Sous-vide (/suːˈviːd/; French for "under vacuum") is a method of cooking in which food is vacuum-sealed in a plastic pouch and then placed in a water bath or steam environment for longer than normal cooking times (usually 1 to 7 hours, up to 48 or more in some cases) at an accurately regulated temperature much lower than normally used for cooking (typically around 55 to 60 °C (131 to 140 °F) for meat, higher for vegetables). The intent is to cook the item evenly, ensuring that the inside is properly cooked without overcooking the outside, and to retain moisture.
First of all, good video...but you should only use sou vide on better quality beef i.e prime dry-aged...and I would trim that fat slightly on the rim just before searing and use it as flavoring in the pan or save it for gravy..