Multiple Technique Entropy Coding System and Method

• US 20110234431A1
• Filed: 06/07/2011
• Published: 09/29/2011
• 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 8,947,271 B2
• Time in Patent Office: Days
• US Class Current: 341/51
• 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 7/4075 Golomb codes
• 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 19/134 characterised by the element, parameter or criterion affecting or controlling the adaptive coding
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• 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 19/60 using transform coding
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic 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;

wherein the at least two coding techniques comprise a Huffman lookup table and a computational generation; and

the incoming 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.

2. A method of compressing data, comprising:

using a combination of at least two coding techniques to encode an incoming data stream having more than one portion;

calculating a value for each portion of the incoming data stream according to an algorithmic analysis;

selectively applying a first one of the at least two coding techniques to the portions of the incoming data stream that have values greater than a first threshold value.

3. The method of claim 2, further comprising:

selectively applying a second one of the at least two coding techniques to portions of the incoming data stream that have values less than the first threshold value.

4. The method of claim 2, further comprising:

selectively applying a second one of the at least two coding techniques to portions of the incoming data stream that have values less than the first threshold value but greater than a second threshold value.

5. The method of claim 4, further comprising:

selectively applying a third one of the at least two coding techniques to portions of the incoming data stream that have values less than the second threshold value.

6. A system comprising:

means for encoding an incoming data stream having more than one portion using a combination of at least two coding techniques;

means for assigning a value to each of the portions of the incoming data stream;

means for applying a first coding technique when the value of any portion of the incoming data stream is greater than a first threshold value.

7. The system of claim 6, further comprising:

a means for applying a second coding technique when the value of any portion of the incoming data stream is less than the first threshold value.

8. The system of claim 6, further comprising:

a means for applying a second coding technique when the value of any portion of the incoming data stream is less than the first threshold value but greater than a second threshold value.

9. The system of claim 8, further comprising:

a means for applying a third coding technique when the value of any portion of the incoming data stream is less than the second threshold value.