Video Streaming from IP Camera in Python Using OpenCV cv2.VideoCapture

Question

I am trying to get video stream in python from IP camera but i am getting an error. I am Using Pycharm IDE.

import cv2
scheme = '192.168.100.23'


host = scheme
cap = cv2.VideoCapture('http://admin:Ebmacs8485867@'+host+':81/web/admin.html')

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

    # Place options to overlay on the video here.
    # I'll go over that later.

    cv2.imshow('Camera', frame)

    k = cv2.waitKey(0) & 0xFF
    if k == 27:  # esc key ends process
        cap.release()
        break
cv2.destroyAllWindows()

Error:
"E:\Digital Image Processing\python\ReadingAndDisplayingImages\venv\Scripts\python.exe" "E:/Digital Image Processing/python/ReadingAndDisplayingImages/ReadandDisplay.py"
Traceback (most recent call last):
  File "E:/Digital Image Processing/python/ReadingAndDisplayingImages/ReadandDisplay.py", line 14, in <module>
    cv2.imshow('Camera', frame)
cv2.error: OpenCV(4.0.1) C:\projects\opencv-python\opencv\modules\highgui\src\window.cpp:352: error: (-215:Assertion failed) size.width>0 && size.height>0 in function 'cv::imshow'

warning: Error opening file (/build/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp:901)
warning: http://admin:Ebmacs8485867@192.168.100.23:81/web/admin.html (/build/opencv/modules/videoio/src/cap_ffmpeg_impl.hpp:902)

You try to check the frame is empty or not, probably the is empty. — Bahramdun Adil, Apr 24 '19 at 11:02
That link is a webpage (html) you need the rtsp link... and this depends on the model of the camera. Also you should check `if cap.isOpened()` before the loop and `if ret` after the `ret, frame = cap.read()` line — api55, Apr 24 '19 at 11:09
can you post the rtsp link you are using? rtsp requires also another port (probably 554) — api55, Apr 24 '19 at 11:13
if i open image in new tab by click on the video stream.. the code captures the image but not capturing the frames for video. — Moazam Shahid, Apr 24 '19 at 11:13
that is NOT a rtsp link, in some cameras is something like `rtsp://192.168.100.23:554/11` ... This link changes from model to model. You are passing a html web page to connect to. This is NOT a stream but a web page. Sometimes this webpage connects to the stream via javascript or flash or something else. — api55, Apr 24 '19 at 11:18
i wrote the line cap.isOpened() before while loop with if statement ... and it prints not opened when i run the code — Moazam Shahid, Apr 24 '19 at 11:20

nathancy · Answer 1 · 2022-05-06T03:34:25.173

You're most likely getting that error due to an invalid stream link. Insert your stream link into VLC player to confirm it is working. Here's a IP camera video streaming widget using OpenCV and cv2.VideoCapture.read(). This implementation uses threading for obtaining frames in a different thread since read() is a blocking operation. By putting this operation into a separate that that just focuses on obtaining frames, it improves performance by I/O latency reduction. I used my own IP camera RTSP stream link. Change stream_link to your own IP camera link.

Depending on your IP camera, your RTSP stream link will vary, here's an example of mine:

rtsp://username:password@192.168.1.49:554/cam/realmonitor?channel=1&subtype=0
rtsp://username:password@192.168.1.45/axis-media/media.amp

Code

from threading import Thread
import cv2

class VideoStreamWidget(object):
    def __init__(self, src=0):
        # Create a VideoCapture object
        self.capture = cv2.VideoCapture(src)

        # Start the thread to read frames from the video stream
        self.thread = Thread(target=self.update, args=())
        self.thread.daemon = True
        self.thread.start()

    def update(self):
        # Read the next frame from the stream in a different thread
        while True:
            if self.capture.isOpened():
                (self.status, self.frame) = self.capture.read()

    def show_frame(self):
        # Display frames in main program
        if self.status:
            self.frame = self.maintain_aspect_ratio_resize(self.frame, width=600)
            cv2.imshow('IP Camera Video Streaming', self.frame)

        # Press Q on keyboard to stop recording
        key = cv2.waitKey(1)
        if key == ord('q'):
            self.capture.release()
            cv2.destroyAllWindows()
            exit(1)

    # Resizes a image and maintains aspect ratio
    def maintain_aspect_ratio_resize(self, image, width=None, height=None, inter=cv2.INTER_AREA):
        # Grab the image size and initialize dimensions
        dim = None
        (h, w) = image.shape[:2]

        # Return original image if no need to resize
        if width is None and height is None:
            return image

        # We are resizing height if width is none
        if width is None:
            # Calculate the ratio of the height and construct the dimensions
            r = height / float(h)
            dim = (int(w * r), height)
        # We are resizing width if height is none
        else:
            # Calculate the ratio of the 0idth and construct the dimensions
            r = width / float(w)
            dim = (width, int(h * r))

        # Return the resized image
        return cv2.resize(image, dim, interpolation=inter)

if __name__ == '__main__':
    stream_link = 'your stream link!'
    video_stream_widget = VideoStreamWidget(stream_link)
    while True:
        try:
            video_stream_widget.show_frame()
        except AttributeError:
            pass

Related camera/IP/RTSP, FPS, video, threading, and multiprocessing posts

This is good stuff. Thanks. Care to comment on the `self.thread.daemon = True`? Thanks. — user1965074, Jul 06 '20 at 19:01
@user1965074 if you dont set `daemon` to `True`, it will be a zombie process when your main program dies. We set daemon `True` so that when our parent process dies, this will also kill all child processes. See [daemon process boyzzzzzz](https://docs.python.org/3/library/threading.html#thread-objects) — nathancy, Oct 23 '20 at 21:37
I created a get_frame function that returned either self.frame or np.empty if the first frame wasn't set and that gives me a set of frames to display or process outside the class. I was amazed at how little delay there is through this compared to VLC Player where objects appear several seconds after they have left the camera. — brianlmerritt, May 25 '21 at 06:17
Does self.frame need locking so that capture operation and show operation do not collide? — Kenji Noguchi, Jun 19 '21 at 18:06
@KenjiNoguchi I found this [answer](https://stackoverflow.com/a/50668843/3067197) to your question. — BaKeR, Jul 08 '22 at 19:14

Video Streaming from IP Camera in Python Using OpenCV cv2.VideoCapture

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