python读取mp4视频

import cv2# 读取视频文件
video_path = 'path_to_your_video.mp4'  # 将此处替换为你的MP4文件路径
cap = cv2.VideoCapture(video_path)# 检查视频是否成功打开
if not cap.isOpened():print("Error: Could not open video.")exit()# 播放视频
while True:ret, frame = cap.read()if not ret:break# 显示视频帧cv2.imshow('Video', frame)# 按 'q' 键退出播放if cv2.waitKey(1) & 0xFF == ord('q'):break# 释放视频捕获对象并关闭所有显示窗口
cap.release()
cv2.destroyAllWindows()

python读取摄像头

import cv2def capture_video(camera_index=0):"""Capture video from the specified camera index (default is 0 for the built-in camera).Press 'q' to exit the video stream."""# 打开摄像头cap = cv2.VideoCapture(camera_index)if not cap.isOpened():print(f"Cannot open camera {camera_index}")returnwhile True:# 读取帧ret, frame = cap.read()if not ret:print("Cannot receive frame (stream end?). Exiting ...")break# 显示帧cv2.imshow('Camera', frame)# 按下 'q' 键退出if cv2.waitKey(1) == ord('q'):break# 释放摄像头并关闭所有窗口cap.release()cv2.destroyAllWindows()if __name__ == "__main__":capture_video(camera_index=0)  # 0 表示默认的笔记本自带摄像头

检查有几个可用摄像头

import cv2def list_cameras(max_cameras=10):"""List available cameras."""available_cameras = []for index in range(max_cameras):cap = cv2.VideoCapture(index)if cap.isOpened():available_cameras.append(index)cap.release()return available_camerasdef select_camera(camera_index):"""Open the specified camera and start capturing video."""cap = cv2.VideoCapture(camera_index)if not cap.isOpened():print(f"Cannot open camera {camera_index}")returnwhile True:ret, frame = cap.read()if not ret:print("Cannot receive frame (stream end?). Exiting ...")breakcv2.imshow(f'Camera {camera_index}', frame)if cv2.waitKey(1) == ord('q'):breakcap.release()cv2.destroyAllWindows()if __name__ == "__main__":cameras = list_cameras()print(f"Available cameras: {cameras}")if cameras:selected_camera = cameras[0]  # You can change the index to select a different cameraprint(f"Using camera {selected_camera}")select_camera(selected_camera)else:print("No cameras found.")