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• FFMPEG MP3 file size much larger than expected on Windows 10

  8 avril 2018, par The Gora

  I’ve been using FFMPEG on Windows to :

  1. Convert iTunes M4A files to MP3s (with a bit rate of 128k) ; and
  2. Create 30 sec sample MP3s of the above MP3s (same bit rate).

  When I run FFMEG on a Windows 7 64 bit machine, the size of the MP3s (both for 1. & 2.) is in line with the rough calculation of :

  (Audio length in seconds) X (Bit rate)

  For example, a 4 minute audio yields an approx. 3.7MB MP3 file ; a 30 second sample MP3 is approx. 470KB.

  However when I run the same FFMPEG binary (copied from the Windows 7 machine) on a Windows 10 64 bit machine, all of the MP3s (both for 1. and for 2.) are inflated by approx 5MB. I’m using the same batch file on both machines to execute FFMEG with the required parameters, so pretty confident the difference is not down to user error.

  My questions are :

  1. Why is there this apparent 5MB overhead on Windows 10 ? and more importantly ;
  2. What can I do to remove this ?

  The large file size is a problem as the sample MP3s are to be put on a website for people to listen to a snippet of the song, and the webpage with multiple tags takes a long time to load completely (several minutes).

  Here is the version and lib info :

  ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
 built with gcc 7.2.0 (GCC)
 configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
 libavutil      55. 78.100 / 55. 78.100
 libavcodec     57.107.100 / 57.107.100
 libavformat    57. 83.100 / 57. 83.100
 libavdevice    57. 10.100 / 57. 10.100
 libavfilter     6.107.100 /  6.107.100
 libswscale      4.  8.100 /  4.  8.100
 libswresample   2.  9.100 /  2.  9.100
 libpostproc    54.  7.100 / 54.  7.100

  And here are the command lines I’m using :

  1. ffmpeg -i input.m4a -id3v2_version 3 -b:a 128k -output.mp3
  2. ffmpeg -i input.m4a -ss 30 -t 30 -af "afade=in:st=30:d=5,afade=out:st=55:d=5" -id3v2_version 3 -b:a 128k -output.mp3

• ValueError : I/O operation on closed file when making animation

  3 juillet 2018, par user3851187

  I am using matplotlib and ffmpeg to do some animations. I usually code on a remote server because the code runs faster ; we are having some issues making animations on the remote server. Here is an example of code that works perfectly on my local mac but does not work remotely.

  import matplotlib as mpl
  
  mpl.use('agg')
  
  import matplotlib as mpl 
  
  from matplotlib import animation
  
  import pylab
  
  
  
  def init():
  
      pylab.plot(pylab.arange(10), [0]*10)
  
  
  
  def redraw(frame):
  
      pylab.plot(pylab.arange(10), pylab.arange(10) * frame)
  
  
  
  fig = pylab.figure()
  
  ani = animation.FuncAnimation(fig, redraw, frames=10, interval=1000, init_func=init)
  
  ani.save('animation.mp4')

  I get the animation I want on my local machine (macOS Sierra). When I run it on the remote host (Debian GNU/Linux 8 (jessie)), I get the following error message after 5 frames

  Traceback (most recent call last):
  
    File "animation.py", line 14, in <module>
  
      ani.save('animation.mp4')
  
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/animation.py", line 1200, in save
  
      writer.grab_frame(**savefig_kwargs)
  
    File "/usr/lib/python2.7/contextlib.py", line 35, in __exit__
  
      self.gen.throw(type, value, traceback)
  
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/animation.py", line 241, in saving
  
      self.finish()
  
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/animation.py", line 367, in finish
  
      self.cleanup()
  
    File "/usr/local/lib/python2.7/dist-packages/matplotlib/animation.py", line 405, in cleanup
  
      out, err = self._proc.communicate()
  
    File "/usr/local/lib/python2.7/dist-packages/subprocess32.py", line 724, in communicate
  
      stdout, stderr = self._communicate(input, endtime, timeout)
  
