Mass convert videos to FLV format with watermarking in Windows

"The first thing that comes to mind is FFmpeg.

For watermarking, it is something like:

ffmpeg -i input.avi -vhook 'vhook/imlib2.so -x 0 -y 0 -i overlay.png' output.avi

Where overlay.png is the watermark.

What you basically want to do is to put this in your workthrough and run it on every file in the project, and it should do the job."