Patent ID: 6188334
Filing Date: 2001-02-13
Classification: H03M

Abstract:
A method for encoding data, the data represented by a symbol string populated by more probable symbols (""MPS"") and less probable symbols (""LPS""), the method comprising the steps of:initializing a code accumulator S;defining a coding interval extending from a variable lower bound A to a constant upper bound 1;for each position in the symbol string:computing a test value Z subdividing the coding interval into sub-intervals in accordance with the relative probabilities of an MPS and an LPS occur in the position, a first sub-interval extending from the lower bound A to the test value Z, the second sub-interval extending from the test value Z to 1;if the symbol located at the current position in the symbol string is a MPS, setting the lower bound A to the test variable Z for use in encoding of a next position in the decoded symbol string;if the symbol located at the current position in the symbol string is an LPS,adding the length of the second sub-interval to the accumulator S, andcomputing a new lower bound A for use in encoding of a next position in the decoded symbol string; andwhen a predefined criterion is met, outputting a segment of coded data and computing new values for both the accumulator S and the lower bound A.