Next guide shows steps to write Gstreamer Plugin in Python for any Computer Vision, Image Processing task and use it in standard Gstreamer pipeline from command line. Additionally this post explains how to get/set own properties from implemented Gstreamer plugin.
Gstreamer with Python is highly flexible for data visualization. Any video streaming pipeline could be extended with custom Python plugins that allows you to draw any information (bounding boxes, confidences, class names, etc.). Next information is simple comparison of two most popular approaches to draw on gstreamer buffer: PyCairo, OpenCV.