imagezmq | A set of Python classes that transport OpenCV images from one computer to another using PyZMQ messag

The answers provided by @Christoph Rackwitz are correct. The design of ImageZMQ is to send and receive OpenCV images WITHOUT any base64 encoding. The ImageSender class sends OpenCV images. The ImageHub class receives OpenCV images. Optionally, ImageZMQ can send a jpg buffer (as your Raspberry Pi client code is doing).

Your Raspberry Pi client code is based on the ImageZMQ "send jpg" example.

Your server code should therefore use the matching ImageZMQ "receive jpg" example.

The essence of the ImageZMQ "receive jpg" example code is:

Here’s a couple of things to try to get the native-zmq parts working:

Use .connect()-method for SUB-sockets : socket.connect("tcp://localhost:6666")

And .bind()-method for your PUB-sockets : socket.bind("tcp://*:6666")

It’s explained here in the guide that connect should be used to create an outgoing connection from a socket.

In the sibling doc for .bind(), it explains that it’s for accepting connections.

Also try setting socket options : socket.setsockopt(zmq.SUBSCRIBE, "")

It is described here in the guide that the SUB-sockets initially filter out all messages, so that’d explain why you’re not receiving anything. The example above provides an empty filter, which accepts all incoming messages.

It’s important to note that with PUB and SUB based distribution, that the SUB might not necessarily receive messages due to timing of its connection or network conditions. E.g. everything sent from the publisher before the subscriber connects isn’t receivable