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• AttributeError while saving an animation using celluloid, Python 3.9

  26 juillet 2021, par rafael gf

  I'm trying to create a simple animation using the celluloid library, but I'm getting an attribute error when trying to save it. I'm not familiar with ffmpeg, but I read I should install it and point to its executable file for the saving to work, not sure what's going wrong. The massage I'm getting is :

  


  Exception has occurred: AttributeError&#xA;type object &#x27;FuncAnimation&#x27; has no attribute &#x27;_first_draw_id&#x27;&#xA; File "C:\Users\Fernando\Documents\Circulos\circulos.py", line 102, in <module>  anim.save(anim, filename="my_animation.gif", writer=FFwriter)&#xA;</module>

  


  I'll out the simplification version of the code below - I'm suppressing the part where I do some tucking with the circles, but I've done some testing plot by plot and it is working fine.

  


  import smtplib, os
import matplotlib.pyplot as plt
from matplotlib import animation
import math
from celluloid import Camera

plt.rcParams['animation.ffmpeg_path'] = os.getcwd() + '\\Circulos\\ffmpeg\\bin\\ffmpeg.exe'


#axes
figure, axes = plt.subplots()
axes.set_aspect(1)
axes.set_xlim((-xmax(C)),(xmax(C)))
axes.set_ylim((-ymax(C)),(ymax(C)))

b = 0

#add initial circles
for a in range 5:
    draw_circle = plt.Circle((a, a), 2, fc = 'None', ec = 'r')
    axes.add_artist(draw_circle)


#create figure and camera
figure, axes = plt.subplots()
axes.set_aspect(1)
axes.set_xlim((-xmax(C)),(xmax(C)))
axes.set_ylim((-ymax(C)),(ymax(C)))
camera = Camera(figure) 

Frame_time = 10

for b in range(Frame_time):

     #add circles
     for a in range 5:
        draw_circle = plt.Circle((a, a), 2, fc = 'None', ec = 'r')
        axes.add_artist(draw_circle)

    #Frame Picture
    camera.snap()


#create animation
anim = camera.animate()
anim = animation.FuncAnimation
FFwriter = animation.FFMpegWriter()
anim.save(anim, filename="my_animation.gif", writer=FFwriter)


  


  I'm working on VS code, the latest version I just updated it, and python 3.9

  


• Create endless loop animation using ffmpeg using only certain frames

  26 juillet 2021, par Rick T

  I can create an animated gif using the commands below.

  


  ffmpeg -i wrist_0001.png -vf palettegen=16 palette.png

ffmpeg -i wrist_%04d.png -i palette.png -filter_complex "fps=20,scale=720:-1:flags=lanczos[x];[x][1:v]paletteuse" logo.gif


  


  What I'm trying to know how to do is :

  


  

  1. Create another animated gif using just the first 20 frames and the animation loops endlessly (no pausing at the end of the animation).

  


  2. Create another animated gif using just the first 20 frames where the animation plays then pauses at the end for 3 seconds then continues. (endlessly) Example : (play animation - pause 3 seconds - play animation - pause 3 seconds - play animation - pause 3 seconds...)

  


  


  Note : I'm trying to avoid having to type in wrist_0001.png wrist_0002.png...is there away to do wrist_0001.png to wrist_0020.png ?

  


• matplotlib 3D linecollection animation gets slower over time

  15 juin 2021, par Vignesh Desmond

  I'm trying to animate a 3d line plot for attractors, using Line3DCollection. The animation is initally fast but it gets progressively slower over time. A minimal example of my code :

  


  def generate_video(nframes):

    fig = plt.figure(figsize=(16, 9), dpi=120)
    canvas_width, canvas_height = fig.canvas.get_width_height()
    ax = fig.add_axes([0, 0, 1, 1], projection='3d')

    X = np.random.random(nframes)
    Y = np.random.random(nframes)
    Z = np.random.random(nframes)

    cmap = plt.cm.get_cmap("hsv")
    line = Line3DCollection([], cmap=cmap)
    ax.add_collection3d(line)
    line.set_segments([])

    def update(frame):
        i = frame % len(vect.X)
        points = np.array([vect.X[:i], vect.Y[:i], vect.Z[:i]]).transpose().reshape(-1,1,3)
        segs = np.concatenate([points[:-1],points[1:]],axis=1)
        line.set_segments(segs)
        line.set_array(np.array(vect.Y)) # Color gradient
        ax.elev += 0.0001
        ax.azim += 0.1

    outf = 'test.mp4'
    cmdstring = ('ffmpeg', 
                    '-y', '-r', '60', # overwrite, 1fps
                    '-s', '%dx%d' % (canvas_width, canvas_height),
                    '-pix_fmt', 'argb',
                    '-f', 'rawvideo',  '-i', '-',
                    '-b:v', '5000k','-vcodec', 'mpeg4', outf)
    p = subprocess.Popen(cmdstring, stdin=subprocess.PIPE)

    for frame in range(nframes):
        update(frame)
        fig.canvas.draw()
        string = fig.canvas.tostring_argb()
        p.stdin.write(string)

    p.communicate()

generate_video(nframes=10000)


  


  I used the code from this answer to save the animation to mp4 using ffmpeg instead of anim.FuncAnimation as its much faster for me. But both methods get slower over time and I'm not sure how to make the animation not become slower. Any advice is welcome.

  


  Versions :
Matplotlib : 3.4.2
FFMpeg : 4.2.4-1ubuntu0.1