Fix camera capture reliability and rewrite tracking for available mediapipe/hardware

source/Tbd/helper.py

@@ -2,6 +2,7 @@ import numpy as np
 import json
 import cv2
 import threading
+import time
 
 from dataclasses import dataclass, field, asdict
 from typing import List, Optional, Tuple, Dict
@@ -122,7 +123,39 @@ class CameraObject():
         #self.capture = cv2.VideoCapture(self.index, cv2.CAP_DSHOW)
         self.capture.set(cv2.CAP_PROP_FRAME_WIDTH, 2048.0)
         self.capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 1536.0)
- 
+
+    def open(self, width: int = 1920, height: int = 1080, max_attempts: int = 5) -> bool:
+        """
+        Open this camera on demand via MSMF. Only MSMF has been able to open all
+        6 cameras on this rig at all (DSHOW hits a hard concurrent-instance limit
+        around 2-3 devices on this hardware) - the tradeoff is MSMF cameras should
+        not be kept open simultaneously in large numbers, so callers are expected
+        to open() right before use and close() right after.
+        """
+        if self.capture is not None:
+            return True
+
+        for attempt in range(1, max_attempts + 1):
+            capture = cv2.VideoCapture(self.index, cv2.CAP_MSMF)
+            if capture.isOpened():
+                capture.set(cv2.CAP_PROP_FRAME_WIDTH, width)
+                capture.set(cv2.CAP_PROP_FRAME_HEIGHT, height)
+                capture.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'MJPG'))
+                self.capture = capture
+                self.pxWidth = width
+                self.pxHeight = height
+                return True
+
+            capture.release()
+            time.sleep(0.3 * attempt)
+
+        return False
+
+    def close(self):
+        if self.capture is not None:
+            self.capture.release()
+            self.capture = None
+
 
 @dataclass
 class Hand2D():