier and recast green-coated courier wave in the same station.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/comparison-6fb09b038fd100b7.mp4)

[Download GIF](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/comparison-6031d08a58b525d4.gif)

Both clips play at their original speed, cropped around the gesture. Watch when each hand lowers.

## Replace a character with fal Recast

[fal announced Recast](https://x.com/fal/status/2105758120794259807) on October 1. It uses H3 Max and accepts a source video plus reference images. Its promise is to preserve the performance, camera and shot structure while changing who's on screen. That's the promise to test, not something to assume from a good first frame.

Start with a short clip where the subject is visible and the gesture reads clearly. Our source is an AI-generated puppet scene, made from a Nano Banana 2 still and animated with H3 Max. The replacement is another original generated puppet, shown against a plain background.

![The replacement puppet has teal hair, a mustard beret and an emerald coat.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/reference-card-46ae32830ecd9101.webp)

Give the model one clear character reference; let the source video provide the performance.

Upload the original clip as **Video URL** and the replacement image under **Reference Image URLs** in the [Recast playground](https://fal.ai/models/minimax/h3-max/recast). We used 1080P and this prompt:

```text
Replace the single felt courier with the felt woman from the reference image: teal bob haircut, mustard beret, emerald coat, ivory scarf, plum trousers, burgundy boots. Preserve her waving performance, her original ochre suitcase, the miniature railway station, warm lighting, camera movement and shot timing. Keep the handcrafted felt stop-motion style. No new text or characters.
```

Notice the split: name the character details that change, then name the performance and objects that matter. A vague request to “make another version” gives the model less guidance about what you already like.

Recast currently accepts videos from 5 to 30 seconds, with each shot no longer than 15 seconds. At the listed rates, five seconds costs $1.50 at 768p or $2.25 at 1080p, excluding source generation. [API documentation](https://fal.ai/models/minimax/h3-max/recast/api)

## Check the performance, not just the new face

The new puppet kept her teal hair, beret and green coat through the shot. The station and suitcase remained recognizable, and both videos contained 124 frames at 24 fps.

But the performance was not frame-exact: **the replacement held her raised hand longer**. The small shoulder bag also disappeared. For this quiet goodbye, the new take works; for a gesture timed to a musical hit or a continuity-critical prop, those differences would matter.

Scrub source and result at matching times. Check the raised hand, the suitcase handle, the subject's outline and a fixed background feature. Then check duration and the ending. A convincing portrait is not enough if the hand arrives late or the scene changes around it.

Keep titles, logos and subtitles outside the video you send to the model. They are exact design elements, and you can preserve them in your editor instead of asking a generator to redraw them.

## Keep the approved edit in Voyager

Once the new shot works, the next job is putting it into the existing deliverable. We used Voyager's native Video engine to keep the title overlay, original ambience and closing card on separate timeline clips.

![The revised felt-puppet film retains its title and closing card.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/film-poster-5ddc75bc6f90478b.webp)

[Video: The revised felt-puppet film retains its title and closing card.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/recast-film-581eb54ef53e6835.mp4)

The seven-second edit uses the replacement shot with the original title timing, ambience track and ending.

The green-coated courier waves. The Last Train title appears over the shot. The film ends on a card reading A different face. The same goodbye.

```text
Replace the performance clip in last-train-original.vvideo with recast.mp4. Keep its five-second source range, the title overlay, original audio and closing card unchanged. Save the original version. Render the revised seven-second film and show the timeline diff so I can verify what changed.
```

![Voyager plays the revised puppet film beside the agent’s timeline comparison.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/desktop-poster-ee10149eaaa649cf.webp)

[Video: Voyager plays the revised puppet film beside the agent’s timeline comparison.](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/desktop-demo-5e1e4b4b78b467fe.mp4)

Inside Voyager: the rendered revision plays beside the source replacement and preserved timeline elements. Silent desktop excerpt.

The actual Voyager desktop app shows the source replacement summary and plays the revised seven-second film, including its title and closing card.

This is a different operation from asking a model for another video. The model supplies new pixels; the editable timeline controls the cut. Voyager can perform the source replacement, render the revision and inspect the same project in one conversation. The reusable project is the advantage: the next character doesn't require reconstructing the title timing and ending.

The native timeline diff showed one changed media source. The title and end-card clips retained their positions, and the rendered audio mixes were identical.

[Download both clips, exact prompts and the editable video project](https://cdn.moda.app/voyager/blog/ai-video-character-replacement/character-recast-kit-d9ad32470ff5d70a.zip). Keep the folder together so the project can find its media. For a related way to protect exact design elements, see our [editable poster animation tutorial](/blog/layered-poster-motion).

## Change the choice you actually mean to change

Use recasting when the performance is already right and the design is still negotiable. Choose a clear reference, inspect the motion, and keep the precise parts of the deliverable in an editable timeline. You can explore another character without reopening every decision that made the first film work.


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