fix(fam-edge): 事件时间戳改相对时间定位 - prompt 要求输出视频内相对时间 HH:MM:SS（模型对相对位置判断更准），后端按 开始时间+偏移 精确计算绝对时间落库；事件截图直接用偏移跳帧，消除模型绝对时间推算误差导致的图文不符

fam-edge/src/fam_edge/video_processor.py

@@ -40,6 +40,29 @@ def _parse_event_start_from_filename(filename: str) -> str:
     return ''
 
 
+def _parse_event_ts(ts: str, start_dt):
+    """解析事件时间戳 -> (绝对时间显示串, 视频内偏移秒)。
+
+    优先识别"视频内相对时间" HH:MM:SS（新 prompt 要求，定位最准）；
+    兼容旧数据的绝对时间 YYYY-MM-DD HH:MM:SS（偏移=绝对-视频开始）。
+    """
+    ts = (ts or '').strip()
+    m = re.match(r'^(\d{1,2}):(\d{2}):(\d{2})$', ts)
+    if m:
+        off = int(m.group(1)) * 3600 + int(m.group(2)) * 60 + int(m.group(3))
+        if start_dt is not None:
+            abs_ts = (start_dt + timedelta(seconds=off)).strftime('%Y-%m-%d %H:%M:%S')
+            return abs_ts, float(off)
+        return ts, float(off)
+    if start_dt is not None:
+        try:
+            ev_dt = datetime.strptime(ts[:19], '%Y-%m-%d %H:%M:%S')
+            return ts, (ev_dt - start_dt).total_seconds()
+        except ValueError:
+            pass
+    return ts, 0.0
+
+
 class VideoProcessor:
     def __init__(self, db: oracle_db.OracleDB):
         self.config = load_config()
@@ -129,22 +152,32 @@ class VideoProcessor:
         summary = result.get('global_summary', '')
         provider = result.get('compute_provider', 'unknown')
 
-        # 归一化 events 时间戳（若模型给的是相对偏移，这里不强制；以模型输出为准）
+        # 视频开始时间（绝对时间由后端精确计算：开始时间 + 相对偏移）
+        start_dt = None
+        vrow = self.db.get_video_by_id(video_id)
+        if vrow and vrow['event_start_time']:
+            try:
+                start_dt = datetime.strptime(vrow['event_start_time'], '%Y-%m-%d %H:%M:%S')
+            except ValueError:
+                pass
+
         norm_events = []
+        offsets = []
         for ev in events:
+            abs_ts, off = _parse_event_ts(ev.get('timestamp'), start_dt)
             norm_events.append({
-                "timestamp": str(ev.get('timestamp', '')),
+                "timestamp": abs_ts,
                 "description": str(ev.get('description', '')),
                 "people": [str(p) for p in ev.get('people', []) if p],
                 "is_attention_event": bool(ev.get('is_attention_event', False)),
             })
+            offsets.append(off)
 
         event_ids = self.db.mark_video_processed(video_id, summary, norm_events, people, provider)
-        # 缩略图 + 每个事件对应时间点的画面截图（供前端展示；失败不影响主流程）
-        row = self.db.get_video_by_id(video_id)
-        if row and row['local_path']:
-            self._generate_thumb(video_id, row['local_path'])
-            self._generate_event_thumbs(video_id, row['local_path'], norm_events, event_ids)
+        # 缩略图 + 每个事件对应时间点的画面截图（用相对偏移直接定位，避免模型绝对时间误差）
+        if vrow and vrow['local_path']:
+            self._generate_thumb(video_id, vrow['local_path'])
+            self._generate_event_thumbs(video_id, vrow['local_path'], offsets, event_ids)
 
         # 更新 people 表（标签级，待 person_service 合并）
         for p in people:
@@ -184,50 +217,34 @@ class VideoProcessor:
             return False
 
     def _generate_event_thumbs(self, video_id: int, video_path: str,
-                               events: List[dict], event_ids: List[int]):
-        """按事件时间戳定位视频帧，生成事件画面截图 ev_{event_id}.jpg"""
+                               offsets: List[float], event_ids: List[int]):
+        """按事件在视频内的偏移秒定位帧，生成事件画面截图 ev_{event_id}.jpg"""
         try:
             import cv2
-            from datetime import datetime as _dt
         except Exception as e:
             logger.warning(f"事件截图依赖缺失 video_id={video_id}: {e}")
             return
         try:
-            start_str = self.db.get_video_by_id(video_id)['event_start_time'] or ''
-            start_dt = None
-            if start_str:
-                try:
-                    start_dt = _dt.strptime(start_str, '%Y-%m-%d %H:%M:%S')
-                except ValueError:
-                    pass
             thumbs = self._thumbs_dir()
             cap = cv2.VideoCapture(video_path)
             try:
-                for ev, eid in zip(events, event_ids):
-                    offset = 0.0
-                    ts = str(ev.get('timestamp', ''))
-                    if start_dt and ts:
-                        try:
-                            ev_dt = _dt.strptime(ts[:19], '%Y-%m-%d %H:%M:%S')
-                            offset = (ev_dt - start_dt).total_seconds()
-                        except ValueError:
-                            pass
-                    if offset < 0:
-                        offset = 0.0
-                    cap.set(cv2.CAP_PROP_POS_MSEC, int(offset * 1000))
+                for off, eid in zip(offsets, event_ids):
+                    if off < 0:
+                        off = 0.0
+                    cap.set(cv2.CAP_PROP_POS_MSEC, int(off * 1000))
                     ok, frame = cap.read()
                     if not ok or frame is None:
                         cap.set(cv2.CAP_PROP_POS_FRAMES, 0)
                         ok, frame = cap.read()
                     if not ok or frame is None:
-                        logger.warning(f"事件截图失败 ev_{eid}: 无法读取 offset={offset:.0f}s")
+                        logger.warning(f"事件截图失败 ev_{eid}: 无法读取 offset={off:.0f}s")
                         continue
                     h, w = frame.shape[:2]
                     if w > 640:
                         frame = cv2.resize(frame, (640, int(h * 640 / w)))
                     out = os.path.join(thumbs, f"ev_{eid}.jpg")
                     cv2.imwrite(out, frame, [cv2.IMWRITE_JPEG_QUALITY, 65])
-                    logger.info(f"事件截图已生成 ev_{eid}.jpg (offset={offset:.0f}s)")
+                    logger.info(f"事件截图已生成 ev_{eid}.jpg (offset={off:.0f}s)")
             finally:
                 cap.release()
         except Exception as e: