ffmpeg never dies

[agalera]

I'm testing the bookstore and see never die ffmpeg that starts

from moviepy.editor import *
video = VideoFileClip("KYON8KR0UY8.mp4").subclip(50,60)

ps aux

root       339  0.0  0.0 257896 53484 ?        Tl   18:31   0:00 python3 /usr/bin/ipython3
root       346  0.0  0.0      0     0 ?        Z    18:31   0:00 [ffmpeg] <defunct>
root       366  0.0  0.0 387448 26384 ?        Tl   18:31   0:00 /usr/bin/ffmpeg -i KYON8KR0UY8.mp4 -vn -loglevel error -f s16le -acodec pcm_s16le -ar 44100 -ac 2 -
root       376  0.0  0.1 1066292 70312 ?       Tl   18:31   0:00 /usr/bin/ffmpeg -ss 49.000000 -i KYON8KR0UY8.mp4 -ss 1.000000 -loglevel error -f image2pipe -pix_fmt rgb24 -vcodec rawvideo -

I am doing something wrong? I have to indicate the end of the process?

Thank you!

[agalera]

rel: #164