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• Extracting frames every second of all videos in folder

  20 octobre 2023, par Sparkiepandas

  I am trying to extract a frame every second of a video, while having multiple videos in a folder. I got it working for 1 video like this, but I think I am messing up my loop for all videos. Below is the code for 1 video that works.

  



  import cv2
pathOut = r"C:/Users/Me/Out/"
vidcap = cv2.VideoCapture(r'C:\Me\Desktop\test.mp4');
count = 0
success = True
while success:
    success,image = vidcap.read()
    print('read a new frame:',success)
    if count%30 == 0 :
         cv2.imwrite(pathOut + 'frame%d.jpg'%count,image)
    count+=1


  



  With the loop for all videos I made it up like this.

  



  import os
import cv2
pathOut = r"C:/Users/Me/Out/"
count = 0
success = True
counter = 1
listing = os.listdir(r'C:/Users/Me/videos/train')
for vid in listing:
    vid = r"C:/Users/Me/videos/train/"+vid
    cap = cv2.VideoCapture(vid)
    count = 0
    counter += 1
    while success:
        success,image = cap.read()
        print('read a new frame:',success)
        if count%30 == 0 :
             cv2.imwrite(pathOut + 'frame%d.jpg'%count,image)
        count+=1


  



  My vid loop does not seems to work because it is only taking one video. Then it states false, probably because there are no frames left, but I do not know how to push it forward to the next video. I think I need to do some minor adjustment, does anybody have any idea what exactly ?

  


• FFMPEG : Creating a video, which has the maximun value per pixel of n-input videos

  18 décembre 2016, par LighthouseZGZ

  Imagine a collection of short videos, each one showing a shooting star.

  I would like to get a composite video of all shooting stars. Not in sequence, at the same time. The (x,y) pixel of the nth frame in the output video should have the maximum value for that (x,y) pixel of the same frame in all the videos.

  I know how to do that using images and imagemagick :

  magick *.bmp -evaluate-sequence max output.bmp

  I need something similar for video. Frame by frame.

  Any help would be appreciated. Thanks.

• how to put a red frame before each video programmatically, when concatenating videos using ffmpeg

  7 février 2023, par Maifee Ul Asad

  To merge files with ffmpeg I'm creating a text file like this :

  


  file 'a.mkv'
file 'b.mkv'
file 'c.mkv'


  


  Then I'm running this command to concat these videos :

  


  ffmpeg -f concat -i file.txt -c copy merged.mkv


  


  But the thing is, I want to put red frame for three seconds in the middle of each video.

  


  Now I can get these videos' frame dimensions and create a video and modify the text file like this :

  


  file 'red.mkv'
file 'a.mkv'
file 'red.mkv'
file 'b.mkv'
file 'red.mkv'
file 'c.mkv'


  


  But this is not a programmatical approach, so is there any way I can concat videos and put red frames for three seconds (before every video) ?

  


  I want to generate that red frame video, on run time.