How to record rtsp stream in opencv in better quality?

Question

Python

ok, I displayed the stream in a window and wrote it in some capacity in output.avi.

import cv2
cap = cv2.VideoCapture("rtsp://192.168.11.35")
cv2.namedWindow('main', cv2.WINDOW_NORMAL)
fourcc = cv2.VideoWriter_fourcc(*'DIVX')
out = cv2.VideoWriter('output.avi', fourcc, 12,(int(cap.get(3)),int(cap.get(4))))

while(1):
    ret, frame = cap.read()
    if ret==True:
        cv2.imshow('main', frame)
        out.write(frame)

    ch = cv2.waitKey(5)
    if ch == 27:
        break

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

how to just write a stream in a minimally modified state?
ffmpeg can write as many fps as it has, can copy the codec.
here is how to do it?