Tag Archives: opencv python

Recording a specific Window using OpenCV-Python

Installing Libraries:

To install PIL and pywin32, write

Installing PIL, win32gui, win32api,win32con
Python

pip install pillow pywin32

1

pip install pillow pywin32

in the cmd(See here). pywin32 will install win32gui, win32api, and win32con.
For installing winGuiAuto, download winGuiAuto.py from here. Save this as winGuiAuto.py in the python -> lib -> site-packages.

Steps:

Create the window that you want to record (I used cv2.imshow() for that)
Give the window name that you want to record in winGuiAuto.findTopWindow()
Keep the window on top and set its position using win32gui.SetWindowPos()
Get the coordinates of the window using win32gui.GetWindowPlacement()
Grab an image of the area using ImageGrab.grab()
Append all these images into a list.
Create a VideoWriter object using cv2.VideoWriter()
Convert each image color and save it.

Code:

import numpy as np
import cv2
from PIL import ImageGrab
import win32api
import winGuiAuto
import win32gui
import win32con

cap = cv2.VideoCapture(0)

# Capture the window frame by frame
image_list = []
for _ in range(70):
    ret, frame = cap.read()
    cv2.imshow('SCORE',frame)
    cv2.waitKey(1)
    hwnd = winGuiAuto.findTopWindow("SCORE")
    win32gui.SetWindowPos(hwnd, win32con.HWND_TOPMOST, 0,0,0,0,
    win32con.SWP_NOMOVE | win32con.SWP_NOSIZE)
    rect = win32gui.GetWindowPlacement(hwnd)[-1]
    image = ImageGrab.grab(rect)
    image_list.append(image)

height,width,channel = np.array(image).shape
cap.release()
cv2.destroyAllWindows()


out = cv2.VideoWriter('video.avi',cv2.VideoWriter_fourcc(*'DIVX'), 5, (width,height))
 
for images in image_list:
    out.write(cv2.cvtColor(np.array(images),cv2.COLOR_BGR2RGB))
out.release()

# Save into .gif
#import imageio
#image_gif = []
#for images in image_list:
#    print(np.array(images))
#    image_gif.append(np.array(images))
#imageio.mimsave('movie.gif', image_gif,duration=0.2)

import numpy as np

import cv2

from PIL import ImageGrab

import win32api

import winGuiAuto

import win32gui

import win32con

cap = cv2.VideoCapture(0)

# Capture the window frame by frame

image_list = []

for _ in range(70):

ret, frame = cap.read()

cv2.imshow('SCORE',frame)

cv2.waitKey(1)

hwnd = winGuiAuto.findTopWindow("SCORE")

win32gui.SetWindowPos(hwnd, win32con.HWND_TOPMOST, 0,0,0,0,

win32con.SWP_NOMOVE | win32con.SWP_NOSIZE)

rect = win32gui.GetWindowPlacement(hwnd)[-1]

image = ImageGrab.grab(rect)

image_list.append(image)

height,width,channel = np.array(image).shape

cap.release()

cv2.destroyAllWindows()

out = cv2.VideoWriter('video.avi',cv2.VideoWriter_fourcc(*'DIVX'), 5, (width,height))

for images in image_list:

out.write(cv2.cvtColor(np.array(images),cv2.COLOR_BGR2RGB))

out.release()

# Save into .gif

#import imageio

#image_gif = []

#for images in image_list:

# print(np.array(images))

# image_gif.append(np.array(images))

#imageio.mimsave('movie.gif', image_gif,duration=0.2)

If you want to make a .gif file, uncomment the last part.

Note: This works well for windows 8.1, but you might find some difficulty in capturing full window in windows 10.

Hope you enjoy reading. If you have any doubt/suggestion please feel free to ask and I will do my best to help or improve myself. Good-bye until next time.

Extracting and Saving Video Frames using OpenCV-Python

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In this tutorial, I will show you how to extract and save frames from a video file. Prerequisites are Chapter 1 and 2.

Steps:

Open the Video file or camera using cv2.VideoCapture()
Read frame by frame
Save each frame using cv2.imwrite()
Release the VideoCapture and destroy all windows

Now, Let’s code

import cv2

# Opens the Video file
cap= cv2.VideoCapture('C:/New/Videos/Play.mp4')
i=0
while(cap.isOpened()):
    ret, frame = cap.read()
    if ret == False:
        break
    cv2.imwrite('kang'+str(i)+'.jpg',frame)
    i+=1

cap.release()
cv2.destroyAllWindows()

import cv2

# Opens the Video file

cap= cv2.VideoCapture('C:/New/Videos/Play.mp4')

i=0

while(cap.isOpened()):

ret, frame = cap.read()

if ret == False:

break

cv2.imwrite('kang'+str(i)+'.jpg',frame)

i+=1

cap.release()

cv2.destroyAllWindows()

If you don’t have any video, no need to worry. Open the camera instead of the file using cv2.VideoCapture(0) and start extracting frames.

