# Skill: Video Generation with OpenAI Sora 2

Generate trailer clips, gameplay-style footage, and cinematic sequences using OpenAI's Sora 2 API. This skill covers the API workflow, prompting patterns, and cost management for game development use.

## Overview

Sora 2 generates 5-20 second video clips from text prompts or still images. For game studios, it's useful for:

- Trailer pre-visualisation (storyboard frames as video)
- Marketing clips before the game is playable
- Concept videos to test art direction
- Social media content

## Prerequisites

- OpenAI API key with Sora access
- Set `OPENAI_API_KEY` environment variable

## API Reference

### Create a video

```bash
curl -X POST "https://api.openai.com/v1/videos/generations" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sora-2",
    "prompt": "Your prompt here",
    "size": "1920x1080",
    "duration": 10,
    "n": 1
  }'
```

Response includes a generation ID. Video generation takes 2-10 minutes.

### Check status

```bash
curl "https://api.openai.com/v1/videos/generations/{generation_id}" \
  -H "Authorization: Bearer $OPENAI_API_KEY"
```

Poll until `status` is `"completed"`. The response includes a download URL.

### Download

```bash
curl -o output.mp4 "{video_download_url}"
```

### Image-to-video

Animate a still image:

```bash
curl -X POST "https://api.openai.com/v1/videos/generations" \
  -H "Authorization: Bearer $OPENAI_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "sora-2",
    "prompt": "Camera slowly pulls back, revealing the full village. Waves lap at the shore.",
    "image": "{base64_or_url_of_image}",
    "size": "1920x1080",
    "duration": 5
  }'
```

This is powerful for animating your generated concept art or key art frames.

## Models

| Model | Quality | Speed | Cost |
|-------|---------|-------|------|
| `sora-2` | High | 2-5 min | ~$0.10-0.20/clip |
| `sora-2-pro` | Highest | 5-10 min | ~$0.50-1.00/clip |

Use `sora-2` for iteration and pre-vis. Use `sora-2-pro` for final trailer clips only.

## Prompting for Game Trailers

### Structure

```
[Camera movement] + [Subject action] + [Environment] + [Lighting/mood] + [Style]
```

### Example: Opening shot

```
Slow aerial drone shot descending toward a cluster of thatched-roof huts
on a tropical island shoreline. Crystal clear turquoise water, white sand
beach, palm trees swaying gently. Golden hour sunlight, long shadows.
Stylised 3D game engine quality, warm colour palette. No text overlays.
```

### Example: Character reveal

```
Medium shot of a young Polynesian woman standing on a cliff edge, looking
out over an ocean dotted with volcanic islands. Wind blowing her hair.
She turns to face the camera with a calm, determined expression. Sunset
light behind her. Stylised 3D render, game cinematic quality.
```

### Example: Action sequence

```
Wide shot of three outrigger canoes racing across open ocean toward a
volcanic island. Waves crashing, spray in the air. Warriors paddling
in unison. Storm clouds building on the horizon. Dynamic camera
tracking the lead canoe. Stylised game engine quality.
```

## Cultural Guardrails

If your game draws from real cultures, set explicit rules:

- **No anachronistic elements** (modern objects, wrong architectural styles)
- **Research your references** --- use authentic building styles, clothing, tools
- **Avoid stereotypes** --- specific cultural elements, not generic "exotic"
- **No sacred symbols used decoratively** without understanding their meaning

## Workflow for Trailer Storyboards

1. **Write the storyboard** --- list each shot with description, duration, and camera movement
2. **Generate key frames** using image generation (see [Image Generation skill](image-generation.md))
3. **Animate key frames** using Sora 2's image-to-video
4. **Generate original clips** for shots that don't need a specific starting frame
5. **Review and iterate** --- regenerate clips that don't match the vision
6. **Compile** in a video editor (DaVinci Resolve, Premiere, etc.)

## Cost Management

| Scenario | Estimated Cost |
|----------|---------------|
| 1 test clip (sora-2, 5s) | ~$0.10 |
| 10-clip exploration session | ~$1.00 |
| 20-clip trailer storyboard | ~$2-4 |
| Final 5-clip trailer (sora-2-pro) | ~$2.50-5.00 |

**Tips:**
- Use `sora-2` (not pro) for all iteration
- Keep clips to 5-10 seconds --- shorter clips have better coherence
- Generate 2-3 variants per shot and pick the best
- Only use `sora-2-pro` for the final selected shots

## Common Mistakes

| Mistake | Fix |
|---------|-----|
| Overly long prompts | Keep under 200 words. Focus on what's visible. |
| Requesting specific text/UI | Sora can't render readable text. Add text in post. |
| Not specifying art style | Always end with style direction ("stylised 3D", "game engine quality") |
| Using sora-2-pro for iteration | Expensive and slow. Use sora-2 until you're happy with the prompt. |
| Ignoring cultural accuracy | Set guardrails before generating. Review outputs for stereotypes. |
| Not tracking costs | Log every generation with model, duration, and cost. |

## Related Skills

- [Image Generation](image-generation.md) --- create key frames to animate with Sora
- [Concept Art Pipeline](concept-art-pipeline.md) --- character and asset design workflow