Hi shane,
Welcome to the Mattress Forum! 
Videos of a product are not reliable methods to show firmness. While “firmness” is subjective, the best way to relate this would be to know the componentry inside of the mattress as a starting point, and if possible the ILDs of those layers, which can then give you a general idea within a particular lineup of how one model might compare to another. Brooklyn Bedding is very forth coming with this information, both on their web site and here on the forum. They even have a scale relating one product to another within the Best Mattress Ever line, with general guidelines of sleeping styles for which each model is most commonly appropriate.
Overall there are no “standard” definitions or consensus of opinions for firmness ratings and different manufacturers can rate their mattresses very differently than others so a mattress that one manufacturer rates as being a specific firmness could be rated very differently by another manufacturer. Different people can also have very different perceptions of firmness and softness compared to others as well and a mattress that feels firm for one person can feel like “medium” for someone else or even “soft” for someone else (or vice versa) depending on their body type, sleeping style, physiology, their frame of reference based on what they are used to, and their individual sensitivity and perceptions. There are also different types of firmness and softness that different people may be sensitive to that can affect how they “rate” a mattress as well (see post #15 here) so different people can also have very different opinions on how two mattresses compare in terms of firmness and some people may rate one mattress as being firmer than another and someone else may rate them the other way around. This is one of the reasons I always suggest that you place a phone call directly with the manufacturer before placing an order for an item like this, as they will have the best knowledge about their products and best be able to relate which particular item in their lineup that the feel will give you the best chance at success.
Phoenix