Use: We can perform a number of operations on these frames like crop, flip, reverse etc. save them into a list and iterate over them to get cropped/flipped/reversed video. (See How you can make Video from images)

Hope you enjoy reading. If you have any doubt/suggestion please feel free to ask and I will do my best to help or improve myself. Good-bye until next time

Creating Video from Images using OpenCV-Python

43 Replies

In this blog, we will do a small project using OpenCV-Python where we will be creating video from image sequences. This project is entirely based on what we read in Chapter 1 and 2. Let’s start

Steps:

Fetch all the image file names using glob
Read all the images using cv2.imread()
Store all the images into a list
Create a VideoWriter object using cv2.VideoWriter()
Save the images to video file using cv2.VideoWriter().write()
Release the VideoWriter and destroy all windows.

Let’s see the code

import cv2
import numpy as np
import glob

img_array = []
for filename in glob.glob('C:/New folder/Images/*.jpg'):
    img = cv2.imread(filename)
    height, width, layers = img.shape
    size = (width,height)
    img_array.append(img)


out = cv2.VideoWriter('project.avi',cv2.VideoWriter_fourcc(*'DIVX'), 15, size)
 
for i in range(len(img_array)):
    out.write(img_array[i])
out.release()

import cv2

import numpy as np

import glob

img_array = []

for filename in glob.glob('C:/New folder/Images/*.jpg'):

img = cv2.imread(filename)

height, width, layers = img.shape

size = (width,height)

img_array.append(img)

out = cv2.VideoWriter('project.avi',cv2.VideoWriter_fourcc(*'DIVX'), 15, size)

for i in range(len(img_array)):

out.write(img_array[i])

out.release()

glob.glob(Pathname) fetches all the filenames present in that path. ‘*.jpg’ means all the jpg files. So, in code glob.glob() fetches the filename of all the jpg files present in that path.

Hope you enjoy reading.

If you have any doubt/suggestion please feel free to ask and I will do my best to help or improve myself. Good-bye until next time.

Read, Write and Display Videos with OpenCV Python

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In this blog, we will see how to Read, Write and Display Videos using OpenCV. Since a video is made up of images, most of the commands we learned in the previous blog also applies here.

Let’s see by an example how to capture video from the camera and display it.

import numpy as np
import cv2

cap = cv2.VideoCapture(0)

while(True):
    ret, frame = cap.read()
    
    cv2.imshow('frame',frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

while(True):

ret, frame = cap.read()

cv2.imshow('frame',frame)

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

break

cap.release()

cv2.destroyAllWindows()

cv2.VideoCapture(0) will open the default camera. You can select the second camera by passing 1, third by passing 2 and so on. This creates a VideoCapture object (“cap” here).

cap.read() capture frame by frame. This returns two values, frame and ret. If the frame is read correctly, ret will be True otherwise False.

cv2.waitKey(1) & 0xFF == ord(‘q’) will exit the video when ‘q’ is pressed.

cap.release() closes video file or capturing device.

If you want to play a video from a file, just change the cv2.VideoCapture(0) function in the above code by giving the file path as cv2.VideoCapture(‘F:/downloads/Python.mp4’). Also, use the appropriate time for cv2.waitKey() function (25 will be OK).

Saving a Video:

First, create a VideoWriter object with cv2.VideoWriter(output filename, fourcc, fps, frameSize). fourcc(4-character code of codec) is used to compress the frames. After creating this object, use object.write() to save the video. Let’s see an example

import numpy as np
import cv2

cap = cv2.VideoCapture(0)
fourcc = cv2.VideoWriter_fourcc(*'XVID')
out = cv2.VideoWriter('output.avi',fourcc, 20.0, (640,480))
while(True):
    ret, frame = cap.read()
    cv2.imshow('frame',frame)
    out.write(frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

fourcc = cv2.VideoWriter_fourcc(*'XVID')

out = cv2.VideoWriter('output.avi',fourcc, 20.0, (640,480))

while(True):

ret, frame = cap.read()

cv2.imshow('frame',frame)

out.write(frame)

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

break

cap.release()

cv2.destroyAllWindows()

Now, you might have got some feeling about the basic video commands in OpenCV. Hope you enjoy reading.

If you have any doubt/suggestion please feel free to ask and I will do my best to help or improve myself. Good-bye until next time.

TheAILearner

Mastering Artificial Intelligence

Tag Archives: opencv python

Recording a specific Window using OpenCV-Python

Installing Libraries:

Steps:

Code:

Extracting and Saving Video Frames using OpenCV-Python

Steps:

Creating Video from Images using OpenCV-Python

Steps:

Read, Write and Display Videos with OpenCV Python