Patent ID: 7454076

Claim:
A method for processing an ordered series of digital signals that each have an amplitude from a finite set of amplitudes consisting of the most-likely-to-occur amplitude and at least one other amplitude, the processing to reduce the amount of data used to represent the digital signals and to form codewords such that the more likely to occur sequences of values of digital signals are represented by relatively short codewords and the less likely to occur sequences of values of digital signals are represented by relatively long codewords, the method comprising: for each run of consecutive signals of value or values other than the most-likely-to-occur value occurring in a first contiguous region defined by a breakpoint along the ordering of the series, encoding the runlength of the consecutive signals using a first runlength coding method, and forming a codeword that encodes the runlength using the first runlength coding method and further encodes the amplitudes and signs of each signals in the run, the breakpoint defining the first continuous region and a second contiguous region following the first contiguous region; for each run of consecutive signals of the most-likely-to-occur value occurring in the first region defined by the breakpoint, encoding the runlength of the consecutive signals of the most-likely-to-occur value using a second runlength coding method; and encoding the signals occurring in the second region defined by the breakpoint, the encoding using a second-region coding method, the second-region coding method including identifying events that include runs of consecutive signals of the most-likely-to-occur value in the second region and encoding said identified events in the second region using a third coding method, wherein the first, second, and third coding methods include variable length codes such that relatively short codewords are formed to represent sequences of values that are relatively more likely to occur, and relatively long codewords are formed to represent sequences of values that are relatively less likely to occur, and wherein the breakpoint value is selected from a finite set of pre-defined breakpoint values according to which of the breakpoints of the set produces the shortest number of bits, or the breakpoint defines a soft boundary between the first and second regions, such that for a block having a sequence of consecutive values all having the most-likely-to-occur value or all having other than the most-likely-to-occur value crosses the breakpoint, the boundary between the first and second region is at or after the end of the sequence such that the whole sequence or any event that starts in the first region is in the first region.