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• Issues in python based ffmpeg operation

  28 septembre 2021, par Adideva98

  I am trying to write a script that would automatically take duration values and chop an audio file into smaller splits. To do this I have saved all my start times and durations in a list. And this is the code I am trying to run.

  


  for k in range(0,len(start_time)):
  s=start_time[k]
  e=Duration[k]
  filename = "output%d.mp3" % (k)
  !ffmpeg -i Audio.mp3 -ss s -t e -acodec copy filename
  k=k+1


  


  On running this I get the following error
Invalid duration specification for ss: s
I suspect that this error arises because of the fact that since I am using lists to call elements, the time stamp comes with quotes on both sides. Secondly, I am not sure how to specify the filename, such that each created split has the name of this format Output_1.mp3 and so on. The integer will be an identifier of the split. What could be possible fixes for this piece of code ? Please note that I am running this on Google Colab.

  


• ffmpeg-python extracting frames from camera in batches

  28 juin 2021, par Alter

  When I read frames from my camera using ffmpeg-python, the frames appear to come in batches of 4- why is this, and how can I change it ?

  


  I would like to get one frame at a time... I'm also hoping to avoid faking the frame times using the -r option

  


  

  


  In the image above, I'm recording at 30fps. The 120ms pause followed by 3 quick frames suggests that the frames are coming in batches of 4.

  


  Partial code

  


  reader = (ffmpeg
    .input('/dev/video0', framerate=fps)
    .output('pipe:', format='rawvideo', pix_fmt='rgb24')
    .run_async(pipe_stdout=True))
    
while True:
    start = time.time_ns()
    frame = reader.stdout.read(width * height * 3)
    logger.debug(f'frame read time: {(time.time_ns() - start)/1e6}ms')
    # Do something else
    logger.debug(f'frame capture loop: {(time.time_ns() - start)/1e6}ms')


  


• Java process use more memory than VisualVM shows

  16 juillet 2021, par Dinexpod

  my java application works 1 day,
(I use different libs for processing photo like ffmpeg, javacv, javacpp)
and then I see that my app use 9,5Gb RAM.

  


  system monitoring tools

  


  I don't understand why my app use so a lot of memory.

  


  I set -Xmx6G

  


  In VisualVM I see that heap space size 188M

  


  heap space in visualVM

  


  Meta Space use 141M

  


  metaspace in visualVM

  


  May be this helps

  


  allocated bytes in visualVM

  


  I read articles that Java use more RAM than heap space because there are JIT, Heap space, meta space, code, ant etc. But 9.5Gb is a lot of on my mind

  


  Edited :

  


  

  • Yes my app some times have exceptions java.lang.OutOfMemoryError : Java heap space