[经验]解决使用opencv 高分辨率下的摄像头卡顿不流畅

目录

发现

分析

解决

总结

发现

环境

ubuntu 16.04

python 2.7 (anaconda 的环境)

cv 版本 3.4

安装方式 pip install opencv-contrib-python

问题

最近在做一个项目，需要使用opencv 打开摄像头，然后录制视频，在默认的参数下，opencv打开摄像头都是非常流畅的，但是在高分辨率下，摄像头使用如下的代码的时候就非常的不流畅，而且很卡，比如如下的代码做演示就非常的卡

import time import numpy as np import cv2 resv = (1920, 1080) def show_video(): cap = cv2.VideoCapture(1) cap.set(cv2.CAP_PROP_FRAME_WIDTH, 1920) cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080) # cap.set(cv2.CAP_PROP_BUFFERSIZE,10) while (True): # Capture frame-by-frame ret, frame = cap.read() # Our operations on the frame come here # gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # Display the resulting frame # print(frame.shape) cv2.imshow('frame', frame) if cv2.waitKey(1) & 0xFF == ord('q'): break # When everything done, release the capture cap.release() cv2.destroyAllWindows()

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

import time

import numpy as np

import cv2

resv = (1920, 1080)

def show_video():

cap = cv2.VideoCapture(1)

cap.set(cv2.CAP_PROP_FRAME_WIDTH, 1920)

cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080)

# cap.set(cv2.CAP_PROP_BUFFERSIZE,10)

while (True):

# Capture frame-by-frame

ret, frame = cap.read()

# Our operations on the frame come here

# gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

# Display the resulting frame

# print(frame.shape)

cv2.imshow('frame', frame)

if cv2.waitKey(1) & 0xFF == ord('q'):

break

# When everything done, release the capture

cap.release()

cv2.destroyAllWindows()

在代码中，我设定了视频的分辨率为1080p , 这个时候演示出来的视频画面就非常的卡，是摄像头本身就不支持吗？我看了自己的设备参数 ，标明设备是支持1080p的

分析

我打开ubuntu系统的自带camera cheese 工具，不论是录制，还是拍摄，都是1080p无卡顿现象，这就说明本身不是设备的问题，这个时候我在想，是否有参数可以设置FPS，尝试在代码中加入

cap.set(cv2.CAP_PROP_FPS, 30)

1

2

cap.set(cv2.CAP_PROP_FPS, 30)

将FPS设定在30帧，依然没有效果？难道是opencv的问题，尝试使用google 搜索关键字 opencv python set fps fake 得到答案

CV_CAP_PROP_FPS is a NOT a fake. See cap_libv4l.cpp(1) in OpenCV github repo. The key is to make sure, you use libv4l over v4l while configuring OpenCV. For that, before running cmake, install libv4l-dev sudo apt-get install libv4l-dev Now while configuring OpenCV with cmake, enable option, WITH_LIBV4L. If all goes good, in configuration status, you will see some thing similar to below

1

2

3

4

5

CV_CAP_PROP_FPS is a NOT a fake. See cap_libv4l.cpp(1) in OpenCV github repo. The key is to make sure, you use libv4l over v4l while configuring OpenCV. For that, before running cmake, install libv4l-dev

sudo apt-get install libv4l-dev

Now while configuring OpenCV with cmake, enable option, WITH_LIBV4L. If all goes good, in configuration status, you will see some thing similar to below

从答案里面得知，我们需要使用libv4l库，并且，在使用opencv 编译版本的时候，要开启这个feature ，很明显 ，当前我使用的opencv应该是直装版本，没有经过编译的，那知道问题在哪，我们进行尝试

解决

安装依赖项

sudo apt-get install libv4l-dev

1

2

sudo apt-get install libv4l-dev

下载opencv 源码

https://codeload.github.com/opencv/opencv/tar.gz/3.4.2 ，本次使用的3.4.2的版本

卸载之前的opencv

pip uninstall opencv-contrib-python

1

2

pip uninstall opencv-contrib-python

编译opencv

进入opencv 目录

mkdir build cd build cmake -D WITH_LIBV4L=ON ../ make -j8 make install ldconfig cp lib/cv2.so /home/bruce/miniconda2/lib/python2.7/site-packages # 注意，这里是当前使用的python环境

1

2

3

4

5

6

7

8

9

mkdir build

cd build

cmake -D WITH_LIBV4L=ON ../

make -j8

make install

ldconfig

cp lib/cv2.so /home/bruce/miniconda2/lib/python2.7/site-packages # 注意，这里是当前使用的python环境

验证

这次使用的是录制视频并输出视频的代码

def simple_video(minutes=5): start = int(time.time()) cap = cv2.VideoCapture(1) cap.set(cv2.CAP_PROP_FRAME_WIDTH, 1920) cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080) cap.set(cv2.CAP_PROP_FPS, 25) # cap.set(cv2.CV_CAP_PROP_BUFFERSIZE, 20) # Define the codec and create VideoWriter objectXVID # fourcc = cv2.VideoWriter_fourcc(*'XVID') fourcc = cv2.VideoWriter_fourcc(*'XVID') out = cv2.VideoWriter('{}.avi'.format(str(start)), fourcc, 25.0, (1920, 1080)) while (cap.isOpened()): step = int(time.time()) ret, frame = cap.read() if ret == True: frame = cv2.flip(frame, 0) # img = cv2.resize(frame,(1920,1080)) # write the flipped frame out.write(frame) cv2.imshow('frame', frame) if (cv2.waitKey(1) & 0xFF == ord('q')) or ((step - start) >= minutes * 60): print("enter to the time used") break else: break # Release everything if job is finished cap.release() out.release() cv2.destroyAllWindows() if __name__ == '__main__': simple_video(1)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

def simple_video(minutes=5):

start = int(time.time())

cap = cv2.VideoCapture(1)

cap.set(cv2.CAP_PROP_FRAME_WIDTH, 1920)

cap.set(cv2.CAP_PROP_FRAME_HEIGHT, 1080)

cap.set(cv2.CAP_PROP_FPS, 25)

# cap.set(cv2.CV_CAP_PROP_BUFFERSIZE, 20)

# Define the codec and create VideoWriter objectXVID

# fourcc = cv2.VideoWriter_fourcc(*'XVID')

fourcc = cv2.VideoWriter_fourcc(*'XVID')

out = cv2.VideoWriter('{}.avi'.format(str(start)), fourcc, 25.0, (1920, 1080))

while (cap.isOpened()):

step = int(time.time())

ret, frame = cap.read()

if ret == True:

frame = cv2.flip(frame, 0)

# img = cv2.resize(frame,(1920,1080))

# write the flipped frame

out.write(frame)

cv2.imshow('frame', frame)

if (cv2.waitKey(1) & 0xFF == ord('q')) or ((step - start) >= minutes * 60):

print("enter to the time used")

break

else:

break

# Release everything if job is finished

cap.release()

out.release()

cv2.destroyAllWindows()

if __name__ == '__main__':

simple_video(1)

录制了1分钟的视频，看了一下结果，还不错，非常流畅，成功解决这个问题

总结

这次我们主要从，发现问题，假设问题，搜索问题的几个角度 来成功解决我们在工程上的一些问题，突破点就是验证自己的想法，使用正常的关键字去寻找问题的答案，OK，这次的分享就到这里

参考文档:

– 在ubunt下安装opencv

OpenCV 视频

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。