A video decoding apparatus, comprising: an entropy decoder configured to obtain video information including picture reconstruction information and offset information from a bitstream; a predictor configured to reconstruct a picture based on the picture reconstruction information; and a filter configured to apply an in-loop filter to the reconstructed picture, wherein the filter applies a deblocking filtering process to the reconstructed picture, and applies a sample adaptive offset process to the reconstructed picture based on the offset information after completing process of the deblocking filtering, wherein the offset information includes first offset information indicating whether the sample adaptive offset process is enabled and second offset information for applying an offset to a sample when the first offset information indicates that the sample adaptive offset process is enabled, wherein the second offset information includes offset type information for specifying an offset type for the sample, wherein the offset type information indicates that a band offset is applied to the sample, wherein the second offset information includes information on offset values for multiple bands, characterized in that the second offset information includes start band information explicitly indicating a variable start of the multiple bands to determine together with end band information indicating a variable end of the multiple bands a band group comprising the multiple bands among 32 bands, the start band information being different from the offset type information, wherein an offset value, corresponding to a band among the multiple bands is applied to the sample. an entropy decoder configured to obtain video information including picture reconstruction information and offset information from a bitstream; a predictor configured to reconstruct a picture based on the picture reconstruction information; and a filter configured to apply an in-loop filter to the reconstructed picture, wherein the filter applies a deblocking filtering process to the reconstructed picture, and applies a sample adaptive offset process to the reconstructed picture based on the offset information after completing process of the deblocking filtering, wherein the offset information includes first offset information indicating whether the sample adaptive offset process is enabled and second offset information for applying an offset to a sample when the first offset information indicates that the sample adaptive offset process is enabled, wherein the second offset information includes offset type information for specifying an offset type for the sample, wherein the offset type information indicates that a band offset is applied to the sample, wherein the second offset information includes information on offset values for multiple bands, characterized in that the second offset information includes start band information explicitly indicating a variable start of the multiple bands to determine together with end band information indicating a variable end of the multiple bands a band group comprising the multiple bands among 32 bands, the start band information being different from the offset type information, wherein an offset value, corresponding to a band among the multiple bands is applied to the sample.