{
  "frames": [
    {
      "requested_t": -2,
      "actual_t": -2.0
    },
    {
      "requested_t": -1.5,
      "actual_t": -1.5
    },
    {
      "requested_t": -1,
      "actual_t": -1.0
    },
    {
      "requested_t": -0.5,
      "actual_t": -0.5
    },
    {
      "requested_t": 0,
      "actual_t": 0.0
    },
    {
      "requested_t": 0.5,
      "actual_t": 0.5
    },
    {
      "requested_t": 1,
      "actual_t": 1.0
    },
    {
      "requested_t": 1.5,
      "actual_t": 1.5
    },
    {
      "requested_t": 2,
      "actual_t": 2.0
    },
    {
      "requested_t": 3,
      "actual_t": 3.0
    },
    {
      "requested_t": 4,
      "actual_t": 4.0
    },
    {
      "requested_t": 5,
      "actual_t": 5.0
    }
  ],
  "purpose": "0017核对出弯前车制动与后续路口车辆；0021核对起步阶段横向车流与前车停止。",
  "note": "时间使用既有视频锚点；不从未标定画面测算距离或推断路权。"
}