Multiple technique entropy coding system and method

• US 20060071827A1
• Filed: 09/21/2005
• Published: 04/06/2006
• Est. Priority Date: 04/17/2003
• Status: Active Grant

• Current Assignee: Straight Path IP Group, Inc. (Verizon Communications Inc.)
• Original Assignee: Droplet Technology Incorporated
• Inventors: Lynch, William C., Saunders, Steven E., Kolarov, Krasimir D.
• Granted Patent: US 7,436,329 B2
• Time in Patent Office: Days
• US Class Current: 341/50
• CPC Class Codes: H03M 7/40 Conversion to or from variable length codes, e.g. Shannon-Fano code, Huffman code, Morse code
• CPC Class Codes: H03M 7/4006 Conversion to or from arithmetic code
• CPC Class Codes: H04N 19/12 Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/18 the unit being a set of transform coefficients
• CPC Class Codes: H04N 19/1887 the unit being a variable length codeword
• CPC Class Codes: H04N 19/42 characterised by implementation details or hardware specially adapted for video compression or decompression, e.g. dedicated software implementation H04N19/635 takes precedence
• CPC Class Codes: H04N 19/60 using transform coding
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A system, method and computer program product having optimal matching to a known or measured probability distribution encodes data without the use of an excessively large lookup table. An encoder constructed according to the present invention uses two or more different encoding methods in combination. In one embodiment, Huffman coding by table lookup is combined with computational generation, such as by using an exponential Golomb equation. The most commonly occurring elements are looked up in a small Huffman table, while the remaining elements are coded with the equation. In another embodiment, data is encoded using two or more equations. In yet another embodiment, data is encoded using multiple tables in conjunction with one or more equations.

Claims

1. A method of compressing data, comprising:

entropy coding an incoming data stream using a combination of at least two coding techniques in parallel, each of the coding techniques processing a different part of the data stream.

2. The method of claim 1, wherein the at least two coding techniques comprise a Huffman lookup table and a computational generation.

3. The method of claim 2, wherein the computational generation is an exponential-Golomb type.

4. The method of claim 2, wherein the incoming data stream comprises a series of symbols to be encoded, each symbol having a magnitude, and wherein symbols having a magnitude less than a fixed constant are coded by using the Huffman lookup table and symbols having a magnitude not less than the fixed constant are coded using the computational generation.