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, wherein each filter in the set of filters comprises a set of filter coefficients; 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 a first indication that indicates that a first LCU is to be filtered using a first filter, wherein the first LCU is in a first sub-group of LCUs, wherein the first 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 first LCU using the filter for the first LCU; receiving a second indication that indicates that a second LCU is to be filtered using a second filter, wherein the second LCU is in the first sub-group of LCUs, wherein the second filter is a filter other than the filter assigned to the first sub-group of LCUs; and filtering one or more CUs of the second LCU using the second filter.