Podcasting and Vodcasting

My definition of podcasting is an audio file that can be downloaded and listened to by different people through the web. I think the difference between podcasting and vodcasting is that podcasting involves audio files while vodcasting incorporates images or videos. In my math classes I feel that podcasting would not be as beneficial as vodcasting. Many of the concepts taught in math would be difficult to learn through audio only. I think that vodcasting would help students if I was explaining concepts while demonstrating them visually. I would like to eventually incorportate vodcasts into my classroom website. One thing that I not completely sure of is whether there is a difference between video files and vodcasts.