Storage of probability values for contexts used in arithmetic coding

US8378861B2 · kind B2 · utility

Assignee

• Arm Limited · GB

Inventors

• Anders Berkeman · Lund, SE
• Dominic Hugo Symes · Cambridge, GB

Key dates

• Filing date: Nov 29, 2010
• Grant date: Feb 19, 2013
• Expiry date: Jun 21, 2031

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03M7/4018
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

Arithmetic coding utilizes probability values associated with contexts and context indexed values. The probability values are stored within a random access memory 6 from where they are fetched to a cache memory 8 before being supplied to an arithmetic encoder and decoder 4. The context indexed values used are mapped to the plurality of contexts employed such that context indexed values used to process data values close by in a position within the stream of data values being processed have a greater statistical likelihood of sharing a group of contexts than context values used to process data values far away in position within the stream of data values. Thus, a group of contexts for which the probability values are fetched together into the cache memory 8 will have an increased statistical likelihood of being used together in close proximity in processing the stream of data values. This reduces the number of cache flush operations and cache line fill operations.