initial refactoring

frigate/video.py

@@ -0,0 +1,41 @@
+import time
+import datetime
+import cv2
+from . util import tonumpyarray
+
+# fetch the frames as fast a possible, only decoding the frames when the
+# detection_process has consumed the current frame
+def fetch_frames(shared_arr, shared_frame_time, frame_lock, frame_ready, frame_shape, rtsp_url):
+    # convert shared memory array into numpy and shape into image array
+    arr = tonumpyarray(shared_arr).reshape(frame_shape)
+
+    # start the video capture
+    video = cv2.VideoCapture()
+    video.open(rtsp_url)
+    # keep the buffer small so we minimize old data
+    video.set(cv2.CAP_PROP_BUFFERSIZE,1)
+
+    while True:
+        # check if the video stream is still open, and reopen if needed
+        if not video.isOpened():
+            success = video.open(rtsp_url)
+            if not success:
+                time.sleep(1)
+                continue
+        # grab the frame, but dont decode it yet
+        ret = video.grab()
+        # snapshot the time the frame was grabbed
+        frame_time = datetime.datetime.now()
+        if ret:
+            # go ahead and decode the current frame
+            ret, frame = video.retrieve()
+            if ret:
+                # Lock access and update frame
+                with frame_lock:
+                    arr[:] = frame
+                    shared_frame_time.value = frame_time.timestamp()
+                # Notify with the condition that a new frame is ready
+                with frame_ready:
+                    frame_ready.notify_all()
+    
+    video.release()