There were a few versions of VirtualDub that open VOBs and AC3. Most were from the 1.4.X area. In my opinion it was more complicated to use virtualdub to mess with AC3 and VOBs. I found it much easier to use a ripping packge. It's all on you. Actually, Divx has gotten MUCH easier to use. I haven't encoded a movie in a while but 2-3 years ago I was ripping movies daily and experimenting with several programs.