Runway视频生成请求体

{
    "model": "runway/gen4_turbo",
    "prompt_image": "http://example.com",
    "image": "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAUA...",
    "images": [
        {
            "uri": "https://example.com/image.jpg",
            "position": "first"
        }
    ],
    "video_uri": "https://example.com/input.mp4",
    "prompt_text": "让场景充满生机，添加微风和光影效果",
    "prompt": "让场景充满生机，添加微风和光影效果",
    "ratio": "1280:720",
    "duration": 10,
    "seed": 42,
    "references": [
        {
            "type": "image",
            "uri": "https://example.com/reference.jpg"
        }
    ],
    "contentModeration": {
        "publicFigureThreshold": "auto"
    },
    "callback_url": "https://your-api.com/callback",
    "external_task_id": "my_task_123"
}