Patent ID: 7209056

Claim:
A lossless coding method for a signal in a floating-point format, comprising: (a) a step of converting a first signal sample sequence in the floating-point format into a second signal sample sequence in an integer format; (b) a step of losslessly compressing said second signal sample sequence in the integer format to produce a first code sequence; (c) a step of producing a difference signal in the floating-point format that corresponds to the difference between said second signal sample sequence in the integer format and said first signal sample sequence in the floating-point format; (d) a step of determining which coding processing is of higher compression efficiency, a first coding processing that codes a range of bits capable of assuming non-zero in a sample of said difference signal in the floating-point format, the range of bits being determined by the bit position of the most significant “1” in the corresponding sample in said second signal sample sequence in the integer format, or a second coding processing that directly codes said difference signal; and (e) a step of coding said difference signal by said first coding processing to produce a second code sequence if the result of said determination indicates said first coding processing, or coding said difference signal by said second coding processing to produce a second code sequence if the result of said determination indicates said second coding processing.