# LatentSync - Core.Today AI API

> ByteDance's open-source lipsync — re-syncs a video's mouth movements to any audio track using latent diffusion. State-of-the-art open lipsync quality for dubbing and localization.

- **Provider**: ByteDance
- **Model ID**: bytedance/latentsync
- **Category**: Video Generation
- **Credits**: 220 per run (runtime grows with video length)
- **Speed**: Slow
- **Quality**: High

## Features
- Video + audio → lip-synced video
- State-of-the-art open-source lipsync
- Latent diffusion mouth re-generation
- Guidance scale control

## Use Cases
- Video dubbing and localization
- Fixing TTS-narrated presenter videos
- Music video lip-sync
- Marketing video language swaps

## API Endpoint

Base URL: https://api.core.today/v1
Create Prediction: POST /predictions
Get Status: GET /predictions/{job_id}

## Authentication
Header: X-API-Key: YOUR_API_KEY

## Input Parameters

### Optional
- **video**: string - Input video with a visible face
- **audio**: string - Audio track to sync the lips to
- **guidance_scale**: number (default: 1) - Guidance scale for generation
- **seed**: integer (default: 0) - Random seed (0 for random)

## Examples

### Dub a Presenter Video
Sync a presenter's lips to a new Korean voiceover
```json
{
  "model": "bytedance/latentsync",
  "input": {
    "video": "https://example.com/presenter.mp4",
    "audio": "https://example.com/korean-voiceover.mp3"
  }
}
```

## Response Format
```json
{
  "job_id": "abc123",
  "status": "pending | processing | completed | failed",
  "result": "URL or data (when completed)"
}
```

## Usage Flow
1. POST /predictions with model and input -> receive job_id
2. GET /predictions/{job_id} -> poll until status is completed or failed
3. Result contains output URL(s)

## Tips
- Works best with front-facing, well-lit faces
- Pair with a TTS model (e.g. ElevenLabs) to build a full dubbing pipeline
- Longer videos take proportionally longer to process
- Only process videos of people who have consented

## Documentation
https://replicate.com/bytedance/latentsync