[Tutor] Allow only one instance of a process

[Kent Johnson]

On Sat, May 16, 2009 at 10:26 PM, Sylvain Ste-Marie
<stemarie.sylvain at gmail.com> wrote:
> I'm currently writing a script to batch convert video for my psp
>
> It basically looks into a folder for video and launch ffmpeg:
>
> ffmpeg -i "videoname" -f psp -r 29.97 -b 768k -ar 24000 -ab 64k -s 368x208
> "videoname.mp4"
>
> my idea is basically to check for pid but how do i do that?

Look at psutil:
http://code.google.com/p/psutil/

But you will have a race condition if you do something like this:

if ffmpeg is not running:
  start ffmpeg

A file lock is a better solution. Google 'python file lock' for recipes.

Kent