Python Matplotlib Basemap animation with FFMpegwriter stops after 820 Frames?

Question

If I run the following code it just stops after 820 Frames. I tested this on both a Ubuntu 12.04 VM and on Linux Mint 15. Unfortunately there is no error message. The program just hangs after printing 2012-06-02T16:54:00

import os, sys
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap
import matplotlib.animation as animation
from datetime import datetime,timedelta

def animation_test(start,end,fps=10,save_path='/home/username/animation_test/',\
save_name="test.mp4",dpi=80):

    step = timedelta(minutes = 3)

    current = start

    dates =[]

    frame = 0

    while current <=end:
        dates.append(current)
        current += step

    fig = plt.figure(figsize=(16,9),facecolor='k',edgecolor='k')
    ax = fig.add_subplot(111)

    metadata = dict(title='Movie Test', artist='Matplotlib',
            comment='Movie support!')
    writer = animation.FFMpegWriter(fps=fps, metadata=metadata,bitrate=20000)

    direction = -0.5
    lat_current = 0
    lon_current = 0

    with writer.saving(fig,os.path.join(save_path,save_name),dpi):

        for current in dates:

            ax.cla()
            if direction > 0 and lat_current > 40 or \
                   direction < 0 and lat_current < -40:
                    direction = - direction

            lat_current = lat_current + direction
            lon_current = lon_current - 0.75
            if lon_current < -180 :
                lon_current += 360
            basem = Basemap(projection='ortho', lat_0=lat_current, lon_0=lon_current, resolution='l',ax=ax)
            basem.drawcoastlines()

            #plt.show()

            plt.savefig(os.path.join(save_path, 'frame%d.png'%frame),
                dpi=dpi,facecolor='w',edgecolor='k')

            writer.grab_frame()
            frame += 1
            print current.isoformat()

start = datetime.now()
animation_test(datetime(2012,6,1,0,0,0),datetime(2012,6,4,0,0,0),fps=10,dpi=80)
print datetime.now() - start

To explain the code a little bit: I want to make an animation of satellite data which comes in small 3 minute files and show it on a rotating globe. This is why I chose to make the loop in the following example code step through the animation in 3 minute steps. I just removed the reading and plotting of the satellite data in order to make the code executable by anyone.

When I removed basemap from the program and just plotted a scatterplot of random data the program ran all the way through.

I'm not sure but I don't think that it is a memory issue since my RAM is only utilized approx. 20% while the program is running.

Thanks for any help in getting to the bottom of this.

Answer 1

After I installed FFMPEG version 0.10.7 from https://launchpad.net/~jon-severinsson/+archive/ffmpeg it works.

So it seems that this might be an issue with libav which is used by ubuntu by default.