A method of encoding video data, the method comprising: generating a filter syntax element for each filter of a first and a second set of filters, wherein a first value for the filter syntax element indicates that coefficients of a filter comprise at least one non-zero coefficient and a second value for the filter syntax element indicates the coefficients of a filter do not comprise at least one non-zero coefficient; in response to the filter syntax element being set to the first value, generating for inclusion in an encoded bitstream, the filter syntax element and additional information identifying the coefficients of the filter; and in response to the filter syntax element being set to the second value, generating for inclusion in the encoded bitstream, the filter syntax element without additional information identifying the coefficients of the filter, wherein the syntax element is a single bit, and wherein the syntax element is part of a header of a series of video blocks, applying a first filter from the first set of filters to a first input based on a value of a first activity metric to generate a first filtered result, wherein the first input comprises a post-deblocked reconstructed image, the value of the first activity metric being within a first range of values, wherein the first range of values for the first activity metric is indexed to the first filter and a different range of values for the first activity metric is indexed to a different filter of the first set of filters, applying a second filter from the second set of filters to a second input based on a second activity metric to generate a second filtered result, wherein the second input comprises one of a pre-deblocked image, a prediction image, and a quantized prediction error image, the value of the second activity metric being within a second range of values, wherein the second range of values for the second activity metric is indexed to the second filter and a different range of values for the second activity metric is indexed to a different filter of the second set of filters, wherein the second filter is different than the first filter, and wherein the first input and the second input correspond to intermediate video block data produced during a video coding process; wherein the first activity metric is an activity metric quantifying a pixel variance within a coded unit of the first input, and wherein the second activity metric is an activity metric quantifying a pixel variance within a coded unit of the second input; and generating a filtered image based on a combination of the first filtered result and the second filtered result. generating a filter syntax element for each filter of a first and a second set of filters, wherein a first value for the filter syntax element indicates that coefficients of a filter comprise at least one non-zero coefficient and a second value for the filter syntax element indicates the coefficients of a filter do not comprise at least one non-zero coefficient; in response to the filter syntax element being set to the first value, generating for inclusion in an encoded bitstream, the filter syntax element and additional information identifying the coefficients of the filter; and in response to the filter syntax element being set to the second value, generating for inclusion in the encoded bitstream, the filter syntax element without additional information identifying the coefficients of the filter, wherein the syntax element is a single bit, and wherein the syntax element is part of a header of a series of video blocks, applying a first filter from the first set of filters to a first input based on a value of a first activity metric to generate a first filtered result, wherein the first input comprises a post-deblocked reconstructed image, the value of the first activity metric being within a first range of values, wherein the first range of values for the first activity metric is indexed to the first filter and a different range of values for the first activity metric is indexed to a different filter of the first set of filters, applying a second filter from the second set of filters to a second input based on a second activity metric to generate a second filtered result, wherein the second input comprises one of a pre-deblocked image, a prediction image, and a quantized prediction error image, the value of the second activity metric being within a second range of values, wherein the second range of values for the second activity metric is indexed to the second filter and a different range of values for the second activity metric is indexed to a different filter of the second set of filters, wherein the second filter is different than the first filter, and wherein the first input and the second input correspond to intermediate video block data produced during a video coding process; wherein the first activity metric is an activity metric quantifying a pixel variance within a coded unit of the first input, and wherein the second activity metric is an activity metric quantifying a pixel variance within a coded unit of the second input; and generating a filtered image based on a combination of the first filtered result and the second filtered result.