System Based Compression Software

8/4/2019 System Based Compression Software

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COMPRESSION

SOFTWARE

PROJECT GUIDE

MS. KAVITA SAXENA

DEVELOPED BY:

NIKHIL GUPTA

MANAN SEHGAL

MUKUL GOEL


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INTRODUCTION

ZIP SOFTWARE allows us to reducenumbers of bits and bytes so that itcan be transmitted over slower

Internet connection. It is a system based software and user

need not to depend on third partys

software like WINZIP, WINRAR..etc. Different compression/decompression

techniques are used.


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IEEE PAPERS ANDRESEARCH A new lossless method of image

compression and decompression usinghuffman coding techniques By JAGADISHH. PUJAR and LOHIT M.KADLASKAR.

Data Compression By Debra A. Lelewerand Daniel S. Hirschberg

http://www.johnwiseman.com/technical/MPEG_tuto

rial.htm http://www.ics.uci.edu/~dan/pubs/DataCompressio

n.html
http://www.johnwiseman.com/technical/MPEG_tutorial.htmhttp://www.johnwiseman.com/technical/MPEG_tutorial.htmhttp://www.ics.uci.edu/~dan/pubs/DataCompression.htmlhttp://www.ics.uci.edu/~dan/pubs/DataCompression.htmlhttp://www.ics.uci.edu/~dan/pubs/DataCompression.htmlhttp://www.ics.uci.edu/~dan/pubs/DataCompression.htmlhttp://www.johnwiseman.com/technical/MPEG_tutorial.htmhttp://www.johnwiseman.com/technical/MPEG_tutorial.htm


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ALGORITHMS USED:

GZIP ALGORITHM

RUN LENGTH ENCODING (RLE)

LEMPEL ZIV WELCH (lZW)

HUFFMANCOMPRESSION/DECOMPRESSION


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Differences with existingsystems.

Dependence on third party software

Existing system require morecomputational time.


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DATA FLOW FOR SYSTEM


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GZIP(GNU ZIP) ALGORITHM

It finds duplicated strings in the input data.

The second occurrence of a string is

replaced by a pointer to the previous string,

in the form of a pair (distance, length). Distances are limited to 32K bytes, and

lengths are limited to 258 bytes. When a

string does not occur anywhere in the

previous 32K bytes, it is emitted as a

sequence of literal bytes.


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Literals or match lengths arecompressed with one Huffman tree, andmatch distances are compressed withanother tree.

The trees are stored in a compact form

at the start of each block.

Duplicated strings are found using ahash table. All input strings of length 3

are inserted in the hash table.


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RUN LENGTH ENCODING(RLE) Run-length encoding (RLE) is a very

simple form of data compression in which

runs of data (that is, sequences in which

the same data value occurs in manyconsecutive data elements) are stored as

a single data value and count, rather than

as the original run. wwwwwwaaaaabbbbbsssddddd. Will be

stored as : 6w5a5b3s5d


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LENPEL ZIV WELSH (LZW)

Its a form of

compression/decompression techniquewhich makes use of a dynamic dictionaryfor encoding as well as decoding aparticular stream of data.

LZW dictionary is not an externaldictionary that lists all known symbol

strings. Instead, the dictionary isinitialized with an entry for every possiblebyte.


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HUFFMAN ALGORITHM

Huffman coding is an entropy encodingalgorithm used for lossless datacompression.

The term refers to the use of a variable-length code table for encoding a sourcesymbol (such as a character in a file)where the variable-length code table hasbeen derived in a particular way basedon the estimated probability ofoccurrence for each possible value of the

source symbol.


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Huffman coding uses a specificmethod for choosing the

representation for each symbol,resulting in a prefix code ) thatexpresses the most common

source symbols using shorterstrings of bits than are used forless common source symbols.

The technique works by creatinga binary tree of nodes.


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TECHNOLOGICAL PLATFORM

JAVA SDK 1.6

OS WINDOWS 7

NETBEANS 6.9.1

JAVA.UTIL.ZIP main package used.


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WORK DONE TILL NOW

Through with programming phase.

Testing is undergoing.

Working better than current ZIP

software.

System Based Compression Software

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