Sync-3 Lipsync - 4K Lip Sync for Any Video
Last updated: April 22, 2026
Sync-3 is a professional-grade AI lipsync model that synchronizes mouth movements in any video to match a new audio track. Developed by Sync Labs, it delivers 4K native output, full-shot processing, and built-in obstruction detection - making it the premier choice for production-quality results on real people, game characters, and animated figures.
Overview
Sync-3 replaces or synchronizes the lip movements in an existing video with a new audio track. Instead of re-filming scenes or investing in costly dubbing sessions, you simply provide a video and an audio file, and Sync-3 handles the rest.
Why choose Sync-3?
Silent Lip Animation: Unlike older models, Sync-3 can animate characters that were not speaking in the original clip by "opening" silent lips to match audio.
Full-Shot Support: Processes the entire frame rather than requiring close-cropped face shots.
Obstruction Detection: Automatically manages hands, microphones, or objects that partially cover the mouth.
Common Use Cases:
Localization: Translating content into new languages with dubbed audio.
Correction: Fixing filming errors where the wrong take was used.
Game Development: Creating NPC narration from static or idle character animations.
How to Use It
Step 1: Prepare Your Video
Visibility: Use shots where the face is clearly visible; front-facing angles produce the sharpest results.
Lighting: Ensure the mouth area is well-lit and avoid rapid camera pans or cuts.
Style: Works with humans, stylized characters, and 3D avatars.
Note: Sync-3 is designed for speech, not singing. Musical content will result in generic rather than phoneme-accurate movements.
Step 2: Prepare Your Audio
Quality: Use clean audio with minimal background noise or music.
Pacing: A natural speaking pace is ideal.
TTS Tip: If using AI-generated audio (e.g., ElevenLabs), use punctuation like exclamation marks and capital letters in your script to trigger more expressive lip movements.
Step 3: Choose a Sync Mode
The syncMode parameter determines how the model handles duration mismatches between your video and audio.
Mode | Behavior | Best For... |
cut_off (Default) | Trims the audio to match the video length. | Fixed video length where the audio end is non-critical. |
loop | Repeats the video from the start to fill the audio. | Short ambient clips or looping background characters. |
bounce | Plays video forward then reverse (back-and-forth). | Idle animations or walking cycles. |
silence | Adds silence to the audio to match a longer video. | When you want the subject to stop speaking partway through. |
remap | Adjusts video playback speed to match audio exactly. | When both full video and audio content must be preserved. |
Step 4: Run the Model
Connect your assets, select your mode, and run. Sync-3 delivers native 4K output without the need for manual cropping.
Tips for Best Results
Duration Match: Try to match video and audio lengths before processing; the closer they are, the more natural the result.
The 20% Rule: For mismatches, use remap. A video sped up or slowed down by 10% to 20% is rarely noticeable but keeps the sync coherent.
Camera Angle: Eye-level, front-facing shots provide better articulation than profile or upward-angle shots.
Known Limitations
Singing: Not optimized for musical content; movements will be generic.
Extreme Angles: Near 90-degree side views or profile shots significantly reduce tracking accuracy.
Length: Generation time increases with duration. For videos over 60 seconds, consider splitting the content into segments and concatenating them post-generation.