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• Ignore streams when finding stream info

  17 mars 2018, par CSNewman

  I’m trying to speed up the start of ffmpeg when processing my live stream, and have narrowed down the issue to the ‘avformat_find_stream_info’ function. The source I’m trying to process seems to have a number of streams that ffmpeg is unable to determine what they are and therefore spends a while trying to find information about them (The entire analyse window). I know ahead of time that I only want to find information about stream #0:0 and #0:1, and I will be disregarding the other streams anyways.

  I managed to work around this using the API by setting the number of streams before the find information call and then restoring the value afterwards.

  inputContext->nb_streams = (uint) 2;
  
  if (ffmpeg.avformat_find_stream_info(inputContext, null) < 0)
  
  {
  
      throw new InvalidOperationException("Could not read stream information.");
  
  }
  
  inputContext->nb_streams = oldSize;

  However, I would prefer to use the CLI interface of ffmpeg.

  My current command

  ffmpeg -find_stream_info false -i http://192.168.1.112:5004/auto/v1 -c copy -map 0:v:0 -map 0:a:0 -ignore_unknown   -f hls -hls_flags delete_segments  -segment_list playlist.m3u8 -segment_list_type hls -segment_list_size 10 -segment_list_flags +live -segment_time 10 -f segment stream%%05d.ts

  Giving the following input (Unneeded logging removed)

  [mpeg2video @ 000001ce79423440] Invalid frame dimensions 0x0.
  
      Last message repeated 9 times
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 5 (Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 6 (Unknown: none ([11][0][0][0] / 0x000B)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 7 
  
  (Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  [mpegts @ 000001ce7941b740] Could not find codec parameters for stream 8 
  
  (Unknown: none ([5][0][0][0] / 0x0005)): unknown codec
  
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  
  Input #0, mpegts, from 'http://192.168.1.112:5004/auto/v1':
  
    Duration: N/A, start: 91296.182311, bitrate: N/A
  
    Program 4165
  
      Stream #0:0[0x65]: Video: mpeg2video (Main) ([2][0][0][0] / 0x0002), yuv420p(tv, top first), 704x576 [SAR 16:11 DAR 16:9], 25 fps, 25 tbr, 90k tbn, 50 tbc
  
      Stream #0:1[0x66](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, stereo, s16p, 256 kb/s
  
      Stream #0:2[0x6a](eng): Audio: mp2 ([3][0][0][0] / 0x0003), 48000 Hz, mono, s16p, 64 kb/s (visual impaired) (dependent)
  
      Stream #0:3[0x69](eng): Subtitle: dvb_subtitle ([6][0][0][0] / 0x0006)
  
      Stream #0:4[0x98]: Audio: mp2 ([6][0][0][0] / 0x0006), 48000 Hz, stereo, s16p, 128 kb/s
  
      Stream #0:5[0x1c21]: Unknown: none ([11][0][0][0] / 0x000B)
  
      Stream #0:6[0x1c33]: Unknown: none ([11][0][0][0] / 0x000B)
  
      Stream #0:7[0x1bbf]: Unknown: none ([5][0][0][0] / 0x0005)
  
      Stream #0:8[0x1bc1]: Unknown: none ([5][0][0][0] / 0x0005)

  I’m unsure if there’s a way to achieve the same functionality with the CLI, however I’m open changing how my setup works.

  One idea that I considered was running two ffmpeg instances, one to strip the unneeded streams (and not find the stream info) and then have another that takes that stripped stream and performs the rest of the functionality.

  Any insight here would be grateful, thanks in advance.

• 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 ?