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

问题

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://192.168.15.116:554/onvif1')

while(cap.isOpened()):
    ret, frame = cap.read()

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

I'm getting the following error:

[rtsp @ 03858a40] Nonmatching transport in server reply
warning: Error opening file (/build/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp:808)
warning: rtsp://192.168.15.116:554/onvif1 (/build/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp:809)

I can go to cmd and type "ffplay rtsp://192.168.15.116/onvif1" and the video will run as well as in VLC using the same rtsp address. Using cv2.VideoCapture(0) also works with my webcam.

Tried copying the file opencv_ffmpeg340.dll into all path folders, but still to no avail. Also checked build and all video I/O show up with YES, except gstreamer. I'm out of ideas.

回答1:

I installed OPENCV onto Windows 10 using Microsoft's VCPKG. After which, OPENCV worked fine - except it would not open videos files.

Without success, I tried many suggestions. Finally, what worked for me was very SIMPLE. I included opencv's BIN folder as a PATH in Windows Environment System Variables. That's it. Now, video files are opened and played just fine.

回答2:

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

来源：https://stackoverflow.com/questions/48630885/how-to-fix-opencv-python-cv2-videocapture-rtsp-onvif-nonmatching-transport-in-s

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python