▼OpenCV-Python操作UBS摄像头“pipeline”

1. import numpy as np
   import cv2 as cv
   cap = cv.VideoCapture(0)
   if not cap.isOpened():
       print("Cannot open camera")
       exit()
   cap.set(cv.CAP_PROP_FRAME_HEIGHT,240)
   cap.set(cv.CAP_PROP_FRAME_WIDTH,320)
   '''使用cv.VideoCapture.set设置摄像头分辨率是出现错误'''
   while True:
       # Capture frame-by-frame
       ret, frame = cap.read()
       # if frame is read correctly ret is True
       if not ret:
           print("Can't receive frame (stream end?). Exiting ...")
           break
       # Our operations on the frame come here
       gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
       # Display the resulting frame
       cv.imshow('frame', gray)
       if cv.waitKey(1) == ord('q'):
           break
   # When everything done, release the capture
   cap.release()
   cv.destroyAllWindows()
   

   问题：

在执行的时候出现：

[ WARN:0] global /root/opencv/modules/videoio/src/cap_gstreamer.cpp (933) open OpenCV | GStreamer warning: Cannot query video position: status=0, value=-1, duration=-1
[ WARN:0] global /root/opencv/modules/videoio/src/cap_gstreamer.cpp (1757) handleMessage OpenCV | GStreamer warning: Embedded video playback halted; module v4l2src0 reported: Internal data flow error.
[ WARN:0] global /root/opencv/modules/videoio/src/cap_gstreamer.cpp (515) startPipeline OpenCV | GStreamer warning: unable to start pipeline
[ WARN:0] global /root/opencv/modules/videoio/src/cap_gstreamer.cpp (1055) setProperty OpenCV | GStreamer warning: no pipeline
Can't receive frame (stream end?). Exiting ...
[ WARN:0] global /root/opencv/modules/videoio/src/cap_gstreamer.cpp (480) isPipelinePlaying OpenCV | GStreamer warning: GStreamer: pipeline have not been created

 

解决方式：原因是摄像头不支持set的分辨率，查看摄像头的相关说明，修改设置的分辨率为允许设置的分辨率