The upload endpoints come with their own ipfs nodes, it's how the file gets added to the ipfs network.
You could put the file into ipfs via another method and then using the upload feature of DTube specify the hash, so if someone is willing to let you upload to their node then you can do things that way.
You could put the file into ipfs via another method and then using the upload feature of DTube specify the hash, so if someone is willing to let you upload to their node then you can do things that way.