{
  "model": "doubao-seedance-2-0-260128",
  "content": [
    {
      "type": "text",
      "text": "保持主体外观与数量不变，镜头缓慢推进，轻微自然光变化，不增加物体，不切换场景。"
    },
    {
      "type": "image_url",
      "image_url": { "url": "https://YOUR-PUBLIC-IMAGE-HOST/input.png" },
      "role": "first_frame"
    }
  ],
  "ratio": "1:1",
  "duration": 4,
  "resolution": "720p",
  "generate_audio": false
}