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• Saving animations using ffmpeg and matplotlib

  2 juillet 2015, par PedroLago

  im new in here and new in python, im doing some animations with animation.FuncAnimation of matplotliib. The animation works perfectly but i´m having problems saving the animations. here is the part of the code of the animation.

  import numpy as np 
  
  import matplotlib.pyplot as plt
  
  import matplotlib.animation as animation
  
  
  
  fig, ax = plt.subplots()
  
  
  
  line,  = ax.plot(range(N),sin(x[0,:]),'o-')
  
  ax.axis([0,1,-1,1])
  
  
  
  def animate(i):
  
      line.set_ydata(sin(x[i,:]))  # update the data
  
      return line,
  
  
  
  def init():
  
      line.set_ydata(np.ma.array(x[0,:], mask=True))
  
      return line,
  
  
  
  ani = animation.FuncAnimation(fig, animate, np.arange(1, 10000),
  
      interval=25, init_func=init, blit=True)
  
  ani.save('2osc.mp4', writer="ffmpeg")
  
  plt.show()

  where x[ :, :] is previously set. ani.save is saving every frame of the animation as a .npg image instade of saving the movie. I dont know if this is how it is suposed to work and i have to do the movie with the .npg with another program or if im doing something wrong.
  Obs : i’ve previously installed ffmpeg and it seems to be working just fine.

• avcodec/pngdec : Copy IHDR & plte state from last thread

  29 juin 2015, par Michael Niedermayer

  avcodec/pngdec : Copy IHDR & plte state from last thread
  Previously these chunks where parsed again for each frame with threads
  
  but not without leading to a different path and the potential for
  
  inconsistencies
  This also removes a related special case from decode_ihdr_chunk()
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] libavcodec/pngdec.c

• How do I simulate rtp (packet) loss simulation ?

  18 juin 2015, par Haroldy

  I previously used JM14.2 to see the cause and effect on the quality of yuv file by the number of slice, FMO, and etc. In the end, I want to increase robustness and resilience to YUV file.

  I encoded yuv file first, and then damage the 264 file with the provided simulation rtp_loss (JM14.2) with 5% loss of packets. and then I decoded the 264 file to see the result.

  Now I want to try similar simulation with ffmpeg. So I encoded video with this command

      ffmpeg -f rawvideo -s:v 352x288 -i akiyo.yuv -vcodec libx264 -preset slower -x264opts slice-max-size=150:bframes=1:keyint=20 -profile:v baseline -f rawvideo hi.264

  after I made hi.264 file, I tried to run rtp_loss (JM14.2) packet loss simulation, but I get an error.

  I wonder if there is ffmpeg command for rtp loss simulation. If there is, could you tell me how to use it ?
  Thanks