I think it's possible to add stuff like that without issues since you're adding the source in the description below.
I See this required indeed If we want Dtube to be a real alternative to youtube, we need to add different content type to attract more people on Dtube (Sport, TV, Movies, ...etc).

But It's all about copyright issues, you can mention the source of this video below and make edits on it and there will not be a problem.

This way works regularly with youtube, So I think it can work With Dtube too :)