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• mpeg12dec : Extract CC user data into frame side data

  26 novembre 2013, par John Stebbins

  mpeg12dec : Extract CC user data into frame side data
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] doc/APIchanges
  • [DBH] libavcodec/mpeg12dec.c
  • [DBH] libavutil/frame.h
  • [DBH] libavutil/version.h

• Unable to save Matplotlib animations using ffmpeg

  23 décembre 2017, par jtpointon

  I have installed ffmpeg and added it to path, and checked it works in command prompt, but I am still unable to save animations. I have tried creating a sin wave that will animate when I don’t try to save it, but throws an error when I do to demonstrate ;

  from __future__ import division
  
  
  
  import numpy as numpy
  
  from matplotlib import pyplot as pyplot
  
  from matplotlib import animation
  
  
  
  fig = pyplot.figure()
  
  ax = pyplot.axes(xlim=(0, 2), ylim=(-2, 2))
  
  line, = ax.plot([], [], lw=2)
  
  
  
  def init():
  
      line.set_data([], [])
  
      return line,
  
  
  
  def animate(i):
  
      x = numpy.linspace(0, 2, 1000)
  
      y = numpy.sin(2 * numpy.pi * (x - 0.01 * i))
  
      line.set_data(x, y)
  
      return line,
  
  
  
  anim = animation.FuncAnimation(fig, animate, init_func=init, frames=200, 
  
      interval=20, blit=True, repeat=False)
  
  
  
  FFwriter = animation.FFMpegWriter()
  
  anim.save('animation_testing.mp4', writer = FFwriter)
  
  
  
  pyplot.show()

  When I try to run this it throws the same errors over and over again, I assume as it iterates through each frame ;

  Traceback (most recent call last):
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\backends\backend_wx.py", line 212, in _on_timer
  
      TimerBase._on_timer(self)
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\backend_bases.py", line 1273, in _on_timer
  
      ret = func(*args, **kwargs)
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\animation.py", line 910, in _step
  
      still_going = Animation._step(self, *args)
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\animation.py", line 769, in _step
  
      self._draw_next_frame(framedata, self._blit)
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\animation.py", line 787, in _draw_next_frame
  
      self._pre_draw(framedata, blit)
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\animation.py", line 800, in _pre_draw
  
      self._blit_clear(self._drawn_artists, self._blit_cache)
  
    File "c:\users\james\appdata\local\enthought\canopy\user\lib\site-
  
  packages\matplotlib\animation.py", line 840, in _blit_clear
  
      a.figure.canvas.restore_region(bg_cache[a])
  
  KeyError: 

  Since it mentioned an error in _blit_clear I tried changing blit to False in FuncAnimation, but then it wouldn’t animate in the pyplot.show() when I didn’t try to save.

  I’m unsure as to where the error could be and so can’t work out how to fix this.

  I’m using Windows 10, python 2.7.6 and matplotlib version 1.4.2

  Many Thanks !

• Cannot save animation in matplotlib : Windows permission denied

  13 mai 2015, par Vladimir

  I’ve been trying for a day long to sort this out, checking similar threads but with no success.
  Stretch’s Cannot save matplotlib animation with ffmpeg helped with previous errors (I had ffmpeg path wrong), but I kept getting Access denied after fixing it.

  My ffmpeg binary is on C:\ffmpeg\bin

  A nice alternative would be to able to export gif files, but I keep getting an ascii error with imagemagick. I think both problems are related, so I wanted to sort out the ffmpeg first.

  I think the problem might have to do with the fact I’m working with Canopy (in Windows 8 64bit), which pretty much hegemonized my path variable and broke some things along the way (e.g. I can’t open IDLE since I installed Canopy, didn’t tried to fix that yet). As I fixed things along the way I found at least 3 distinct path variables, all of which I updated : windows advanced settings path (set manually), windows console path (set via console with setx), and sys.path (set or checked at runtime), adding ";C:\ffmpeg\bin", where ffmpeg effectively is. Regardless I sort out the problem or not, I would like to learn which of these environment variables are relevant for what, I find it very confusing.

  The code is the following :

  # -*- coding: utf-8 -*-
  
  import sys
  
  import numpy as np
  
  from matplotlib import pyplot as plt
  
  from matplotlib import animation
  
  plt.rcParams['animation.ffmpeg_path'] = r'C:\ffmpeg\bin'
  
  if r'C:\ffmpeg\bin' not in sys.path: sys.path.append(r'C:\ffmpeg\bin')
  
  
  
  fig = plt.figure()
  
  ax = plt.axes(xlim=(0, 2), ylim=(-2, 2))
  
  line, = ax.plot([], [], lw=2)
  
  
  
  def init():
  
      line.set_data([], [])
  
      return line,
  
  
  
  def animate(i):
  
      x = np.linspace(0, 2, 1000)
  
      y = np.sin(2 * np.pi * (x - 0.01 * i))
  
      line.set_data(x, y)
  
      return line,
  
  
  
  anim = animation.FuncAnimation(fig, animate, init_func=init, frames=200, interval=20, blit=True)
  
  plt.show()
  
