1. A method for decoding video data, the method comprising: receiving, in a parameter set for a group of largest coding units (LCUs), information for constructing a set of filters for an adaptive loop filter (ALF) operation; receiving, in the parameter set, an indication of how to divide the group of LCUs into sub-groups of LCUs; assigning each of the sub-groups of LCUs to a filter from the set of filters; receiving an indication that indicates that a first LCU is to be filtered using the ALF operation, wherein the first LCU is in a first sub-group of LCUs; and determining a filter for the first LCU based on the indication that the first LCU is to be fileted by the ALF and based on the indication of how to divide the group of LCUs into the sub-group of LCUs, wherein the filter for the first LCU corresponds to a filter assigned to the first sub-group of LCUs; filtering one or more coded units (CUs) of the LCU using the filter for the first LCU.