Converting minimal demo to Pub/Sub only transmits single frame.

[mullenba]

When I convert the basic demo from the repo's main page to Pub/Sub, the receiving computer shows the first frame, then doesn't change. The demo as written works fine.

I've tested that the loops are running, but the frame image doesn't change.

Sender:

import socket
import time
from imutils.video import VideoStream
from imagezmq import imagezmq

sender = imagezmq.ImageSender(connect_to='tcp://*:5555', REQ_REP=False)

rpi_name = socket.gethostname() # send RPi hostname with each image
picam = VideoStream(usePiCamera=True).start()
time.sleep(2.0)  # allow camera sensor to warm up

while True:  # send images as stream until Ctrl-C
   frame = picam.read()
   sender.send_image(rpi_name, frame)

Receiver:

import cv2
from imagezmq import imagezmq

image_hub = imagezmq.ImageHub(open_port='tcp://192.168.68.134:5555', REQ_REP=False)

while True:  # show streamed images until Ctrl-C
    rpi_name, image = image_hub.recv_image()
    cv2.imshow(rpi_name, image) # 1 window for each RPi
    cv2.waitKey(1)

[jeffbass]

I don't see any issues with your code, but I would suggest you run the PUB / SUB example programs from the examples folder. Docs and links to code are here.

Please try that and let me know what happens. I know that this pair of example programs works. Of course, you'll need to change your TCP address in the receiver appropriately.

[mullenba]

The test_4 example works.

[mullenba]

Doing more experimenting, it appears to be on the receive side. If I start the sender, then start the receiver with nothing in front of the camera, I see the frame of the empty space. If I then close the receiver and put my hand in front of the camera, restarting shows my hand.

If I let it run for a long time and occasionally move my hand in front of the camera, it does seem to be changing, one frame every few seconds on about a minute delay.

I'm working with a Raspberry Pi and Windows desktop, and happens in both Windows and Ubuntu WSL.

[mullenba]

Looks to be an issue with imutils VideoStream. Replacing it with a direct call to picamera and sending that works fine.

[jeffbass]

Thanks for the update. I have heard other reports of imageZMQ users resorting to direct calls to picamera after having issues with imutils VideoStream. For example see this issue an imagenode / imageZMQ user had with imutils VideoStream: imagenode issue 15.