In this video lesson I show you how to understand the data structures returned by MediaPipe. I show you how to peel the data structure back, to get at the useful information.

When you run face detection with MediaPipe, the results object it returns is not a normal dictionary or list. It is a special custom object called SolutionOutputs. The easiest way to explore it is to start by checking the main attribute: results.detections. This is a Python list that contains one entry for every face detected in the current frame. If no faces are found, results.detections will be None or an empty list.

To extract useful information, you loop through results.detections. Each item in that list is a Detection object. From this object, you can access two main things: the confidence score using detection.score[0], and the location data using detection.location_data. Inside location_data, you will find relative_bounding_box (which gives you xmin, ymin, width, and height as values between 0 and 1) and relative_keypoints (a list of 6 facial points such as eyes, nose, and mouth).

The standard method is to first get the frame’s height and width, then multiply the normalized values (like xmin and width) by the actual pixel dimensions of the image to convert them into usable pixel coordinates. You can then use these coordinates with OpenCV functions such as cv2.rectangle() for the box or cv2.circle() for the keypoints.

By using simple print(type()), print(dir()), and print() statements on results, results.detections, and individual detection objects, you can quickly discover the full structure. This step-by-step approach — starting from results → detections → individual detection → location_data — lets you reliably reach all the useful information MediaPipe provides.

Below is the code we developed in the video.