A method for encoding a video comprising: - encoding a picture of said video into a bitstream, the picture comprising at least two regions; - encoding a Supplemental Enhancement Information nesting message, wherein encoding said Supplemental Enhancement Information nesting message comprises: - encoding a parameter indicating a number of regions in said picture; - encoding, for each of said regions, a left offset defined from the left border of the picture, a right offset defined from the right border of the picture, a top offset defined from the top border of the picture and a bottom offset defined from the bottom border of the picture, the offsets defining the coordinates of said region; - encoding a parameter indicating a number of Supplemental Enhancement Information messages nested in said Supplemental Enhancement Information nesting message; - encoding, for each Supplemental Enhancement Information message nested in said Supplemental Enhancement Information nesting message, post-processing region-based information; - encoding information representative of an association of at least one region with at least one Supplemental Enhancement Information message nested in said at least one Supplemental Enhancement Information nesting message. - encoding a picture of said video into a bitstream, the picture comprising at least two regions; - encoding a Supplemental Enhancement Information nesting message, wherein encoding said Supplemental Enhancement Information nesting message comprises: - encoding a parameter indicating a number of regions in said picture; - encoding, for each of said regions, a left offset defined from the left border of the picture, a right offset defined from the right border of the picture, a top offset defined from the top border of the picture and a bottom offset defined from the bottom border of the picture, the offsets defining the coordinates of said region; - encoding a parameter indicating a number of Supplemental Enhancement Information messages nested in said Supplemental Enhancement Information nesting message; - encoding, for each Supplemental Enhancement Information message nested in said Supplemental Enhancement Information nesting message, post-processing region-based information; - encoding information representative of an association of at least one region with at least one Supplemental Enhancement Information message nested in said at least one Supplemental Enhancement Information nesting message. - encoding a parameter indicating a number of regions in said picture; - encoding, for each of said regions, a left offset defined from the left border of the picture, a right offset defined from the right border of the picture, a top offset defined from the top border of the picture and a bottom offset defined from the bottom border of the picture, the offsets defining the coordinates of said region; - encoding a parameter indicating a number of Supplemental Enhancement Information messages nested in said Supplemental Enhancement Information nesting message; - encoding, for each Supplemental Enhancement Information message nested in said Supplemental Enhancement Information nesting message, post-processing region-based information; - encoding information representative of an association of at least one region with at least one Supplemental Enhancement Information message nested in said at least one Supplemental Enhancement Information nesting message.