The Opalvision card was considered by many to be *the* video processing / video editing card until the release of the NewTek Video Toaster and Video Flyer.
The Opalvision had a large following in the early 1990s and the developer community for it was a small but active bunch. If you card came with the factory software, you are in good shape and should give the card a try. If all you have is the card, start searching the internet for software (ebay, etc...).
I think you will find that the Opalvision is a good card to experiment with but if you really want to do video editing on an Amiga, the only serious option is to use the NewTek cards mentioned above.
Good luck,
Lee Stanford