Record before and after with Webcam

Question

Hi I'm making a securitycam. I made it so green outlines marke the object. now it should start a video after a object is found. (I want it to start recording after a movement was detected for 60 seconds.) Then make this into a file I can see. How can I do that?

Here is my code:

import cv2

vc = cv2.VideoCapture(0)

if vc.isOpened(): # try to get the first frame
    rval, frame = vc.read()
else:
    rval = False


# capturing video
capture = vc

while capture.isOpened():
    # to read frame by frame
    _, img_1 = capture.read()
    _, img_2 = capture.read()

    # find difference between two frames
    diff = cv2.absdiff(img_1, img_2)

    # to convert the frame to grayscale
    diff_gray = cv2.cvtColor(diff, cv2.COLOR_BGR2GRAY)

    # apply some blur to smoothen the frame
    diff_blur = cv2.GaussianBlur(diff_gray, (5, 5), 0)

    # to get the binary image
    _, thresh_bin = cv2.threshold(diff_blur, 20, 255, cv2.THRESH_BINARY)

    # to find contours
    contours, hierarchy = cv2.findContours(thresh_bin, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)

    # to draw the bounding box when the motion is detected
    for contour in contours:
        x, y, w, h = cv2.boundingRect(contour)
        if cv2.contourArea(contour) > 300:
            cv2.rectangle(img_1, (x, y), (x+w, y+h), (0, 255, 0), 2)
            print("Somethin was moved")

    else:
        print("Nothing was moved")
    # cv2.drawContours(img_1, contours, -1, (0, 255, 0), 2)

    # display the output
    cv2.imshow("Output", img_1)
    if cv2.waitKey(100) == 13:
        exit()