Barra and Humaita are 2 neighborhoods from Rio de Janeiro, they are both runned by gracies, with the same technique tought by the family. Gracie Barra was founded after Carlos Gracie moved to that neighborhood.
After the years passed, Gracie Barra TEAM started to be more competition oriented.
They are pretty much the same technique-wise.
There are 50+ Gracie Family members involved with JJ worldwide, different techniques and methods of teching will eventually make one differ the other but IMO we didn't get to that point yet (besides NO GI training ofcourse).
Just know that when u refer to Gracie Barra, you are talking about a Team, not different from Nove União for example.
They all teach BJJ and all the BJJ came from the Gracies.