Video Processing Pipeline

[ Capture ] → [ Pre-process ] → [ Analyze ] → [ Post-process ] → [ Output ]
  webcam       resize/cvtColor    model/CV     draw/annotate    display/save
  RTSP                                                            stream

import cv2, time

cap = cv2.VideoCapture("street.mp4")
W   = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
H   = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
fps = cap.get(cv2.CAP_PROP_FPS)
writer = cv2.VideoWriter("out.mp4",
            cv2.VideoWriter_fourcc(*"mp4v"), fps, (W, H))

while True:
    ok, frame = cap.read()
    if not ok: break

    # 1. pre
    small = cv2.resize(frame, (640, 360))
    gray  = cv2.cvtColor(small, cv2.COLOR_BGR2GRAY)

    # 2. analyze
    edges = cv2.Canny(gray, 80, 180)

    # 3. post
    edges_bgr = cv2.cvtColor(edges, cv2.COLOR_GRAY2BGR)
    out = cv2.addWeighted(small, 0.7, edges_bgr, 0.3, 0)
    out = cv2.resize(out, (W, H))

    # 4. output
    writer.write(out)
    cv2.imshow("pipeline", out)
    if cv2.waitKey(1) == 27: break

cap.release(); writer.release(); cv2.destroyAllWindows()

print("FPS:    ", cap.get(cv2.CAP_PROP_FPS))
print("Frames: ", cap.get(cv2.CAP_PROP_FRAME_COUNT))
print("Width:  ", cap.get(cv2.CAP_PROP_FRAME_WIDTH))
print("Height: ", cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

# Specific frame-এ jump
cap.set(cv2.CAP_PROP_POS_FRAMES, 300)