  
  
  # This case generates Windows err: Access Denied
  
  FFwriter = animation.FFMpegWriter()
  
  # anim.save(r'C:\basic_animation.mp4', writer = FFwriter, fps=30)
  
  
  
  # This case generates UnicodeDecodeError:'ascii' codec can't decode byte 0xa0 in position 3
  
  # anim.save(r'C:\animation.gif', writer='imagemagick', fps=30)

  The traceback for anim.save(r'C:\basic_animation.mp4', writer = FFwriter, fps=30) :

  %run "C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py"
  
  ---------------------------------------------------------------------------
  
  WindowsError                              Traceback (most recent call last)
  
  C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py in <module>()
  
       27 # This case generates Windows err: Access Denied
  
       28 FFwriter = animation.FFMpegWriter()
  
  ---> 29 anim.save(r'C:\basic_animation.mp4', writer = FFwriter, fps=30)
  
       30 
  
       31 # This case generates UnicodeDecodeError:'ascii' codec can't decode byte 0xa0 in position 3
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
  
      759         # since GUI widgets are gone. Either need to remove extra code to
  
      760         # allow for this non-existant use case or find a way to make it work.
  
  --> 761         with writer.saving(self._fig, filename, dpi):
  
      762             for data in zip(*[a.new_saved_frame_seq()
  
      763                               for a in all_anim]):
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.5.2.2785.win-x86_64\lib\contextlib.pyc in __enter__(self)
  
       15     def __enter__(self):
  
       16         try:
  
  ---> 17             return self.gen.next()
  
       18         except StopIteration:
  
       19             raise RuntimeError("generator didn't yield")
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in saving(self, *args)
  
      184         '''
  
      185         # This particular sequence is what contextlib.contextmanager wants
  
  --> 186         self.setup(*args)
  
      187         yield
  
      188         self.finish()
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in setup(self, fig, outfile, dpi, *args)
  
      174         # Run here so that grab_frame() can write the data to a pipe. This
  
      175         # eliminates the need for temp files.
  
  --> 176         self._run()
  
      177 
  
      178     @contextlib.contextmanager
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in _run(self)
  
      202                                       stdout=output, stderr=output,
  
      203                                       stdin=subprocess.PIPE,
  
  --> 204                                       creationflags=subprocess_creation_flags)
  
      205 
  
      206     def finish(self):
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.5.2.2785.win-x86_64\lib\subprocess.pyc in __init__(self, args, bufsize, executable, stdin, stdout, stderr, preexec_fn, close_fds, shell, cwd, env, universal_newlines, startupinfo, creationflags)
  
      707                                 p2cread, p2cwrite,
  
      708                                 c2pread, c2pwrite,
  
  --> 709                                 errread, errwrite)
  
      710         except Exception:
  
      711             # Preserve original exception in case os.close raises.
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.5.2.2785.win-x86_64\lib\subprocess.pyc in _execute_child(self, args, executable, preexec_fn, close_fds, cwd, env, universal_newlines, startupinfo, creationflags, shell, to_close, p2cread, p2cwrite, c2pread, c2pwrite, errread, errwrite)
  
      955                                          env,
  
      956                                          cwd,
  
  --> 957                                          startupinfo)
  
      958             except pywintypes.error, e:
  
      959                 # Translate pywintypes.error to WindowsError, which is
  
  
  
  WindowsError: [Error 5] Acceso denegado 
  
  </module>

  The traceback for anim.save(r'C:\animation.gif', writer='imagemagick', fps=30) :

  In [8]: %run "C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py"
  
  ---------------------------------------------------------------------------
  
  UnicodeDecodeError                        Traceback (most recent call last)
  
  C:\Users\Yahveh\Documents\Vlad\Investigacion\animation saving.py in <module>()
  
       30 
  
       31 # This case generates UnicodeDecodeError:'ascii' codec can't decode byte 0xa0 in position 3
  
  ---> 32 anim.save(r'C:\animation.gif', writer='imagemagick', fps=30)
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
  
      765                     # TODO: Need to see if turning off blit is really necessary
  
      766                     anim._draw_next_frame(d, blit=False)
  
  --> 767                 writer.grab_frame(**savefig_kwargs)
  
      768 
  
      769         # Reconnect signal for first draw if necessary
  
  
  
  C:\Users\Yahveh\AppData\Local\Enthought\Canopy\User\lib\site-packages\matplotlib\animation.pyc in grab_frame(self, **savefig_kwargs)
  
      225             verbose.report('MovieWriter -- Error '
  
      226                            'running proc:\n%s\n%s' % (out,
  
  --> 227                                                       err), level='helpful')
  
      228             raise
  
      229 
  
  
  
  UnicodeDecodeError: 'ascii' codec can't decode byte 0xa0 in position 3: ordinal not in range(128) 
  
  </module>

  Stared at them for a while.

  Thanks for your time !

  UPDATE : I followed the steps in this post for granting access to both C :\ffmpeg and destination folder, but no luck :(