Patent ID: 6870491
Filing Date: 2005-03-22
Classification: H03M,H04N

Abstract:
1. A method of decoding compressed image data, comprising: receiving compressed image data in the farm of an input data stream including first and second parameters having initial values and which are representative of properties of the data stream, and a third parameter having a value which is representative of a decoding property of a decoder; and arithmetic decoding of the received compressed image data, wherein the arithmetic decoding of the received data includes a combination of parallel and serial processing steps to reduce processing time wherein decoding the received compressed image data further comprises: determining a value for a reference parameter as a function of the third parameter using a lookup table, in parallel, computing first and second subtraction values using initial values of the first and second parameters; computing an updated value for the second parameter by adding the computed second subtraction value to the determined value of the reference parameter, in parallel, computing an updated value for the first parameter using the initial value of the first parameter and the determined value for the reference parameter; comparing the determined value of the reference parameter with the computed first subtraction value; and outputting the undated values for the first and second parameters based on the outcome of the comparison.