The video isnt on the blockchain, what is on the blockchain is a reference to the video which is hosted in the IPFS network.
Im going to set up an old PC as IPFS node this week.
In the following video, they show how you add something to the IPFS network (in this case meant to avoid dealing with the slow dtube uploader):

To do that, you have to run the IPFS daemon in the first place. If you keep that PC and the IPFS daemon running, you can then in a command prompt seperate to that in which you run ipfs daemon while its running (and it needs to keep running as long as you want to share it) "ipfs pin add (hash of your file)" and "ipfs dht provide (hash)" for each file you want to keep sharing via your node.
Other IPFS nodes buffer and distribute it, so your internet connection isnt as much as a bottleneck as one might think.

There is also talk of a cryptocurrency called filecoin related to hosting files, im interested but dont yet know much about it.