Video encoders and video decoders filter reconstructed video data in a video encoding and/or video decoding processes and, more particularly, may perform adaptive loop filtering. Instead of implementing region adaptive (RA) classification using a fixed set of regions, a variable number of regions in a picture can be used. Additionally or alternatively, a global set of filters can be signaled in a parameter set from an encoder to a decoder, but instead of selecting filters from the global set based on an RA classification or a block adaptive (BA) classification, a filter from the global set can be explicitly signaled, for a given block, using a filter ID associated with the filter.