Patent ID: 7281033

Claim:
A method of forming a reduced compressed digital signal according to a hierarchical compression format, the reduced compressed digital signal being formed from an initial compressed digital signal with several hierarchical levels which has been obtained by the compression, according to the hierarchical compression format, of a digital signal comprising data representing physical quantities, the initial signal thus comprising at least one header which comprises information representing a configuration of the signal and the structure of the data therein, the configuration of the signal being defined by an initial set of parameters characterizing all the hierarchical levels of the signal, said method comprising the following steps: forming, from the at least one header of the initial compressed signal, at least one header of the reduced compressed signal which comprises information representing a reduced configuration of the initial signal and the structure of the data in the compressed signal of reduced configuration, the reduced configuration being defined by a final set of parameters characterizing at least one of the hierarchical levels of the initial compressed signal; extracting the compressed data corresponding to the final set of parameters from the initial compressed signal; and inserting the extracted data into the reduced compressed signal being formed.