Edit any part of a video with AI lip sync
A step-by-step guide to changing what someone says in a video with AI lip sync: prep the clip, clone or pick a voice, generate the line, and re-sync the lips in sync. labs.
AI lip sync lets you change what someone says in a video you have the rights to, without a reshoot. You pick a clip, write a new line, generate the voice, and a model re-renders the mouth to match the new audio. What used to take hours of frame-by-frame keyframing is now a render bar.
sync. labs does the hard part. Upload your footage, give it the new audio, and sync-3 re-syncs the speaker’s lips to match while keeping the face, lighting, and performance intact. It works on any video, whether live-action, animation, or AI-generated, usually in under three minutes.
AI lip sync re-renders the mouth to match new audio
AI lip sync takes your video and a new audio track and regenerates the speaker’s mouth so it matches the new words. The rest of the frame stays as shot. That is what makes it usable for real edits: fixing a flubbed line, localizing a message, or producing a variant, all without recutting the footage. Use clips you own or have permission to edit, and be transparent when an edit could mislead someone, the same consent-first line covered in is AI dubbing safe.
How to edit part of a video with AI lip sync, step by step
The loop is short and needs no specialized software.
- Prep your clip. Start from footage you own or have rights to, and trim it tight. A shorter clip renders faster.
- Get the new voice. Write the line you want, then generate the audio. You can clone a voice from a few minutes of clean samples in ElevenLabs, or skip cloning and use a prebuilt voice directly in sync. labs. If a clone sounds stiff, lowering the stability setting usually reads more naturally, which is one of the fixes in why AI dubbing sounds robotic.
- Generate the line. Keep scripts short. Short lines land better and render faster.
- Re-sync the lips. Upload the trimmed video and the new audio to sync. labs, pick sync-3, and generate. It takes a minute or two depending on length.
Then review it once at full speed to confirm the mouth matches, trim a frame if the timing drifts slightly, and export or share the link.
What each tool does in the workflow
| Step | Tool | What it does |
|---|---|---|
| Voice | ElevenLabs or sync. labs | Clones a voice or generates a new line from text |
| Lip sync | sync. labs (sync-3) | Re-times the mouth to match the new audio |
| Review | sync. labs playground | Preview, trim, and export or share the result |
Why creators use AI lip sync
A few practical reasons it has become a default tool:
- Repurpose old content. A clip you already have plus a new line is something nobody has seen before.
- Make custom messages. A person delivering your pitch is more memorable than a slide.
- Save time. What used to be hours of frame-by-frame edits is now a render bar.
Creators use it for reactions, tutorials, and promos, businesses use it for localization and personalized variants without reshoots, and podcasters use it to turn audio into something watchable. If you are new to the concept, what is AI lip sync covers the fundamentals, and how to turn an image into a talking video shows the version that starts from a single photo.
Frequently asked questions
Can you really change what someone says in a video?
Yes. AI lip sync regenerates the mouth to match new audio, so a video can show a speaker saying a new line. Use footage you own or have rights to, and disclose edits that could mislead a viewer.
Do you need special software to edit a video with AI lip sync?
No. You need a clip, a new audio track, and a lip sync tool. sync. labs runs in the browser: you upload the video and audio, pick sync-3, and it re-syncs the lips in a couple of minutes.
How do you get the new voice?
You can clone a voice from a few minutes of clean audio in ElevenLabs, or use a prebuilt voice directly in sync. labs. If a cloned voice sounds robotic, lowering the stability setting usually produces a more natural read.
Is there a free way to do this?
sync. labs includes 3 free videos a month at full HD with no credit card, which is enough to try the full workflow end to end before committing to a paid plan.
Will the edit look obvious?
sync-3 keeps the original face, lighting, and performance and only re-times the mouth, so a clean clip and well-matched audio read as natural. Timing drift is the usual tell, and trimming a frame fixes most of it.
Try sync-3 in the browser, upload a clip you have rights to, and change the line in a couple of minutes.