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Integer Length Arithmetic Code for Conditional Binary Sources

IP.com Disclosure Number: IPCOM000054702D
Original Publication Date: 1980-Mar-01
Included in the Prior Art Database: 2005-Feb-13

Publishing Venue

IBM

Related People

Authors:
Langdon, GG Rissanen, JJ [+details]

Abstract

The objective is to encode "runs" 0 ...01, where the probability of the least probable symbol (LPS), say "1", is taken of the form 2/- k(s)/, k(s) being an integer, the "skew" number depending on the past string s. The length of that LPS is then l(LPS) = k(s), while the length of the opposite most probable symbol (MPS) is a fractional number l(MPS). The length of the entire run with 0's and a 1 is l, (MPS) + ... + + l(r) (MPS) + l(r+1) (LPS), which will be rounded up to an integer, say, l(r), by adding .75 to the length and taking the floor function thereof. These operations are done in the first two adders. For such a run the encoder forms an addend recursively for i = 1, ..., r-1, as follows: See Original. and adds it to the augend which is the code string.