Kling O3 Edit Video on fal: Replacing a Person in a Clip for $0.14 per Second (October 2026)
Kling's O3 video editor changes what happens in an existing 3 to 15 second clip from a text prompt and up to four reference images. Price, limits, the @Element syntax, and why we rejected the earlier version and are testing it again.
Kling O3 is Kling's "omni" model family, and its video-to-video edit endpoint is the one that matters for anyone who wants to change a person in footage that already exists. You hand it a clip, a prompt and up to four reference images, and it returns the clip with the edit applied. It lists on fal at $0.14 per second on both the Pro and Standard tiers, with a 4K version at $0.42. fal itself describes it as its preferred secondary option for editing existing footage, behind MiniMax's models. We rejected an earlier version of this editor in April; this is why we are looking at it again.
What it accepts
| Input | Limit |
|---|---|
| Source video length | 3 to 15 seconds |
| Source resolution | 720 to 3,840 pixels |
| File size | up to 200 MB |
| Frame rate | 23 to 60 fps |
| References | elements and image_urls together, at most 4 |
| Prompt | up to 2,500 characters |
| Audio | keep_audio is on by default |
An element is a character you define with a frontal image plus one to three further angles. In the prompt you refer to the source clip as @Video1 and to the character as @Element1, for example "Replace the man in @Video1 with @Element1, keep the camera and the background". That explicit reference is the feature that makes it a candidate for replacing a person, rather than only restyling a scene. The safety checker is mandatory, so content the filter dislikes is rejected rather than quietly altered.
The "Omni" upgrade that added these inputs and the 4K version was reported in mid-June 2026 by a single source we could find, so take the date loosely; the limits above come from fal's schema.
What it costs
| Clip length | Pro or Standard ($0.14) | 4K ($0.42) |
|---|---|---|
| 5 seconds | $0.70 | $2.10 |
| 10 seconds | $1.40 | $4.20 |
| 15 seconds (the maximum) | $2.10 | $6.30 |
That is half what HappyHorse video-edit costs per delivered second at 720p ($0.28, because it bills the input seconds as well as the output seconds), and a little under half of Recast's reported rates. Cheap only matters if the result is usable.
Why we rejected it and why we are testing it again
On 19 April 2026 we tested the O3 edit endpoint on a real Reel and retired it: outfit, hair and skin drifted at every scene boundary, which makes a multi-scene replacement look like three different people. That verdict predates the June upgrade, and fal's later positioning of the endpoint is the reason it is back on our list. Our plan is a five-second clip, one element, the same source we use for the other candidates, at about $0.70. Until that runs, we make no claim that it holds a face.
Two things to know about drift on any editor like this. It grows with the length of the clip and with motion, so a 15-second edit is a harder test than a 5-second one. And it concentrates at cuts: a model that sees the clip in one piece but has to re-imagine the person after each cut is gambling with identity every time the shot changes.
When to use it directly
- You have a single continuous shot of 3 to 15 seconds with one person in it.
- You can supply a frontal photo and one or two other angles of the replacement.
- You are happy to run a five-second test first.
For a Reel with many cuts or several people, compare it with Recast, which keeps cuts natively and maps photos to people, and with HappyHorse video-edit, which is what our autopilot runs. Our walk-through of replacing a person in a video puts the three side by side.
Limits worth knowing
It edits; it does not originate. If the movement itself is what you want to copy onto a new character, Motion Control is built for that. And because it is a Kling endpoint, Kling's policy on public figures applies: a rejection is a decision, not a bug. Use your own face.
Common questions
What does @Element1 mean?
In the prompt, @Video1 refers to your source clip and @Element1 to a character you defined from a frontal image plus one to three other angles. The prompt tells the model what to change and what to keep.
Why did you reject it before?
In April it drifted in outfit, hair and skin at scene boundaries on a real Reel. That was before the later upgrade, which is why we are retesting.
How long can the source be?
Between 3 and 15 seconds, up to 200 MB, at 23 to 60 frames per second.
Can I turn off the safety checker?
No. It is mandatory on this endpoint, so a request the filter dislikes is rejected.
How to do this without code: Replacing a person in a clip is the autopilot, and Kling O3 edit is a candidate we are retesting for it. In AutoHustle this is the autopilot: paste the Reel link, add one photo of yourself and confirm the plan (about 4 credits per second of finished video, so 60 credits for a full 15-second call; analysing the Reel is free). See How to put your face in any Reel and Recreate an Instagram Reel.
Related reading: Kling O3 Reference-to-Video on fal: Put a Character From Photos Into a New Scene (October 2026) · Kling 3.0 vs HappyHorse 1.1 for Character Replacement (August 2026)
For developers: the fal endpoints
| Model | fal endpoint |
|---|---|
| Kling O3 Pro video-to-video edit | fal-ai/kling-video/o3/pro/video-to-video/edit |
| Kling O3 Standard video-to-video edit | fal-ai/kling-video/o3/standard/video-to-video/edit |
| Kling O3 4K video-to-video edit | fal-ai/kling-video/o3/4k/video-to-video/edit |
Prices read on 18 October 2026: $0.14 per second (Pro and Standard), $0.42 per second (4K). Prompt references: @Video1, @Element1. keep_audio defaults to true; enable_safety_checker cannot be turned off.