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• configure : Force pie for Android.

  25 juillet 2018, par Carl Eugen Hoyos

  configure : Force pie for Android.
  Position-independent executables are required since Lollipop.
  Reported-by : Mohammed Bey Ahmed Khernache
  

  • [DH] configure

• Efficient way to stream a sequence of frames

  3 juin 2020, par DoriHp 0

  I'm facing with an issue : I implemented a device to detect stranger for my home, which includes inputs from some IP camera and use a tensorflow model to process frame got from them.

  



  Now I want to build a dashboard (use Flask or Django - python framework as backend) to streaming the processed frames I got from the system, and if possible, do some transform on them (such as stack multi frames into one, etc), and run the server so I can watch it from distances. Currently, I'm sending frame by frame as independent images but it costs so much bandwidth. I read how h264 encoder work and felt very exicted about it. Now, the question is, how can I use h264 or any encoder like it transfer my data and reduce the bandwidth ?

  


• Ffmpeg does not properly convert videos when run as daemon

  20 janvier 2019, par DGoiko

  I’m using ffmpeg to convert and split videos from a Python process. When I run it from console as a normal user everything works as expected, however, if I run it as a daemon it produces the same amount of files but with silence in almost the whole file.

  This is the line I execute from python :

  def convert_to_ffmpeg(file, ffmpeg_folder, chunk_length):
  
      res = -1
  
      try:
  
          file_name = os.path.join(ffmpeg_folder, ntpath.basename(file) + ".flac")
  
          res = os.system("ffmpeg -i " + file + " -f segment -segment_time "+str(chunk_length)+" " + file_name + " -y  >/dev/null 2>&1")
  
      except Exception as e:
  
          raise MyException(code=210005, detalails=file, cause=e)
  
      if not res == 0:
  
          raise MyException(code=210004, detalails=str(res) + " - " + file)
  
      return file_name

  When I run it from a normal console it works as expected : it splits the video in chunks of "self._chunk_length" seconds.

  However, if I run the program using python-daemon with this code :

  if daemon_run:
  
      pid_file = check_unclean_exit(config['pidfile'], log)
  
  
  
      context = daemon.DaemonContext(
  
          working_directory=approot,
  
          umask=0o002,
  
          pidfile=pid_file,
  
      )
  
      context.signal_map = {
  
          signal.SIGTERM: programa_cleanup,
  
          signal.SIGHUP: 'terminate',
  
          # signal.SIGUSR1: reload_program_config,
  
      }
  
  
  
      with context:
  
          convert_to_ffmpeg("/foo/testfile.mkv", "/foo/ffmpeg", 40) 

  It produces EXACTLY the same chunks, however, most of the content of the chunks is just silence. It splits in the proper point, but doesn’t fill the contents of the audio output properly. Of course, no exception is thrown, as ffmpeg always returns 0

  I did even install a completly fresh Debian 9 into a virtual machine to discard problems with ffmpeg and my old-good computer’s setup.

  Of course this is a simplified example. The real thing is a multithread application which watches a directory for files to convert.