README.md

input_opencv filter plugin: cvfilter_py

This plugin allows you to use a Python 3.x script to process images received by mjpg-streamer. This has been tested with Python 3.4.

To run a Python 3.x script, you can do the following:

mjpg_streamer -i "input_opencv.so --filter cvfilter_py.so --fargs path/to/filter.py"

Filter script

Your script MUST define a function called 'init_filter', that takes zero arguments and returns a single callable. This returned callable must take a single argument (a numpy array), and returns a single object (a numpy array). A simple example follows:

def filter_fn(img):
    '''
        :param img: A numpy array representing the input image
        :returns: A numpy array to send to the mjpg-streamer output plugin
    '''
    return img

def init_filter():
    return filter_fn

For a more complex example, see the included example_filter.py

Known Issues

When mjpg-streamer is terminated, a KeyError is raised in the threading module. While annoying, it's harmless. Most likely it happens because the python interpreter is destroyed on the wrong thread.

TODO

After going through all of this effort to create the code for this module, I bet it can be done a lot simpler via cython.

Authors

Dustin Spicuzza (dustin@virtualroadside.com)