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• Which release of ffmpeg is used in the book "Understanding FFmpeg with source code : FFMPEG Fundamentals" ?

  28 septembre 2021, par user3344036

  Just bought the book "Understanding FFmpeg with source code : FFMPEG Fundamentals" from Amazon. I have downloaded ffmpeg release 4.4, but the code has been different from that in the book. Just wondering which release the author was using, can anyone help ?

  


• Passing python's file like object to ffmpeg via subprocess

  3 juillet 2012, par tejinderss

  I have a django FileField, which i use to store wav files on the Amazon s3 server. I have set up the celery task to read that file and convert it to mp3 and store it to another FileField. Problem i am facing is that i am unable to pass the input file to ffmpeg as the file is not the physical file on the hard disk drive. To circumvent that, i used stdin to feed the input stream of the file with the django's filefield. Here is the example :

  output_file = NamedTemporaryFile(suffix='.mp3')
  
  subprocess.call(['ffmpeg', '-y', '-i', '-', output_file.name], stdin=recording_wav)

  where recording_wav file is : , which is actually stored on the amazon s3 server.
  The error for the above subprocess call is :

  AttributeError: 'cStringIO.StringO' object has no attribute 'fileno'

  How can i do this ? Thanks in advance for the help.

  Edit :

  Full traceback :

  [2012-07-03 04:09:50,336: ERROR/MainProcess] Task api.tasks.convert_audio[b7ab4192-2bff-4ea4-9421-b664c8d6ae2e] raised exception: AttributeError("'cStringIO.StringO' object has no attribute 'fileno'",)
  
  Traceback (most recent call last):
  
    File "/home/tejinder/envs/tmai/local/lib/python2.7/site-packages/celery/execute/trace.py", line 181, in trace_task
  
      R = retval = fun(*args, **kwargs)
  
    File "/home/tejinder/projects/tmai/../tmai/apps/api/tasks.py", line 56, in convert_audio
  
      subprocess.Popen(['ffmpeg', '-y', '-i', '-', output_file.name], stdin=recording_wav)
  
    File "/usr/lib/python2.7/subprocess.py", line 672, in __init__
  
      errread, errwrite) = self._get_handles(stdin, stdout, stderr)
  
    File "/usr/lib/python2.7/subprocess.py", line 1043, in _get_handles
  
      p2cread = stdin.fileno()
  
    File "/home/tejinder/envs/tmai/local/lib/python2.7/site-packages/django/core/files/utils.py", line 12, in <lambda>
  
      fileno = property(lambda self: self.file.fileno)
  
    File "/home/tejinder/envs/tmai/local/lib/python2.7/site-packages/django/core/files/utils.py", line 12, in <lambda>
  
      fileno = property(lambda self: self.file.fileno)
  
  AttributeError: &#39;cStringIO.StringO&#39; object has no attribute &#39;fileno&#39;
  
  </lambda></lambda>

• why ffmpeg starts many processes

  29 octobre 2020, par james

  I have a doubt about the functioning of the ffmpeg program, I noticed that after starting the program on a 4gb memory raspberry pi4 many processes are started, is it normal or is there something wrong with my program ? I remember that on an amazon ec2 instance by controlling with htop only one process was created

  


  Code I used

  


  from subprocess import Popen

ffmpeg_process = Popen(["ffmpeg", "-hide_banner", "-loglevel", "panic", "-y", "-i", "./video/video1.mp4",
                        "-vcodec", "h264", "-acodec", "mp3", "./video/video2.mp4"],
                        start_new_session=True)

ffmpeg_process.wait()