How to fix opencv python cv2.VideoCapture rtsp onvif “nonmatching transport in server reply” error?

Question

I\'m on windows using python 3.6.4, installed opencv (3.4) through pip. Here\'s the code I\'m using:

import numpy as np
import cv2

cap = cv2.VideoCapture(\'rtsp         


        

Answer 1

I've just encountered this problem and after digging it looks like OPENCV 3.1+ defaults to TCP for the RTSP transport (my ESCAM QF600 only supports RTSP over UDP). You can prevent this from happening via setting the environment variable OPENCV_FFMPEG_CAPTURE_OPTIONS to something (e.g. dummy).

For completeness; see https://ffmpeg.org/ffmpeg-protocols.html for all options that can be set. Keys and values are separated with ';' and pairs are separated via '|'.

The offending code begins at line 809 in cap_ffmpeg_impl.hpp (https://github.com/opencv/opencv/blob/master/modules/videoio/src/cap_ffmpeg_impl.hpp)

Props to the following posts for sending me in the right direction:

ffmpeg rtsp error: Nonmatching transport in server reply

Cant get RTSP stream - nonmatching