OpenCV: Couldn't read video stream from file

Python
,
1

hello i’m testing opencv with video. I can normally capture image from camera but i think there is a codec issue cause when i save the stream from camera or when i try to load a video from a file it doesn’t work

i’m using mac os Catalina 10.15.7, python 3.8.5, ffmpeg 4.3.1

this is my code

import cv2
import numpy as np 
vid = cv2.VideoCapture('trailer.mp4')
while(vid.isOpened()):
    ret, frame = vid.read()
    cv2.imshow('frame',frame)

    k = cv2.waitKey(25)
    if k == 27:
        break

vid.release()
cv2.destroyAllWindows()

The error i get is OpenCV: Couldn’t read video stream from file

what’s the problem?? is it a codec error?