matplotlib-devel Mailing List for matplotlib

I'm having a tough time figuring this out: Saving an animation seems to
hang when using `streamplot`. The exact same animation runs without issue
when calling show.
On my system, the example below hangs consistently at frame 173. However,
the number of saved frames (before hanging) varies with density of stream
lines (i.e. number of line segments in streamplot): More frames saved for
lower density.
Seems to be a memory or file-size issue, but
 * Memory use doesn't seem to grow. (this suggests that ffmpeg adds
frames to disk as opposed to memory.)
 * Saving the animation up to the frame just before it hangs gives modest
(~1MB) videos.
Maybe this is a limitation of `ffmpeg`?
Can someone confirm that the example hangs on their system? (Somehow, I
often run into bugs that are not reproducible.)
In case this is system dependent:
* OSX 10.6
* Python 2.6.1 (system install)
* matplotlib master
* ffmpeg 0.10
Simple plots seem to work fine, but I should probably try to reproduce
using something other than streamplot (maybe create the equivalent number
of line and arrow collections).
-Tony
#~~~ Example
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
fig, ax = plt.subplots()
# do nothing function that prints frame
def update(frame_num):
 print frame_num
 return []
Y, X = np.mgrid[:1:100j, :1:100j]
U = np.ones_like(X)
V = np.ones_like(X)
ax.streamplot(X, Y, U, V, density=1)
ani = animation.FuncAnimation(fig, update, save_count=500)
# save hangs at frame 173 (this probably varies by system, if it's
reproducible).
ani.save('animation.avi')
# show animates all frames w/o issue.
#plt.show()