error: (-5:Bad argument) CAP_IMAGES: can‘t find starting number (in the name of file): rtsp://admin_error: (-5:bad argument) cap_images: can't find st

想看一下opencv读取rtsp码流并存图的时间消耗，代码如下：

import time
import cv2

cap = cv2.VideoCapture(" rtsp://admin:xxxx2021@116.xxx.90.xxx:554/h264/ch1/main/av_stream")
ret,frame = cap.read()
for i in range(10):
    start_time = time.time()
    cv2.imwrite("./img/temp.jpeg", frame)
    end_time = time.time()
    print("process time is :", end_time - start_time)
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结果发现报错：
OpenCV(4.5.5) D:\a\opencv-python\opencv-python\opencv\modules\videoio\src\cap_images.cpp:253: error: (-5:Bad argument) CAP_IMAGES: can’t find starting number (in the name of file): rtsp://admin:xxxx2021@116.xxx.90.xxx:554/h264/
之前经常用，并没有出现过，查了一些解决方案，没效果，最后发现问题在

cap = cv2.VideoCapture(" rtsp://admin:xxxx2021@116.xxx.90.xxx:554/h264/ch1/main/av_stream")
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双引号中的rtsp地址前不能有空格，如下

cap = cv2.VideoCapture("rtsp://admin:xxxx2021@116.xxx.90.xxx:554/h264/ch1/main/av_stream")
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问题解决。
附带bmp,jpg和png格式存图的时间消耗做参考

save jpg time is : 0.04970407485961914
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save png time is : 0.11170268058776855
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save bmp time is : 0.00502777099609375
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