# Google Veo 3.1 Lite - Core.Today AI API

> Google's cost-efficient Veo 3.1 variant for high-volume video generation — text-to-video, image-to-video and first/last-frame interpolation at 720p or 1080p, 4/6/8 seconds, with natively synchronized audio on every clip.

- **Provider**: Google
- **Model ID**: google/veo-3.1-lite
- **Category**: Video Generation
- **Credits**: 930 per 8s 720p video — billed per second (720p 116/s, 1080p 186/s; audio included). 1080p requires 8s (1490)
- **Speed**: Medium
- **Quality**: High

## Features
- Native synchronized audio on every clip — dialogue, sound effects and ambience
- Text-to-video and image-to-video
- First/last-frame interpolation for smooth transitions
- 720p or 1080p, 16:9 or 9:16, 4/6/8 second clips
- Lowest per-second price in the Veo 3.1 family

## Use Cases
- High-volume social clips with sound
- Short dialogue scenes with spoken lines in quotes
- Animating product images into short ads
- Transitions between two keyframes

## 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

### Required
- **prompt**: string - Text prompt for video generation. Put dialogue in quotes and describe sound effects and ambience for richer audio

### Optional
- **image**: string - Input image to animate into a video. Ideal images are 16:9 or 9:16 and 1280x720 or 720x1280
- **last_frame**: string - Ending image for interpolation. When provided with an input image, creates a smooth transition between the two images
- **aspect_ratio**: string (default: 16:9) - Video aspect ratio
  Options: 16:9, 9:16
- **duration**: integer (default: 8) - Video duration in seconds. Must be 8 when using 1080p resolution
  Options: 4, 6, 8
- **resolution**: string (default: 720p) - Resolution of the generated video. 4k is not supported for Veo 3.1 Lite
  Options: 720p, 1080p
- **seed**: integer - Random seed. Doesn't guarantee determinism but slightly improves it

## Examples

### Dialogue Scene with Audio
An 8-second 720p clip with spoken dialogue and ambient sound — 930 credits
```json
{
  "model": "google/veo-3.1-lite",
  "input": {
    "prompt": "A close-up of two old friends reuniting at a train station. The woman gasps, 'I can't believe it's really you!' and they embrace tightly. The sound of a train whistle echoes in the background, ambient station noise, emotional orchestral music swells gently.",
    "duration": 8,
    "resolution": "720p",
    "aspect_ratio": "16:9"
  }
}
```

### Short Image-to-Video
A 4-second 720p animation of a still image — 4s at 116/s
```json
{
  "model": "google/veo-3.1-lite",
  "input": {
    "prompt": "Animate this scene with gentle camera movement and ambient sounds",
    "image": "https://example.com/your-image.jpg",
    "duration": 4,
    "resolution": "720p"
  }
}
```

## 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
- Audio is always generated and included in the price — describe the sounds you want in the prompt
- 1080p only supports 8-second clips; use 720p for 4s or 6s videos
- Use 4s clips at 720p for the cheapest iterations, then render the final at the length you need
- Veo 3.1 Lite does not support 4k, video extension or reference images — use Veo 3.1 for those

## Documentation
https://replicate.com/google/veo-3.1-lite