US 6,289,130 B1 · Method for real-time lossless data compression of computer data

Abstract

A data compression scheme as described which improves upon and is compatible with the V.42bis data compression standard of the International Telecommunications Union (ITU). The data compression scheme provides an efficient algorithm to determine when as well as how to efficiently switch between transparent and compressed modes to provide and facilitate an improved compression ratio. Additionally, a temporary buffer is provided for use by the encoder in determining which of either transparent or compressed mode provides a more efficient transfer of a portion of data. In making a determination to transition between transmit modes, the incurred overhead associated with such transitions is also taken into account. An approach for evaluating when to discard a particular dictionary that has become inefficient is also provided thereby enabling an improvement in the transmission of multimedia data and the regeneration of a dictionary more representative of the presently evaluated data type.

Claims21

Dependent claims

In a data communication device employing a data compression scheme capable of transmitting data in one of a compressed mode and a transparent mode, a method for determining a preferred mode of said compressed mode and said transparent mode for transmitting said data, said method comprising the steps of:

a. buffering a present portion of said data for transmitting in a transparent look-ahead buffer in said communication device;
b. encoding said present portion of said data for transmitting into corresponding codewords from a present compression dictionary;
c. buffering said codeword in a compression look-ahead buffer;
d. upon the filling of one of said look-ahead buffers, firstly comparing the relative fullness of each of said look-ahead buffers to determine a fullness ratio;
e. secondly comparing said fullness ratio against a preferred mode transition threshold;
and
f. when said preferred mode transition threshold dictates a mode transition, transitioning from a present mode of one of said compressed mode and said transparent mode to said preferred mode of one of said compressed mode and said transparent mode for transmitting said present portion of said data.

4 more elements

In a data communication device, a method for transmitting data in one of a compressed mode and a transparent mode, said method comprising the steps of:

a. determining a preferred mode of said compressed mode and said transparent mode for transmitting said data, said determining step comprising the steps of:
i. buffering a present portion of said data for transmitting in a transparent look-ahead buffer in said communication device;
ii. encoding said present portion of said data for transmitting into corresponding codewords from a present compression dictionary;
iii. buffering said codeword in a compression look-ahead buffer;
iv. upon the filling of one of said look-ahead buffers, firstly comparing the relative fullness of each of said look-ahead buffers to determine a fullness ratio;
v. secondly comparing said fullness ratio against a preferred mode transition threshold;
vi. when said preferred mode transition threshold dictates a mode transition, transitioning from a present mode of one of said compressed mode and said transparent mode to said preferred mode of one of said compressed mode and said transparent mode for transmitting said present portion of said data;
b. selecting said look-ahead buffer corresponding with preferred mode;
and
c. transmitting one of said present portion of said data and said corresponding codewords.

7 more elements

In a data communication device employing a data compression scheme capable of transmitting data in one of a compressed mode and a transparent mode, a computer-readable medium having computer-executable instructions for determining a preferred mode of said compressed mode and said transparent mode for transmitting said data, said computer-executable instructions for performing the steps of:

a. buffering a present portion of said data for transmitting in a transparent look-ahead buffer in said communication device;
b. encoding said present portion of said data for transmitting into corresponding codewords from a present compression dictionary;
c. buffering said codeword in a compression look-ahead buffer;
d. upon the filling of one of said look-ahead buffers, firstly comparing the relative fullness of each of said look-ahead buffers to determine a fullness ratio;
e. secondly comparing said fullness ratio against a preferred mode transition threshold;
and
f. when said preferred mode transition threshold dictates a mode transition, transitioning from a present mode of one of said compressed mode and said transparent mode to said preferred mode of one of said compressed mode and said transparent mode for transmitting said present portion of said data.

4 more elements

Dependencies are inferred from the claim text.

Method for real-time lossless data compression of computer data

Life of this patent

Method for real-time lossless data compression of computer data

Life of this patent

Abstract

Claims21