Edit Existing Video With AI: Which Platform for What Job

Generating video from nothing gets the headlines, but much of the useful work is changing footage that already exists: swapping a product, fixing a background, moving a shoot from summer to winter, or restyling a clip entirely. Each platform approaches this differently, and the key question is always the same: how much of the original do you need to keep? This guide compares the tools that edit video, as of November 2026.

Editing tools at a glance

Runway Aleph 2.0: the most precise

Runway launched Aleph 2.0 with a new app, Edit Studio, on 21 May 2026. It handles clips up to 30 seconds at 1080p and works in three ways:

• Localised edits change only what you ask for and keep the rest close to the original.
• Image-level control: edit one frame (in an image tool, or by hand) and Aleph applies that look to the whole clip.
• Multi-shot editing applies one change across the relevant shots of a cut sequence.

Edit Studio previews a change as an image before you spend credits on video, and is built around common jobs: swapping products or colourways, changing backgrounds, seasonal versions of a campaign, changing light or time of day, removing distractions, restyling, and fixing problems from the shoot. It is available on all paid Runway plans in the desktop web app.

Luma Modify Video: same motion, new look

Luma's Modify Video transforms uploaded footage, whether live action, animation or a phone clip, into a new style or setting while keeping its motion and camera movement. You can also change single elements such as an outfit, face or prop, or add effects like smoke or fire. Three strength levels set how far it strays: Adhere for subtle changes, Flex for bigger ones and Reimagine for a new world. Uploads are limited to 10 seconds, and the original audio is kept. Luma's Ray3 Modify, released in December 2025, added start and end frames and a character reference that maps an actor's performance onto a new character.

Kling 4.0: editing inside a generator

Kling 4.0, released in October 2026, makes targeted editing part of its main workflow. You can change expressions, body movement, characters and objects, backgrounds, camera position and movement, style, weather, and colours or materials. It accepts up to five input clips, one of them primary, with a combined length of up to 30 seconds. If you generate in Kling anyway, this saves moving footage between tools. Background on the generator itself is in our Kling image-to-video guide.

Google Flow: edit by conversation

Google's Gemini Omni models, launched at I/O in May 2026, can edit your own videos as well as generate new ones. In Flow you describe the change, such as a different environment, angle, style or detail, and refine it over several turns without losing the original scene. Omni video edits cost 40 Flow credits each, and Omni Flash is for Google AI Plus, Pro and Ultra subscribers. Flow's August 2026 update added start and end frames and export at 1080p or 4K.

Seedance 2.5: fix part of a generated clip

Seedance 2.5 can change one region or timestamp of a clip it generated, such as removing an object or changing the background, without regenerating the whole thing. CapCut calls this Intelligent Edit Mode. It is a repair tool for generated shots rather than a way to edit camera footage.

Choosing by how much you keep

• Keep everything but one thing (a product, a logo, a sky): Runway Aleph 2.0, or Kling 4.0 editing.
• Keep the motion, change the look: Luma Modify Video on Adhere or Flex, or an Aleph restyle.
• Keep the idea, explore: conversational edits in Flow, or Luma on Reimagine.
• Keep a performance, change the character: see our separate guide to copying motion from a reference video, and Luma's Ray3 Modify character reference.

Try it

Take a 5 to 10 second phone clip of an object on a table and ask each tool for the same change.

Change the season to winter: light snow falling outside the window, cooler blue daylight, frost on the glass. Keep the table, the cup and the camera movement exactly as they are.

Judge three things: did anything you didn't ask about change, did the light on the cup match the new season, and did the camera move stay identical? The tool that changes least of what you wanted kept is usually the right one for client work.

Editing produces lots of near-identical versions, and it is easy to lose track of which prompt made which. Dreamdrive, a free Chrome extension, saves each result as you make it with its prompt, model and settings, so the version the client approved is easy to find again.