Recording video in specified time intervals and then saving them into file OpenCv Python

问题

Here are my goals.

Capture video continuously until 'q; is pressed
Every ten seconds save the video in created directory file
Continue step two until 'q' is pressed

I am executing the following code. But when creating files it's creating 6kb files and saying cannot play. I am fairly new to opencv and python. Not sure what I am missing. Running this code on pycharm with Python 3.6. Also the

cv2.imshow('frame',frame)

stops after ten seconds but recording is happening in background and files are created.

import numpy as np
import cv2
import time
import os
import random
import sys


fps=24
width=864
height=640
video_codec=cv2.VideoWriter_fourcc('D','I','V','X')

name = random.randint(0,1000)
print (name)
if (os.path.isdir(str(name)) is False):
    name = random.randint(0,1000)
    name=str(name)

name = os.path.join(os.getcwd(), str(name))
print('ALl logs saved in dir:', name)
os.mkdir(name)


cap = cv2.VideoCapture(0)
ret=cap.set(3, 864)
ret=cap.set(4, 480)
cur_dir = os.path.dirname(os.path.abspath(sys.argv[0]))


start=time.time()
video_file_count = 1
video_file = os.path.join(name, str(video_file_count) + ".avi")
print('Capture video saved location : {}'.format(video_file))


while(cap.isOpened()):
    start_time = time.time()
    ret, frame = cap.read()
    if ret==True:
        cv2.imshow('frame',frame)
        if (time.time() - start > 10):
            start = time.time()
            video_file_count += 1
            video_file = os.path.join(name, str(video_file_count) + ".avi")
            video_writer = cv2.VideoWriter(video_file,video_codec, fps,(int(cap.get(3)),int(cap.get(4))))
            time.sleep(10)
        if cv2.waitKey(1) & 0xFF == ord('q'):
            break
    else:
        break
cap.release()
cv2.destroyAllWindows()

I want files with the recorded videos. Files are generated but size 6kb and nothing is being recorded.

回答1:

You're almost there! Given that I understood what your goal is, and with minimal change to your code, here is what worked for me.

This writes a new video file every ten seconds while recording each frame into the current video.

import numpy as np
import cv2
import time
import os
import random
import sys


fps = 24
width = 864
height = 640
video_codec = cv2.VideoWriter_fourcc("D", "I", "V", "X")

name = random.randint(0, 1000)
print(name)
if os.path.isdir(str(name)) is False:
    name = random.randint(0, 1000)
    name = str(name)

name = os.path.join(os.getcwd(), str(name))
print("ALl logs saved in dir:", name)
os.mkdir(name)


cap = cv2.VideoCapture(0)
ret = cap.set(3, 864)
ret = cap.set(4, 480)
cur_dir = os.path.dirname(os.path.abspath(sys.argv[0]))


start = time.time()
video_file_count = 1
video_file = os.path.join(name, str(video_file_count) + ".avi")
print("Capture video saved location : {}".format(video_file))

# Create a video write before entering the loop
video_writer = cv2.VideoWriter(
    video_file, video_codec, fps, (int(cap.get(3)), int(cap.get(4)))
)

while cap.isOpened():
    start_time = time.time()
    ret, frame = cap.read()
    if ret == True:
        cv2.imshow("frame", frame)
        if time.time() - start > 10:
            start = time.time()
            video_file_count += 1
            video_file = os.path.join(name, str(video_file_count) + ".avi")
            video_writer = cv2.VideoWriter(
                video_file, video_codec, fps, (int(cap.get(3)), int(cap.get(4)))
            )
            # No sleeping! We don't want to sleep, we want to write
            # time.sleep(10)

        # Write the frame to the current video writer
        video_writer.write(frame)
        if cv2.waitKey(1) & 0xFF == ord("q"):
            break
    else:
        break
cap.release()
cv2.destroyAllWindows()

来源：https://stackoverflow.com/questions/55411269/recording-video-in-specified-time-intervals-and-then-saving-them-into-file-openc

标签

python

OpenCV

video

camera

vision