Recently I required edited videos with a specific bitrate. I supplied the video editor with a relevant ffmpeg command to convert his work into the format I need. He asked me how he could batch convert them, and I, a *nix user, was momentarily stumped. Then based on this tutorial, I created a one line batch script that will convert all files of a given type in the current directory:
FOR %%i IN (*.avi) DO ffmpeg -i %%i ... rest of command ... %%i.mpg
I hope this helps someone random on the interwebs!