camera.py

import cv2
import threading
import time

class Camera:
    def __init__(self, device_index=0, width=640, height=480, fps=30):
        self.device_index = device_index
        self.cap = cv2.VideoCapture(self.device_index, cv2.CAP_ANY)
        # Try to set format (not all cams will accept)
        self.cap.set(cv2.CAP_PROP_FRAME_WIDTH, width)
        self.cap.set(cv2.CAP_PROP_FRAME_HEIGHT, height)
        self.cap.set(cv2.CAP_PROP_FPS, fps)

        if not self.cap.isOpened():
            raise RuntimeError(f"Could not open video device {device_index}")

        self.lock = threading.Lock()
        self.frame = None
        self.running = True
        self.thread = threading.Thread(target=self._reader, daemon=True)
        self.thread.start()

    def _reader(self):
        # Always read the latest frame; drop old frames to reduce latency.
        while self.running:
            ret, frame = self.cap.read()
            if not ret:
                time.sleep(0.01)
                continue
            # JPEG encode for MJPEG streaming
            ok, buf = cv2.imencode(".jpg", frame, [int(cv2.IMWRITE_JPEG_QUALITY), 80])
            if not ok:
                continue
            with self.lock:
                self.frame = buf.tobytes()

    def get_jpeg(self):
        with self.lock:
            return self.frame

    def close(self):
        self.running = False
        if self.thread.is_alive():
            self.thread.join(timeout=1.0)
        self.cap.release()