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• Last subprocess call not working in concatenation code with FFMPEG. How should I go about fixing this?

  28 November 2019, by S1mple

  clips = []
  
  
  
  #generates a list of mp4 files in a folder
  
  def clipFinder(CurrentDir, fileType):
  
      clips.clear()
  
      for r,d,f in os.walk(CurrentDir):
  
          for file in f:
  
              if fileType in file:
  
                  clips.append(r+file)
  
      random.shuffle(clips)
  
  
  
  #removes all files that have the string 'vod' in them as they cause problems during concatenation
  
  def removeVods(r):
  
      for f in clips:
  
          if 'vod' in clips:
  
              os.remove(r+f)
  
  
  
  #generates a string using the clips list to insert into the ffmpeg command
  
  def clipString():
  
      string = 'intermediate'
  
      clipList = []
  
      clipNum = 1
  
      for f in clips:
  
          clipList.append(string+str(clipNum)+'.ts'+'|')
  
          clipNum+=1
  
      string1 = ''.join(clipList)
  
      string2 = string1[0:len(string1)-1]
  
      return string2
  
  
  
  #concatenates the mp4 files in the clipString
  
  def concatFiles():
  
      clipFinder('***', '.mp4')
  
      removeVods('***')
  
      i = 0
  
      intermediates = []
  
      for f in clips:
  
          subprocess.call(['***', '-i', clips[i], '-c', 'copy', '-bsf:v', 'h264_mp4toannexb', '-f', 'mpegts', 'intermediate'+ str(i+1) +'.ts'])
  
          i += 1 
  
      clipsLength = len(clips)
  
      subprocess.call['***', '-i', '"concat:' + clipString() + '"', '-c', 'copy', '-bsf:a 
  
      aac_adtstoasc', 'output.mp4']

  I am trying to make a clip concatenator, but the last subprocess call won’t run and gives me no error. When I run the script the first FFmpeg call works fine and gives me my intermediate mp4 files, however, the second command, which works when I run it in terminal, does not work when I run it from python using subprocess.call.

  Problematic code:

  subprocess.call(['***', '-i', '"concat:' + clipString() + '"', '-c', 'copy', '-bsf:a aac_adtstoasc', 'output.mp4'])

  all places with * were paths such as: /davidscomputer/bin/ffmpeg/

• avfilter: always call ff_default_query_formats

  20 October 2023, by Niklas Haas

  avfilter: always call ff_default_query_formats
  Even if a query func is set. This is safe to do, because
  
  ff_default_query_formats is documented not to touch any filter lists
  
  that were already set by the query func.
  The reason to do this is because it allows us to extend
  
  AVFilterFormatsConfig without having to touch every filter in existence.
  
  An alternative implementation of this commit would be to explicitly add
  
  a `ff_default_query_formats` call at the end of every query_formats
  
  function, but that would end up functionally equivalent to this change
  
  while touching a whole lot more code paths for no reason.
  As a bonus, eliminates some code/logic duplication from this function.
  

  • [DH] libavfilter/avfiltergraph.c

• Cannot run ffmpeg in subproces.call

  27 June 2012, by Richard Knop

  So, I have a simple class where I am trying to save a string response from a terminal ffmpeg command into an object property:

  import os
  
  import subprocess
  
  
  
  class Movie(object):
  
  
  
      absolute_path = None
  
      movie_info = None
  
  
  
      def __init__(self, path):
  
          self.absolute_path = "%s/%s" % (os.getcwd(), path)
  
          if(os.path.exists(self.absolute_path) is False):
  
              raise IOError("File does not exist")
  
  
  
      def get_movie_info(self):
  
          ffmpeg_command = "ffmpeg -i %s" % self.absolute_path
  
          self.movie_info = subprocess.call(ffmpeg_command)
  
          print self.movie_info

  When I then run this command in cmd:

  import os
  
  import sys
  
  sys.path.append(os.getcwd())
  
  
  
  from Encode.Movie import Movie
  
  
  
  try:
  
      movie = Movie("tests/test_1.mpg")
  
      movie.get_movie_info()
  
  except IOError as e:
  
      print e

  I get this exception:

  richard@richard-desktop:~/projects/hello-python$ python main.py 
  
  Traceback (most recent call last):
  
    File "main.py", line 9, in <module>
  
      movie.get_movie_info()
  
    File "/home/richard/projects/hello-python/Encode/Movie.py", line 16, in get_movie_info
  
      self.movie_info = subprocess.call(ffmpeg_command)
  
    File "/usr/lib/python2.7/subprocess.py", line 493, in call
  
      return Popen(*popenargs, **kwargs).wait()
  
    File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
  
      errread, errwrite)
  
    File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
  
      raise child_exception
  
  OSError: [Errno 2] No such file or directory
  
  </module>

  The path is correct because when I do print self.absolute_path before subprocess.call(), I get:

  /home/richard/projects/hello-python/tests/test_1.mpg

  And this file exists.