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• Revision 8fb9f083f2 : Merge changes I0b51674f,I1ea6ebf9,I89076d93 into experimental * changes : lint

  14 août 2012, par John Koleszar

  Merge changes I0b51674f,I1ea6ebf9,I89076d93 into experimental * changes : lint_hunks : show style violations in the index intersect_diffs : split out diff classes ftfy : update to match current astyle rule

• opencv + opengl + ffmpeg ?

  4 août 2012, par JeiKei

  I'm trying to write a application that uses ffmpeg to play a video, opencv to analysis camera input data and opengl to show UI.

  The reason I want to use openGL is because opencv does not support transparent images for UI, also opencv does not support playing sound of a video.

  is there any tutorial for this ?

• Getting realtime output from ffmpeg to be used in progress bar (PyQt4, stdout)

  8 mars 2017, par Jason O'Neil

  I’ve looked at a number of questions but still can’t quite figure this out. I’m using PyQt, and am hoping to run ffmpeg -i file.mp4 file.avi and get the output as it streams so I can create a progress bar.

  I’ve looked at these questions :
  Can ffmpeg show a progress bar ?
  http://stackoverflow.com/questions/1606795/catching-stdout-in-realtime-from-subprocess

  I’m able to see the output of a rsync command, using this code :

  import subprocess, time, os, sys
  
  
  
  cmd = "rsync -vaz -P source/ dest/"
  
  p, line = True, 'start'
  
  
  
  
  
  p = subprocess.Popen(cmd,
  
                       shell=True,
  
                       bufsize=64,
  
                       stdin=subprocess.PIPE,
  
                       stderr=subprocess.PIPE,
  
                       stdout=subprocess.PIPE)
  
  
  
  for line in p.stdout:
  
      print("OUTPUT>>> " + str(line.rstrip()))
  
      p.stdout.flush()

  But when I change the command to ffmpeg -i file.mp4 file.avi I receive no output. I’m guessing this has something to do with stdout / output buffering, but I’m stuck as to how to read the line that looks like

  frame=   51 fps= 27 q=31.0 Lsize=     769kB time=2.04 bitrate=3092.8kbits/s

  Which I could use to figure out progress.

  Can someone show me an example of how to get this info from ffmpeg into python, with or without the use of PyQt (if possible)

  ---

  EDIT :
  I ended up going with jlp’s solution, my code looked like this :

  #!/usr/bin/python
  
  import pexpect
  
  
  
  cmd = 'ffmpeg -i file.MTS file.avi'
  
  thread = pexpect.spawn(cmd)
  
  print "started %s" % cmd
  
  cpl = thread.compile_pattern_list([
  
      pexpect.EOF,
  
      "frame= *\d+",
  
      '(.+)'
  
  ])
  
  while True:
  
      i = thread.expect_list(cpl, timeout=None)
  
      if i == 0: # EOF
  
          print "the sub process exited"
  
          break
  
      elif i == 1:
  
          frame_number = thread.match.group(0)
  
          print frame_number
  
          thread.close
  
      elif i == 2:
  
          #unknown_line = thread.match.group(0)
  
          #print unknown_line
  
          pass

  Which gives this output :

  started ffmpeg -i file.MTS file.avi
  
  frame=   13
  
  frame=   31
  
  frame=   48
  
  frame=   64
  
  frame=   80
  
  frame=   97
  
  frame=  115
  
  frame=  133
  
  frame=  152
  
  frame=  170
  
  frame=  188
  
  frame=  205
  
  frame=  220
  
  frame=  226
  
  the sub process exited

  Perfect !