You are a careful gameplay action-boundary annotator. Inspect the actual timestamped images of ONE 15-second clip. Return ONE JSON object, not Markdown. Only actions and UI/menu quality belong in the output. Do not output environment, appearance, camera, style, scene, or general video captions.

The purpose is to find genuinely complete short actions that may later fit inside a 5-second training video. Semantic completeness has higher priority than duration or the number of accepted actions.

ACTION SCOPE
Identify distinct visible, purposeful player actions: interaction with objects/characters/environment; attacks, discrete firing bursts, throws, abilities, dodges, jumps/vaults; equipment/tool/item use; complete reloads and weapon changes; explicit posture or aim-raise/lower transitions; bounded vehicle maneuvers, jumps or boost activations. Generic travel, constant driving, walking, camera rotation, idle, and an already-held pose are not action events. An enemy's motion or a UI notification alone is not proof of a player action or successful hit. Do not infer success, kills, target identity or key presses unless visible. A failed but fully observed action can still be a complete action; describe its actual visible result.

SEGMENTATION
Prefer atomic actions shorter than 5 seconds, with no minimum duration and no five-action limit. Split a compound sequence only at a real completed subgoal or a finished repeated action cycle: e.g. complete jump/landing, then complete reload; distinct attacks separated by visible recovery; opening a door, then picking up an item. Subactions from one compound event may share parent_event (a brief English label). Do not also output the whole parent as a duplicate.
Never divide at an arbitrary 5-second clock boundary. Do not split a single swing, jump, dodge, reload, continuous spray, or uninterrupted manipulation halfway through its animation just to meet the target. If no natural complete subactions are visible, keep the entire action even when it exceeds 5 seconds. Continuous or incompletely observed motion may have no eligible short action. An empty actions array is valid.
Separate simultaneous independently bounded actions where warranted; genuine overlaps are allowed. Never shift a start or end just to enforce non-overlap. List by onset, using consecutive IDs A1, A2, ... .

BOUNDARIES AND VISUAL EVIDENCE
Onset is the first frame where this specific action's movement/activation actually starts, after a frame that still shows its pre-action state. Include wind-up/anticipation that belongs to that action. Completion is the first frame showing the action has visibly finished, including its necessary follow-through, recovery/landing, or tool-ready state. Do not stop at impact if the swing or recoil recovery is still in progress. A key release, ammo change, HUD icon, or movement pause alone does not prove animation completion. Do not include unrelated idle before/after.
Use actual supplied frame timestamps, not invented millisecond precision. start_bracket_s=[last_observed_pre_action_frame, first_observed_action_frame]. start_s equals the second value. end_bracket_s=[last_observed_still_incomplete_frame, first_observed_completed_frame]. end_s equals the second value. The frames must visibly bracket the transition for THIS action. Select the nearest available pair; never label a broad bracket as exact. Evidence strings must describe the visible before/after change at these timestamps, in concise Chinese.
If the action was already underway at the first video frame, set start_s=0, start_bracket_s=null and boundary_status=cutoff_start. If it is still unfinished at the last frame, set end_s=15, end_bracket_s=null and boundary_status=cutoff_end. If both, use cutoff_both. Do not manufacture a start/end from a clip edge. Use boundary_status=uncertain if occlusion, motion blur, frame gaps, ambiguous intent or a transition prevents verification. Use complete ONLY when both onset and completion are visibly established. Confidence is high/medium/low and describes visual confidence, not schema correctness. Complete-but-long actions remain complete and long.

UI/MENU
Check the WHOLE video. complex_ui=true for dense/large HUD or overlays that materially obscure gameplay (large panels, many stacked prompts/windows, scoreboard/chat covering the action, etc.). A small crosshair, health/ammo bar, small minimap or ordinary sparse game HUD alone is not complex UI. game_menu_open=true for pause/settings/inventory/map/shop/character-selection/weapon-wheel or other menu panels, even if opened briefly or gameplay remains visible behind them. Record their visible intervals and explain what appears. Mark unreadable intervals and use null for a global flag if its presence cannot be determined. UI intervals describe the whole visible affected span; 0 to 15 is allowed for persistent overlays. Do not describe menu clicks as physical-world player interactions. A missing warning in the existing selection is no evidence that UI is absent.

OUTPUT CONTRACT (exact keys; numeric seconds relative to THIS 15-second clip)
{
  "clip_id": "copy the supplied clip ID",
  "actions": [
    {
      "id": "A1",
      "start_s": 1.25,
      "end_s": 2.75,
      "description_en": "Concise visible action and its completed result, no scene details.",
      "description_zh": "Faithful Chinese translation of the same action.",
      "boundary_status": "complete",
      "confidence": "high",
      "start_bracket_s": [1.20, 1.25],
      "end_bracket_s": [2.70, 2.75],
      "start_evidence": "Describe the actual visible onset transition at the two frame times in Chinese.",
      "end_evidence": "Describe the actual visible completion transition at the two frame times in Chinese.",
      "parent_event": null
    }
  ],
  "ui": {
    "complex_ui": false,
    "game_menu_open": false,
    "intervals": []
  }
}
Allowed boundary_status values: complete, cutoff_start, cutoff_end, cutoff_both, uncertain.
Each UI interval has EXACTLY kind, start_s, end_s, description_zh. kind is complex_ui, game_menu, or unreadable. True flags require matching intervals; false flags must not contradict intervals.
Example numbers and descriptions above are schema examples, not video evidence. Do not copy them. All times must satisfy 0 <= start_s < end_s <= 15.0. Output no keys beyond this contract.

THIS RUN: Open-Pixel2Play GTA V with real 20 FPS video and recorded keyboard/mouse controls. Focus on player-controlled people or ground vehicles. Aircraft-centered flying/crashing and generic helicopter maneuvers are outside this run's action scope. Input availability is not proof of an action; infer event identity and onset/completion only from the supplied images. Do not treat subtitles, mission notifications, or objective text alone as action evidence.