Floating point type digital signal reversible encoding method, decoding method, devices for them, and programs for them
First Claim
1. A lossless coding method for a digital signal in a floating-point format, comprising:
- (a) a step of converting a first digital signal sample in the floating-point format into a second digital signal sample in an integer format;
(b) a step of losslessly compressing a sequence of said second digital signal samples in the integer format to produce a first code sequence;
(c) a step of producing a difference signal that corresponds to the difference between said second digital signal sample in the integer format and said first digital signal sample in the floating-point format; and
(d) a step of outputting said first code sequence and difference information corresponding to said difference signal as a coding result.
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Abstract
Digital signal samples X in a floating-point format, each of which is composed of 1 bit of sign, 8 bits of exponent E and 23 bits of mantissa M, are converted through rounding by an integer formatting part 12 into digital signal samples Y in an integer format, the sequence of the digital signal samples Y is losslessly compression-coded by a compressing part 13 into a code sequence Ca, and the code sequence Ca is output. The digital signal samples Y are converted by a floating point formatting part 15 into digital signal samples X′ in the floating-point format, a difference signal ΔX indicating the difference between the digital signal sample X′ and the digital signal sample X is determined by a subtraction part 16, the difference signal ΔX is losslessly coded, and the resulting code sequence Cb is output.
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Citations
24 Claims
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1. A lossless coding method for a digital signal in a floating-point format, comprising:
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(a) a step of converting a first digital signal sample in the floating-point format into a second digital signal sample in an integer format; (b) a step of losslessly compressing a sequence of said second digital signal samples in the integer format to produce a first code sequence; (c) a step of producing a difference signal that corresponds to the difference between said second digital signal sample in the integer format and said first digital signal sample in the floating-point format; and (d) a step of outputting said first code sequence and difference information corresponding to said difference signal as a coding result. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A decoding method for a digital signal in a floating-point format, comprising:
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(a) a step of decoding and expanding a first code sequence to produce a first digital signal sample in an integer format; (b) a step of producing a difference signal based on difference information; (c) a step of converting said first digital signal sample in the integer format into a second digital signal sample in the floating-point format; and (d) a step of combining said second digital signal sample in the floating-point format and said difference signal to produce a third digital signal sample in the floating-point format. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A lossless coder for a digital signal in a floating-point format, comprising:
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an integer formatting part that converts an input first digital signal sample in a floating-point format into a second digital signal sample in an integer format; a first compressing part that losslessly compresses a sequence of second digital signal samples in the integer format to produce a first code sequence; and a difference producing part that produces a difference signal corresponding to the difference between said second digital signal sample in the integer format and said first digital signal sample in the floating-point format, in which said first code sequence and difference information corresponding to said difference signal are output as a coding result. - View Dependent Claims (15, 16, 17, 18, 19)
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20. A decoder for a digital signal in a floating-point format, comprising:
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a first expansion part that receives a first code sequence and decodes and expands the first code sequence to produce a first digital signal sample in an integer format; a floating point formatting part that receives said first digital signal sample in the integer format and converts the first digital signal sample into a second digital signal sample in the floating-point format; a combining part that receives a difference signal based on difference information and combines said difference signal and said first digital signal sample in the floating-point format to produce a third digital signal sample in the floating-point format. - View Dependent Claims (21, 22, 23, 24)
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Specification