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• FFMPEG and Matplotlib for animations - strange outputs ?

  27 juin 2020, par user13132640

  I'm trying to create animations using FFMPEG and matplotlib. Using the below code, I am creating the FFMpeg writer, and then using a loop, writing a series of graphs to the animation. However, the outputs I'm getting are very strange ; sometimes, when I watch the .mp4 file, the first 5 seconds are blank, then the video "ends" (the playback time on my media player says that it's complete), and at that point, my animation shows up. Other times, some frames are missing or skipped. I've tried searching around, but frankly I haven't found anyone with similar issues.

  


  I just installed the latest version of FFMpeg today.

  


  FFMpegWriter = manimation.writers['ffmpeg']
metadata = dict(title='Animation test', artist='name')
writer = FFMpegWriter(fps=1, metadata=metadata) # 1 frames per second, each year is 1 second


  


  Then, the plotting part...(I've excluded the code where I setup the fig, ax etc.)

  


  with writer.saving(fig, "animation.mp4", dpi=200):
    year = "2005"
    for i in range(4):

        d1_plot = d1[d1['Year'].str.contains(year, na=False)]
        ax.scatter(d1_plot["Lat"], d1_plot["Long"], c='g', s=d1_plot["Size"], transform=ccrs.PlateCarree())
        ax.set_title(year)
        writer.grab_frame()
        year = str(int(year)+1)


  


• Python FuncAnimation is saved only 30%

  4 mars 2017, par cvut

  I am trying to make a movie out of data I’ve calculated. I am using ffmpeg writer. When I start the animation in Spyder it is working fine and goes to the end, but when I try to save it it goes only for first 30% of animation. How can I make it to save the whole animation ?

  Here is a bit of code( it’s long) ; MM is place where the matrices are stored (1200 of them).

  import matplotlib
  
  matplotlib.use("Agg")
  
  from mpl_toolkits.mplot3d import axes3d
  
  import matplotlib.animation as animation
  
  import numpy as np
  
  import matplotlib.pyplot as plt
  
  import matplotlib.cm as cm
  
  nx = 10
  
  ny = 10
  
  X=np.linspace(0, Lx, nx)
  
  Y=np.linspace(0, Ly, ny)   
  
  Writer = animation.writers['ffmpeg']
  
  writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1)
  
  
  
  plt.ion()
  
  fig = plt.figure()
  
  im = plt.contourf(X, Y, MM[0], np.linspace(T_ok,np.max(MM[-1]),150), cmap =     cm.hot)
  
  ax = fig.add_subplot(111, projection='3d')  
  
  plt.colorbar(im)
  
  
  
  def anime(i):
  
      ax.cla()
  
      im = ax.contourf(X, Y, MM[i], np.linspace(T_ok,np.max(MM[-1]),150), cmap = cm.hot)
  
      plt.title('%5.3f'%i)
  
      return im,
  
  
  
  anim = animation.FuncAnimation(fig, anime)
  
  anim.save('anime.mp4', writer=writer)

  EDIT : I just set frames to 10000 and it’s working, but I would like to know why. There are 1200 matrices that should be plotted.

• Python FuncAnimation is saved only 30%

  14 mars 2018, par cvut

  I am trying to make a movie out of data I’ve calculated. I am using ffmpeg writer. When I start the animation in Spyder it is working fine and goes to the end, but when I try to save it it goes only for first 30% of animation. How can I make it to save the whole animation ?

  Here is a bit of code( it’s long) ; MM is place where the matrices are stored (1200 of them).

  import matplotlib
  
  matplotlib.use("Agg")
  
  from mpl_toolkits.mplot3d import axes3d
  
  import matplotlib.animation as animation
  
  import numpy as np
  
  import matplotlib.pyplot as plt
  
  import matplotlib.cm as cm
  
  nx = 10
  
  ny = 10
  
  X=np.linspace(0, Lx, nx)
  
  Y=np.linspace(0, Ly, ny)   
  
  Writer = animation.writers['ffmpeg']
  
  writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1)
  
  
  
  plt.ion()
  
  fig = plt.figure()
  
  im = plt.contourf(X, Y, MM[0], np.linspace(T_ok,np.max(MM[-1]),150), cmap =     cm.hot)
  
  ax = fig.add_subplot(111, projection='3d')  
  
  plt.colorbar(im)
  
  
  
  def anime(i):
  
      ax.cla()
  
      im = ax.contourf(X, Y, MM[i], np.linspace(T_ok,np.max(MM[-1]),150), cmap = cm.hot)
  
      plt.title('%5.3f'%i)
  
      return im,
  
  
  
  anim = animation.FuncAnimation(fig, anime)
  
  anim.save('anime.mp4', writer=writer)

  EDIT : I just set frames to 10000 and it’s working, but I would like to know why. There are 1200 matrices that should be plotted.