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• Saving Animated Matplotlib Chart to GIF

  29 mai 2020, par Jonathan Bechtel

  I have an animated matplotlib chart that I'm trying to save to a .gif file, but I can't get my image writer to work.

  



  I've installed imagemagick and verified that it works on my computer via the instructions given on its installation page, but when I do this :

  



  anim.save('gd.gif', writer='imagemagick')


  



  I get the following error message :

  



  MovieWriter imagemagick unavailable. Trying to use pillow instead.


  



  However, doing anim.save('gd.gif', writer='pillow') gives the following error message :

  



  ValueError: not enough image data


  



  I tried installing ffmpeg with the command conda install -c conda-forge ffmpeg. It looked like it installed correctly, but I don't know how to bind it to matplotlib apparently.

  



  Specifying the writer as ffmpeg gives the same error message that I encountered with imagemagick.

  



  I also tried adding imagemagick's path to matplotlib's config file path with the following line :

  



  animation.convert_path: 'C:\Program Files\ImageMagick-7.0.8-Q16\magick.exe'


  



  That was suggested in this question.

  



  None of these seemed to have worked though.

  



  I'm on Windows 10, and am using Python 3.7

  


• Advice on how to specify length of animated GPX video with ffmpeg/image2pipe

  21 mai 2019, par Chris Olin

  I’m working on a personal project involving an action camera that records GPS data alongside video from an image sensor. I found an open source projected on GitHub called ’trackanimation’ that uses a colored marker to trace the GPX path on a OpenStreetMaps overlay, but it appears that the project has been abandoned. I’m trying to sync the trackanimation video to the image sensor video, but when I try using video editing software to slow the GPX video down to 1%, it still ends up being shorter than the image sensor video. I’ve tried messing with the baked in ffmpeg command in make_video(), but still can’t get the output video to be as long as I want it to be.

  I started digging into the library source to see how the video was being created, tried tweaking a couple things to no avail.

  import trackanimation
  
  from trackanimation.animation import AnimationTrack
  
  
  
  gpx_file = "Videos/20190516 unity ride #2.mp4.gpx"
  
  gpx_track = trackanimation.read_track(gpx_file)
  
  
  
  fig = AnimationTrack(df_points=gpx_track, dpi=300, bg_map=True, map_transparency=0.7)
  
  fig.make_video(output_file="Videos/1-11trackanimationtest.mp4", framerate=30, linewidth=1.0)

      def make_video(self, linewidth=0.5, output_file='video', framerate=5):
  
          cmdstring = ('ffmpeg',
  
                       '-y',
  
                       '-loglevel', 'quiet',
  
                       '-framerate', str(framerate),
  
                       '-f', 'image2pipe',
  
                       '-i', 'pipe:',
  
                       '-r', '25',
  
                       '-s', '1920x1080',
  
                       '-pix_fmt', 'yuv420p',
  
                       output_file + '.mp4'
  
                       )

  I expect that I should be able to linearly "slow" the GPX video to a dynamic value based on the length of the video and the length I want it to be.

• How to plot an animated graph

  2 août 2019, par Mukonza Sabastian Simbarashe

  Following along How to Create Animated Graphs in Python when constructing an animated plot then on writing the ffmpeg I get the following error :

  'Requested MovieWriter ({}) not available'.format(name))
  
  RuntimeError: Requested MovieWriter (ffmpeg) not available

  After getting this error, I initially tried to install ffmpeg using pip by the following method :

  python -m install ffmpeg

  and it seems to have successfully installed ffmpeg, but going back to my code I still get the same error

  Find below my code :

  import numpy as np
  
  import pandas as pd
  
  import seaborn as sns
  
  import matplotlib
  
  import matplotlib.pyplot as plt
  
  import matplotlib.animation as animation
  
  
  
  overdoses = pd.read_excel(r'C:\Users\ACER\Desktop\overdose_data_1999-2015.xls',sheet_name='Online',skiprows =6)
  
  
  
  def get_data(table,rownum,title):
  
      data = pd.DataFrame(table.loc[rownum][2:]).astype(float)
  
      data.columns = {title}
  
      return data
  
  
  
  title = 'Heroin Overdoses'
  
  d = get_data(overdoses,18,title)
  
  x = np.array(d.index)
  
  y = np.array(d['Heroin Overdoses'])
  
  overdose = pd.DataFrame(y,x)
  
  overdose.columns = {title}
  
  Writer = animation.writers['ffmpeg']

  Here is the stack trace :

  Traceback (most recent call last):
  
    File "C:\Python\Python36\lib\site-packages\matplotlib\animation.py", line 161, in __getitem__
  
      return self.avail[name]
  
  KeyError: 'ffmpeg'
  
  
  
  During handling of the above exception, another exception occurred:
  
  
  
  Traceback (most recent call last):
  
    File "", line 1, in <module>
  
      Writer = animation.writers['ffmpeg']
  
    File "C:\Python\Python36\lib\site-packages\matplotlib\animation.py", line 164, in __getitem__
  
      'Requested MovieWriter ({}) not available'.format(name))
  
  RuntimeError: Requested MovieWriter (ffmpeg) not available
  
  </module>