To just watch video, and to do some capturing, there's the Apple Video Player software, which was included I believe with system 7.5 and later, it's definitely on a few 8.1 CDs I've got.
If you can track down a copy, Adobe Premiere 3 is also a fantastic piece of software to own, both to look at the history of desktop digital nonlinear editing, and because it's just about perfect for a stock or near-stock 840av, in terms of functionality, 1990s price level, and age.
Avid software does exist, however much of it would have required that you cram thousands worth of add-on cards into the machine, so avid setups were mainly maintained by studios at that time, at least intil Avid Cinema came along, I don't know if that was strictly a PowerPC thing, however.
If you can track down a copy, Adobe Premiere 3 is also a fantastic piece of software to own, both to look at the history of desktop digital nonlinear editing, and because it's just about perfect for a stock or near-stock 840av, in terms of functionality, 1990s price level, and age.
Avid software does exist, however much of it would have required that you cram thousands worth of add-on cards into the machine, so avid setups were mainly maintained by studios at that time, at least intil Avid Cinema came along, I don't know if that was strictly a PowerPC thing, however.