Actually, viDrop recognizes VOB files. If you open windows explorer and then drag & drop the vob file to the green "Input A/V file" field in viDrop, it will recognize it.
The problem is that I forgot to add .vob file extension in the "Select input A/V file" dialog.....
This will be fixed in the next version.
:EDIT
If somebody wonders why the program is called "viDrop": it's short for "video drop" - because you drag&drop videos onto it
It has nothing to do with the linux "vi" editor
