How to save video using thread

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I am making a program that takes a video for 10 seconds when an object is detected.
If 'out' is created before 'while', the video is saved only once
when use this code .avi file is just created and there is nothing saved
Is it the right way to use threads? Or is there any other way?

import cv2
import numpy as np
import time
import threading

def thread():
    global recording,out
    recording = True
    print("recording start")
    time.sleep(10)
    recording = False
    out.release()
    print("recording end")

global recording, out

cap = cv2.VideoCapture("rtsp://128.1.1.6/profile2/media.smp")

fgbg = cv2.createBackgroundSubtractorMOG2(varThreshold=200, detectShadows=0)

fps = 60
width = int(cap.get(3))
height = int(cap.get(4))
fcc = cv2.VideoWriter_fourcc(*'XVID') 
recording = False

while(1):
    ret, frame = cap.read()
    hms = time.strftime('%H:%M:%S', time.localtime())
    hmss = time.strftime('%H_%M_%S', time.localtime())

    fgmask = fgbg.apply(frame)

    nlabels, labels, stats, centroids = cv2.connectedComponentsWithStats(fgmask)
    cv2.putText(frame,str(hms),(0,15),cv2.FONT_HERSHEY_SIMPLEX,0.5,(0,255,255))

    for index, centroid in enumerate(centroids):

        if stats[index][0] == 0 and stats[index][1] == 0:
            continue
        if np.any(np.isnan(centroid)):
            continue

        x, y, width, height, area = stats[index]
        centerX, centerY = int(centroid[0]), int(centroid[1])

        if area > 50: #Minimum size detected
            cv2.circle(frame, (centerX, centerY), 1, (0, 255, 0), 2) 
            cv2.rectangle(frame, (x, y), (x + width, y + height), (0, 0, 255)) 
            cv2.putText(frame, str(area), (centerX, y), cv2.FONT_HERSHEY_SIMPLEX, 0.5, (0, 255, 255)) # detected size

        if area > 1000 and not recording:
            t1 = threading.Thread(target=thread)
            path = 'E:\\test_' + str(hmss) + '.avi'
            out = cv2.VideoWriter(path, fcc, fps, (width, height))
            recording = True
            print(str(hms))
            t1.start()

    cv2.imshow('mask', fgmask)
    cv2.imshow('frame', frame)

    if recording:
        out.write(frame)

    k = cv2.waitKey(1) & 0xff 

cap.release()
out.release()
cv2.destroyAllWindows()