The different format types can be a little hard to understand at first, so I will explain. 

The first version was called Video 8 or Standard 8. After that came Hi8 and then Digital 8. Most players are backwards compatible.

What does backwards compatible mean?

This means that something is capable of loading and playing earlier versions of the media. A Digital 8 player will play all 3 formats, a Hi8 player will play Hi8 and Video 8 and Video 8 players will only play video 8.