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• How can we add Animation on touch position overlay on video in android

  11 août 2017, par Vinesh Chauhan

  I am looking for any command of ffmpeg or any other library by using it I can archive an application that can able to do animation on capture video from the android device.

  I have already gone through some tutorials about this topic but I didn’t find any help related to this.

  please help !. TIA.

• Can't save matplotlib animation (ffmpeg)

  25 mai 2014, par renger

  I am trying to get a simple animation saved using ffmpeg. I followed a tutorial to install ffmpeg, and I can now access it from the command prompt.

  Now I run this piece of code :

  import numpy as np
  
  from matplotlib import pyplot as plt
  
  from matplotlib import animation
  
  
  
  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)
  
  
  
  mywriter = animation.FFMpegWriter()
  
  anim.save('mymovie.mp4',writer=mywriter)
  
  
  
  plt.show()

  I get this error :

  Traceback (most recent call last):
  
    File "<stdin>", line 1, in <module>
  
     File "C:\Python27\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 523, in runfile
  
      execfile(filename, namespace)
  
    File "C:\Users\Renger\.xy\startups\b.py", line 23, in <module>
  
      anim.save('mymovie.mp4',writer=mywriter)
  
    File "C:\Python27\lib\site-packages\matplotlib\animation.py", line 609, in save
  
      with writer.saving(self._fig, filename, dpi):
  
    File "C:\Python27\lib\contextlib.py", line 17, in __enter__
  
      return self.gen.next()
  
    File "C:\Python27\lib\site-packages\matplotlib\animation.py", line 166, in saving
  
      self.setup(*args)
  
    File "C:\Python27\lib\site-packages\matplotlib\animation.py", line 156, in setup
  
      self._run()
  
    File "C:\Python27\lib\site-packages\matplotlib\animation.py", line 183, in _run
  
      stdin=subprocess.PIPE)
  
    File "C:\Python27\lib\subprocess.py", line 711, in __init__
  
      errread, errwrite)
  
    File "C:\Python27\lib\subprocess.py", line 948, in _execute_child
  
      startupinfo)
  
  WindowsError: [Error 2] Het systeem kan het opgegeven bestand niet vinden
  
  </module></module></stdin>

  The last dutch sentence does mean something like : The system can’t find the specified file.

  What do these errors mean, and how can I solve them ?

  Best,

• Why does ffmpeg could only record the first 100 frames of the animation ?

  9 février 2020, par jack fang

  I am using the following Python code to make an animation and want to save it as a video through FFmpeg (in PyCharm) :

  import numpy as np
  
  import matplotlib.pyplot as plt
  
  import matplotlib.animation as animation
  
  from matplotlib.animation import FFMpegWriter
  
  
  
  def func():
  
      for j in range(1, len(t)):
  
          time = j * 0.01
  
          print('time:{:2}'.format(time))
  
          yield time
  
  
  
  def animate(data):
  
      time = data
  
      ax2.plot(time, time, **{'marker':'o'})
  
      ax2.set_title('t = {:.2}'.format(time))
  
      return  ax2
  
  
  
  def init():
  
      ax2.plot(0, 0)
  
      return ax2
  
  
  
  dt = 0.01
  
  t = np.arange(0, 50, dt)
  
  
  
  fig2 = plt.figure()
  
  ax2 = fig2.add_subplot(111, autoscale_on=True)
  
  ax2.grid()
  
  
  
  ani = animation.FuncAnimation(fig2, animate, func, interval=dt*1000, blit=False, init_func=init, repeat=False)
  
  
  
  plt.rcParams['animation.ffmpeg_path'] = 'C:\Program Files\\ffmpeg\\bin\\ffmpeg.exe'
  
  writer = FFMpegWriter(fps=15, metadata=dict(artist='Me'), bitrate=1800)
  
  ani.save("movie.mp4", writer=writer)
  
  
  
  #plt.show()

  But when time reaches 1.0, the process stopped but it is supposed to stop when time reaches 50.0. The following picture shows when the process stopped. The PyCharm Run console
  I then check movie.mp4 and find that the video ends when time reaches 1.0.
  That is to say, only the first 100 frames of the animation were converted into the .mp4 file, so I was very confused where did the rest of the frames went ?

  I tried to run the code through windows cmd but got the same result.
  I then uncomment the line #plt.show() and found that the process stopped when time reaches 50.0 and the animation could be displayed properly but still only the first 100 frames was converted.

  I am now very confused about this problem and don’t know how to solve it. Appreciated for your help. :)