The IPFS 480 is the re-encoded video, which seems to stream a bit faster than the original file. But this encoding is only available for videos that are 20 minutes or less.
It seems that you'll likely run into less problems with smaller file sizes than with larger ones with DTube.
The issues with DTube have been so bad though lately, not sure when they will fix these problems.
I uploaded a new video to youtube today and just stuck with doing a new blog post for it on Steemit.
Its too bad we're having issues too, because DTube is a such a great concept, I really want to see it work.