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• Programmatically cut video in java

  27 janvier 2016, par DaaarK

  I used opencv for finding frame similar frames between video files and I need cut that file,my app normal finding similar frames, but how to cut video file programmatically
  Who know how to cut video in java, I used ffmpeg with

    String cmd = "ffmpeg -i res/movie2.mp4 -ss " + start + " -to " + end + " -y outt.mp4 ";
  
              System.out.println(cmd);
  
              Process process = Runtime.getRuntime().exec(cmd);
  
              process.waitFor();
  
  
  
              BufferedReader stdInput = new BufferedReader(new InputStreamReader(process.getInputStream()));
  
              BufferedReader stdError = new BufferedReader(new InputStreamReader(process.getErrorStream()));
  
              System.out.println("Here is the standard output of the command:\n");
  
  
  
              String s;
  
              while ((s = stdInput.readLine()) != null)
  
                  System.out.println(s);
  
  
  
              System.out.println("Here is the standard error of the command (if any):\n");
  
  
  
              while ((s = stdError.readLine()) != null)
  
                  System.out.println(s);

  But it’s used very more cpu after it I see Xuggler but can’t fount about cutting video.Who know please help me

• Anomalie #2363 : Le surtitre ne s’affiche pas

  10 octobre 2011, par Fil Up

  par défaut ça devrait être visible si quelqu’un a saisi un surtitre ; à corriger donc dans la css standard, pas dans perso…

• Finding corrupted videos with opencv

  16 septembre 2022, par tusker

  I have huge video dataset (about 500000 16 frame length clips). Some of the videos produce messages like

  


  [mpeg4 @ 0x561b46a44b80] marker does not match f_code
[mpeg4 @ 0x561b480c0740] Error at MB: 4718
[mpeg4 @ 0x561b4811b640] header damaged


  


  I want to find which videos cause the problem.
  
First I tried with this https://superuser.com/questions/100288/how-can-i-check-the-integrity-of-a-video-file-avi-mpeg-mp4 solution, but I got nothing in the error files.

  


  My second idea was to read the first image of a video and if it throws an error, save the filename to a file. However, it seems this is not an error message : although the messages appeared on console, read returned with success=True.

  


  Then I tried to print the filenames to standard error (where the warning messages also go), saving it to a file and do some postprocessing to extract the videos which has problem.

  


  import os
from tqdm import tqdm
import sys

folder = '/path/to/videos'
for f in tqdm(os.listdir(folder)):
  sys.stderr.write('BEFORE VIDCAP ' + f + '\n')
  vidcap = cv2.VideoCapture(os.path.join(folder,f))
  sys.stderr.write('BETWEEN VIDCAP AND SUCCESS' + f + '\n')

  success, image = vidcap.read()
  sys.stderr.write('AFTER SUCCESS ' + f + '\n')


  


  However, the standard error outputs in the following order :

  


  AFTER SUCCESS
[mpeg ...] 
[mpeg ...]
...
BEFORE VIDCAP


  


  It doesn't make sense how can it happen in this order, some broken videos should be seen somewhere between BEFORE and AFTER. (And the ones following or preceding are not broken neither if I try to open them individually.)

  


  My last idea was to create for every video a file, making it as the stderr and check the non-empty files. (I know it's insanely unefficient, but I didn't have any other idea.)

  


  for f in os.listdir(folder):
  sys.stderr = open(f + '.txt', 'w')
  vidcap = cv2.VideoCapture(os.path.join(folder,f))
  success, image = vidcap.read()


  


  This doesn't work also, all the error files are empty, although the messages still appear on standard error.

  


  ---

  


  So my questions are the following :

  


  

  1. What would be an efficient solution for this problem ?

  


  2. How is this order of outputs (first code example) possible ? There is some parallelism under the hood ?

  


  3. Where are this messages going if not to the standard error (second code example) ? If yes, why are they printed to the console instead of the specified error file ?