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• ValueError : I/O operation on closed file with ffmpeg

  22 mars 2018, par AstroCoda

  I’m trying to get this (minimal working example) code to compile in a virtual environment on Anaconda which I’ve set up in a supercomputing cluster :

  import numpy as np
  
  import matplotlib
  
  matplotlib.use("Agg")
  
  import matplotlib.pyplot as plt
  
  import matplotlib.animation as manimation
  
  
  
  FFMpegWriter = manimation.writers['ffmpeg']
  
  metadata = dict(title='Movie Test', artist='Matplotlib',
  
              comment='Movie support!')
  
  writer = FFMpegWriter(fps=15, metadata=metadata)
  
  
  
  fig = plt.figure()
  
  l, = plt.plot([], [], 'k-o')
  
  
  
  plt.xlim(-5, 5)
  
  plt.ylim(-5, 5)
  
  
  
  x0, y0 = 0, 0
  
  
  
  with writer.saving(fig, "writer_test.mp4", 100):
  
      for i in range(100):
  
          x0 += 0.1 * np.random.randn()
  
          y0 += 0.1 * np.random.randn()
  
          l.set_data(x0, y0)
  
          writer.grab_frame()

  The thing is, this code works absolutely fine on my local machine (MacOSX) - Anaconda distribution ; Python 2.7 ; same matplotlib and numpy version, and I have ffmpeg on Anaconda ; I have ffmpeg on the cluster as well, albeit at a different version to the one on Python (but no issue with this on my local machine). When I run the code on the cluster, I get :

  Traceback (most recent call last):
  
    File "movie_test.py", line 25, in <module>
  
      writer.grab_frame()
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/contextlib.py", line 35, in __exit__
  
      self.gen.throw(type, value, traceback)
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/matplotlib/animation.py", line 241, in saving
  
      self.finish()
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/matplotlib/animation.py", line 367, in finish
  
      self.cleanup()
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/matplotlib/animation.py", line 405, in cleanup
  
      out, err = self._proc.communicate()
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/subprocess32.py", line 927, in communicate
  
      stdout, stderr = self._communicate(input, endtime, timeout)
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/subprocess32.py", line 1713, in _communicate
  
      orig_timeout)
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/subprocess32.py", line 1769, in _communicate_with_poll
  
      register_and_append(self.stdout, select_POLLIN_POLLPRI)
  
    File "~/anaconda2/envs/test_movie/lib/python2.7/site-packages/subprocess32.py", line 1748, in register_and_append
  
      poller.register(file_obj.fileno(), eventmask)
  
  ValueError: I/O operation on closed file
  
  </module>

  All the searches I’ve made correspond to relatively simple text write in/out operations, but not for videos. Thanks in advance for the help !

• Catching ffmpeg errors in Tensorflow

  12 avril 2018, par lollercoaster

  Currently I make extensive use of tensorflow’s ffmpeg interface :

  from tensorflow.contrib.framework.python.ops import audio_ops as contrib_audio
  
  from tensorflow.python.ops import io_ops
  
  from tensorflow.contrib import ffmpeg
  
  
  
  def load(mp3_path):
  
      with tf.name_scope("loading") as scope:
  
          audio_binary = tf.read_file(mp3_path)
  
          waveform = tf.reshape(ffmpeg.decode_audio(
  
              audio_binary, file_format='mp3', 
  
              samples_per_second=44100, channel_count=1), [-1])
  
          return waveform

  This is wonderful, but sometimes (well, a lot) I get errors like this when looping through a bunch of files to create TFRecord files :

  [mp3 @ 0xdd4400] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [mp3 @ 0xf2e440] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [mp3 @ 0x202bf40] invalid new backstep -1
  
  [mp3 @ 0x15c5440] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [mp3 @ 0x1752460] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [mp3 @ 0x1f10160] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [mp3 @ 0x1a16dc0] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  [mp3 @ 0x9f2c80] Header missing
  
  Error while decoding stream #0:0: Invalid data found when processing input

  which shows up in stdout while running this Python script.

  I’d like to catch these somehow ! And prevent the rest of my loop from continuing if the data I’m reading is invalid.

  Currently, these errors just happen and the script happily keeps running, which is probably not the way it should work.

  I’m not making use of the Dataset API for this, so these direct session.run(waveform_op) calls should throw and Exception or something when parsing fails !

  Anyone know how I can do this ?

• Async Javascript function returns undefined

  14 avril 2018, par Leon Wright

  I am trying to run this function but the it keeps returning undefined when I explicitly hardcode the return value.

  const splitVideo = async (sid, video, part) => {
  
      let framesLocation =`${process.cwd()}/${dirs.videoFrames}/${sid}_${part}`;
  
  
  
      console.log(fs.existsSync(framesLocation));
  
  
  
      if(!fs.existsSync(framesLocation)) {
  
          console.log("making dir");
  
          f.s.mkdirSync(framesLocation);
  
      }
  
  
  
      ffmpeg(video)
  
          .on('end', () => {
  
               return "done";
  
           })
  
           .on('error', (err) => {
  
               throw err;
  
           })
  
           .screenshots({
  
                timestamps: [1,2],
  
                filename: `${sid}_${part}/frame-%s.png`,
  
                folder: `${process.cwd()}/${dirs.videoFrames}`
  
           });
  
  };

  Please help this is very frustrating.