如何在python中使用opencv同时播放多个视频？

Question

Hi guys I am stuck at this point. I want to play four videos on my screen using opencv . Can anyone help me how to do that? Suppose I want to play simultaneously

1. first.avi
2. second.avi
3. third.avi
4. fourth.avi

I am referring following code. It plays very well for single avi file. Is it necessary to concatenate or i can run in four different windows?. any suggestions are welcome import cv2 import numpy as np

# Create a VideoCapture object and read from input file
# If the input is the camera, pass 0 instead of the video file name
cap = cv2.VideoCapture('first.avi')
cap2 =cv2.VideoCapture('second.avi')

if (cap.isOpened()== False): 
  print("Error opening video stream or file")
if (cap2.isOpened()== False): 
  print("Error opening video stream or file")

while(cap.isOpened()||cap2.isOpened()):
  # Capture frame-by-frame
  ret, frame = cap.read()
  ret, frame1 = cap2.read()
  if ret == True:

   # Display the resulting frame
    cv2.imshow('Frame',frame)
    cv2.imshow('Frame', frame1)


   # Press Q on keyboard to  exit
   if cv2.waitKey(25) & 0xFF == ord('q'):
  break
  else: 
    break


cap.release()
cap2.release()

cv2.destroyAllWindows()

Answer 1

For playing multiple videos, we have to use unique window titles for each video. Here is a sample code demonstrating how it can be achieved.

import numpy as np
import cv2

names = ['first.avi', 'second.avi', 'third.avi', 'fourth.avi'];
window_titles = ['first', 'second', 'third', 'fourth']


cap = [cv2.VideoCapture(i) for i in names]

frames = [None] * len(names);
gray = [None] * len(names);
ret = [None] * len(names);

while True:

    for i,c in enumerate(cap):
        if c is not None:
            ret[i], frames[i] = c.read();


    for i,f in enumerate(frames):
        if ret[i] is True:
            gray[i] = cv2.cvtColor(f, cv2.COLOR_BGR2GRAY)
            cv2.imshow(window_titles[i], gray[i]);

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


for c in cap:
    if c is not None:
        c.release();

cv2.destroyAllWindows()

PS: This code is just a quick and dirty example for demo purpose only. Tested with python 2 and OpenCV 3.2 on Ubuntu 14.04.