{
  "frames": [
    {
      "requested_t": -4.0,
      "actual_t": -4.0
    },
    {
      "requested_t": -3.5,
      "actual_t": -3.5
    },
    {
      "requested_t": -3.0,
      "actual_t": -3.0
    },
    {
      "requested_t": -2.5,
      "actual_t": -2.5
    },
    {
      "requested_t": -2.0,
      "actual_t": -2.0
    },
    {
      "requested_t": -1.5,
      "actual_t": -1.5
    },
    {
      "requested_t": -1.0,
      "actual_t": -1.0
    },
    {
      "requested_t": -0.5,
      "actual_t": -0.5
    },
    {
      "requested_t": 2.2,
      "actual_t": 2.1999999999999993
    }
  ],
  "purpose": "核对红灯出现、货车接近与人工操作之前的视觉线索",
  "video_anchor_s": 10.0,
  "note": "使用元数据锚点，不按主观场景判断移动视频；不从未标定画面测算距离或推断路权。"
}