视频讲解
OpenCV读取摄像头窗口变大且很卡的解决方法
测试过程
读取摄像头窗口变大且很卡的代码
import cv2
cap = cv2.VideoCapture(0)
if not cap.isOpened():print("Cannot open camera")exit()
while True:ret, frame = cap.read()if not ret:print("no stream!")breakcv2.imshow('frame', frame)if cv2.waitKey(1) == ord('q'):break
cap.release()
cv2.destroyAllWindows()
运行后，读取摄像头的窗口很大，而且很卡，出现如下的提示
python3 test-camera.py
[ WARN:0@0.986] global /home/jetson/Downloads/opencv-4.5.5/modules/videoio/src/cap_gstreamer.cpp (1405) open OpenCV | GStreamer warning: Cannot query video position: status=0, value=-1, duration=-1
Gtk-Message: 21:12:47.677: Failed to load module "canberra-gtk-module"
安装libcanberra-gtk-module
sudo apt-get install libcanberra-gtk-module
继续运行，还是很卡，WARN还在，修改代码如下，增加cv2.CAP_V4L2
v4l2（video for linux two）是Linux中内核提供给应用层访问音视频驱动的统一接口。v4l2中获取摄像头的能力的是通过ioctl函数的VIDIOC_QUERYCAP命令获取。
import cv2
cap = cv2.VideoCapture(0, cv2.CAP_V4L2)
if not cap.isOpened():print("Cannot open camera")exit()
while True:ret, frame = cap.read()if not ret:print("no stream!")breakcv2.imshow('frame', frame)if cv2.waitKey(1) == ord('q'):break
cap.release()
cv2.destroyAllWindows()
