{
  "requested_second": 85,
  "exact_baseline_frame": {
    "id": "f2550",
    "source_frame_index": 2550,
    "timestamp_seconds": 85.0,
    "source_pts_seconds": 85.0,
    "timestamp": "85.000000",
    "reasons": [
      "baseline_1fps"
    ],
    "image": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002550.webp",
    "width": 405,
    "height": 720,
    "selection_reasons": [
      "baseline_1fps_or_last"
    ],
    "source_width": 720,
    "source_height": 1280,
    "image_url": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002550.webp"
  },
  "nearby_frames": [
    {
      "id": "f2520",
      "source_frame_index": 2520,
      "timestamp_seconds": 84.0,
      "source_pts_seconds": 84.0,
      "timestamp": "84.000000",
      "reasons": [
        "baseline_1fps"
      ],
      "image": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002520.webp",
      "width": 405,
      "height": 720,
      "selection_reasons": [
        "baseline_1fps_or_last"
      ],
      "source_width": 720,
      "source_height": 1280,
      "image_url": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002520.webp"
    },
    {
      "id": "f2550",
      "source_frame_index": 2550,
      "timestamp_seconds": 85.0,
      "source_pts_seconds": 85.0,
      "timestamp": "85.000000",
      "reasons": [
        "baseline_1fps"
      ],
      "image": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002550.webp",
      "width": 405,
      "height": 720,
      "selection_reasons": [
        "baseline_1fps_or_last"
      ],
      "source_width": 720,
      "source_height": 1280,
      "image_url": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002550.webp"
    },
    {
      "id": "f2580",
      "source_frame_index": 2580,
      "timestamp_seconds": 86.0,
      "source_pts_seconds": 86.0,
      "timestamp": "86.000000",
      "reasons": [
        "baseline_1fps"
      ],
      "image": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002580.webp",
      "width": 405,
      "height": 720,
      "selection_reasons": [
        "baseline_1fps_or_last"
      ],
      "source_width": 720,
      "source_height": 1280,
      "image_url": "https://ai-video-relay-check-20261027.pages.dev/frames/frame-00002580.webp"
    }
  ],
  "screen_observation": {
    "time": 85.0,
    "source_frame_index": 2550,
    "raw_ocr": "",
    "raw_caption": "",
    "raw_title": "",
    "screen_caption": "",
    "screen_title": "",
    "reviewed_changes": [],
    "verification": "automatic OCR; not independently verified",
    "timing": "observed frame time; onset/offset not known to subsecond precision",
    "is_confirmed_speech": false
  },
  "raw_ASR_at_estimated_time": [],
  "content_section": {
    "index": 4,
    "start": 81.433333,
    "end": 93.366667,
    "title": "黑T恤盖头演示",
    "visual_observation": "人物换为黑色T恤；后段把黑衣向上拉到头面部，眼周留出开口，白色背心露出。",
    "camera": "人物主要在固定机位前抬手、拉衣，末段动作较快。",
    "uncertainty": "不推断人物身份或把衣服英文当讲话。",
    "provenance": "assistant visual review of source-frame sheets; not an independent human or automatic semantic-model benchmark"
  },
  "unknowns": [
    "ASR not a verified listening transcript",
    "Caption display time can differ from speech time",
    "Assistant observation must be cross-checked by actually opening image"
  ]
}