QuickTime Player can't open old "DV movie" clips

I recently revived an old PowerMac G4 (2002 model). While doing so I stumbled across some old home movies that I had imported in 2003 from a Hi8 analog camcorder. The movies consist of a large number of ~2gb clips that the Finder says are of type "DV movie". On the G4 running 10.4.11, QuickTime Player has no issue playing these movie clips. However, on my 2019 iMac running 14.6.1, when I try to open them I get the following error messages from QuickTime Player:

The document “Clip 01” could not be opened.

The file isn’t compatible with QuickTime Player.

I'm guessing they are in some outdated codec format that QuickTime Player no longer supports. The G4 version of QuickTime Player says the format is "DV".

I'm not certain how I originally created these movies. The camera only has analog outputs and the G4 has no analog inputs. I think I may have used some other piece of hardware to do the digital conversion. I have an old VHS -> DVD converter that I think does RCA analog input to digital output, so that's probably what I used, along with the G4's firewire input.

How do I fix QuickTime Player or fix these movie clips so they are playable with current versions of QuickTime Player?