Beginners • OpenCV on a http webrtc stream streamed from a raspberry pi using mediated

Code:

cam1:runnInit: bash -c 'rpicam-vid -t 0 --camera 0 -nopreview —-codec yuv420 -width 1280 -height 720 -inline -listen -0 - | - ffmpeg -f rawvideo -pix_fmt yuv420p -s:v -i /dev/stdin -c:v libx264-preset ultrafast -tune zerolatency -f rtsp rtsp://localhost: $RTSP_PORT/$MTX_PATH'runOnInitRestart: yes

Code:

import mathimport cv2from ultralytics import YOLOimport ultralytics.utils.plotting as plotting#import motioncontrolimport numpy as npfrom collections import defaultdict# Load a pretrained YOLOv11n modelmodel = YOLO("yolo11n.pt")source = 'http://{ipaddress}:8889/cam1'cap = cv2.VideoCapture(source)#colors= plotting.colors()track_history = defaultdict(lambda: [])distance=[]while cap.isOpened():    success, frame = cap.read()    if success:        results = model.track(frame, persist=True)        for result in results:            xyxy = result.boxes.xyxy.cpu().numpy()            xywh=result.boxes.xywh.cpu().numpy()            for box in xywh:                if xywh.size >0:                    raw_centre_x = (box[0]).astype(int)                    #centre_x = raw_centre_x.astype(int)                    raw_centre_y = (box[1]).astype(int)                    #centre_y = raw_centre_y.astype(int)                     # Draw circles at the center coordinates                    cv2.circle(frame, (raw_centre_x,raw_centre_y), 5, color=(255, 255, 255), thickness=2)                #try to use normalized coordinate values that way you can very simply use the sign to tell wether the object is to the right or to the left.                # Centre of frame is 640 width and 360 height        cv2.circle(frame, (640,360), 5, color=(255, 27, 108), thickness=2)        annotated_frame = results[0].plot()                cv2.imshow("YOLO11 Tracking", annotated_frame)        if cv2.waitKey(1) & 0xFF == ord("q"):            break    else:        breakcap.release()cv2.destroyAllWindows()