    File "/usr/local/lib/python2.7/dist-packages/subprocess32.py", line 1535, in _communicate
  
      orig_timeout)
  
    File "/usr/local/lib/python2.7/dist-packages/subprocess32.py", line 1591, in _communicate_with_poll
  
      register_and_append(self.stdout, select_POLLIN_POLLPRI)
  
    File "/usr/local/lib/python2.7/dist-packages/subprocess32.py", line 1570, in register_and_append
  
      poller.register(file_obj.fileno(), eventmask)
  
  ValueError: I/O operation on closed file
  
  </module>

  My local machine uses matplotlib version 2.0.0 ; the remote machine uses matplotlib version 2.2.2

  On my local machine I have ffmpeg version 3.2.4

  $ ffmpeg -version
  
  ffmpeg version 3.2.4 Copyright (c) 2000-2017 the FFmpeg developers
  
  built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
  
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.2.4 --enable-shared - 
  
  -enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables 
  
  --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  
  libavutil      55. 34.101 / 55. 34.101
  
  libavcodec     57. 64.101 / 57. 64.101
  
  libavformat    57. 56.101 / 57. 56.101
  
  libavdevice    57.  1.100 / 57.  1.100
  
  libavfilter     6. 65.100 /  6. 65.100
  
  libavresample   3.  1.  0 /  3.  1.  0
  
  libswscale      4.  2.100 /  4.  2.100
  
  libswresample   2.  3.100 /  2.  3.100
  
  libpostproc    54.  1.100 / 54.  1.100 

  On the remote host i have ffmpeg version 4.0.1

  ffmpeg -version
  
  ffmpeg version 4.0.1 Copyright (c) 2000-2018 the FFmpeg developers
  
  built with gcc 4.9.2 (Debian 4.9.2-10+deb8u1)
  
  configuration: --prefix=/usr/local
  
  libavutil      56. 14.100 / 56. 14.100
  
  libavcodec     58. 18.100 / 58. 18.100
  
  libavformat    58. 12.100 / 58. 12.100
  
  libavdevice    58.  3.100 / 58.  3.100
  
  libavfilter     7. 16.100 /  7. 16.100
  
  libswscale      5.  1.100 /  5.  1.100
  
  libswresample   3.  1.100 /  3.  1.100

  If I recall correctly I installed ffmpeg locally through homebrew ; I have the anaconda distribution of python. On the remote machine we have the default version of python that comes with Jessie ; I’m not sure how the sysadmin installed ffmpeg.

  I am by no means an expert on ffmpeg, but I have generally never had issues with making animations in matplotlib on my local machine and I would really like to be able to make videos more quickly on the remote machine. Any help would be appreciated !

  Edit
  On the remote machine, the animation works if I use avconv as the writer instead of ffmpeg. I installed avconv locally...which led me to get the same ffmpeg issues locally (probably due to updating shared dependencies). However, I uninstalled ffmpeg and reinstalled it with x264 codec enables Animations in ipython (jupyter) notebook - ValueError : I/O operation on closed file

• FFMPEG Compilation and Video Thumbnail Issues [on hold]

  2 janvier 2016, par P. Paul

  I have compiled FFMPEg on a Linux, Centos machine according to the guide in here https://trac.ffmpeg.org/wiki/CompilationGuide/Ubuntu , and the auto video thumbnail creation command in here https://trac.ffmpeg.org/wiki/Create%20a%20thumbnail%20image%20every%20X%20seconds%20of%20the%20video

  The problems are...

  1- When I use ffmpeg or ffmpeg -version command to check if ffmpeg has been installed I get the error message, "Command not found". But when I check for ffmpeg directory "~/ffmpeg_sources" is found and the machine says, "is a directory".

  2- Also, I did a test and upload video to the site to see if the video’s thumbnail will be automatically generated, but it didn’t show any thumbnail.

  Any help would be greatly appreciated.

  Thanks in advance !