1 publicasync Task<string> StartRecordingAsync(string cameraId = "")
 2  {
 3      await _sessionSemaphore.WaitAsync();
 4      try
 5      {
 6          lock (_sessionLock)
 7          {
 8              if (_currentSession != null && _currentSession.IsRecording)
 9              {
10                  return JsonConvert.SerializeObject(new { code = "400", message = "已有录制会话进行中，请先调用 Stop/StopEnd" });
11              }
12              if (!IsCameraConnected)
13              {
14                  return JsonConvert.SerializeObject(new { code = "400", message = "相机未连接，无法开始录制" });
15              }
16              var config = ConfigManager.CurrentConfig;
17              string rtspUrl = config.Rtsp1Url;
18              _currentSession = new SessionRecorder(rtspUrl);
19              if (!_currentSession.Start(outstring error))
20              {
21                  return JsonConvert.SerializeObject(new { code = "500", message = error });
22              }
23              CurrentState = RecorderState.Recording;
24              OnStatusChanged("录制会话已开始");
25              return JsonConvert.SerializeObject(new { code = "200", message = "录制会话已启动" });
26          }
27      }
28      finally
29      {
30          _sessionSemaphore.Release();
31      }
32  }

publicasync Task<string> StopRecordingAsync(string trackingNo, string watermark)
 {
     lock (_sessionLock)
     {
         if (_currentSession == null || !_currentSession.IsRecording)
         {
             return JsonConvert.SerializeObject(new { code = "400", message = "没有活跃的录制会话" });
         }
         _currentSession.AddStopPoint(trackingNo, watermark, DateTime.Now);
         return JsonConvert.SerializeObject(new { code = "200", message = "停止点已记录" });
     }
 }

publicasync Task<string> StopEndAsync(string wave)
  {
      await _sessionSemaphore.WaitAsync();
      try
      {
          SessionRecorder session = null;
          lock (_sessionLock)
          {
              if (_currentSession == null || !_currentSession.IsRecording)
                  return JsonConvert.SerializeObject(new { code = "400", message = "没有活跃的录制会话" });
              session = _currentSession;
              _currentSession = null;
          }
          string result = await session.StopEnd(wave);
          CurrentState = RecorderState.Idle;
          OnStatusChanged($"录制会话已结束，波次：{wave ?? "超时"}");
          // 快速返回，无需额外延迟
          return JsonConvert.SerializeObject(new { code = "200", message = result });
      }
      finally
      {
          _sessionSemaphore.Release();
      }
  }