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Thread: Lempel-Ziv-Tamayo

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    Lempel-Ziv-Tamayo

    Another LZ algorithm :




    lzgt1 is one of a group of free, open source, experimental file compressors by Gerald R. Tamayo, released July 17, 2008. It uses LZT (Lempel-Ziv-Tamayo) compression, a LZ77 variant in which the decompressor rebuilds a list of matches sorted by context match length and the match length is implied or partially implied by the position in the list. lzgt implements LZT using a 4K sliding window, 32 byte look-ahead buffer and 3 bit code length. lzgt1 is like lzgt but uses a 16K sliding window and 128 byte look-ahead buffer. lzgt2 eliminates the code length entirely. lzgt3 is an improved version of lzgt2. All programs have separate decompressors (lzgtd1, etc) and are compiled for DOS (and Windows).

    LZGT3A.ZIP - contains simple LZ77/LZSS programs which illustrate that there is another "information" in the transmitted window <position> code, aside from being a mere pointer to the location of the longest string in the sliding window. That "information" refers to the partially matched strings, and clearly demonstrates that LZ77's output strings are of "unbounded" length. In theory, the method improves compression performance of "all LZ77/LZSS algorithms that use a sliding window and output a <position, length> pair of codes." However, decompression speed (the very hallmark of LZ77 coding) suffers to a large degree which makes the algorithm a mere theoretical (and empirical) curiosity.


    http://compgt.googlepages.com/lzgt3a.zip

    Website:

    http://compgt.googlepages.com/lz77


    LTCBTest:

    http://cs.fit.edu/~mmahoney/compression/text.html#4033
    Last edited by lunaris; 19th July 2008 at 03:18.

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    Extremely slow decompression in pair of poor compression...

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    Yes encode , The algorithm is not optimized yet. But it can be.

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    Quote Originally Posted by lunaris View Post
    Another LZ algorithm :




    lzgt1 is one of a group of free, open source, experimental file compressors by Gerald R. Tamayo, released July 17, 2008. It uses LZT (Lempel-Ziv-Tamayo) compression, a LZ77 variant in which the decompressor rebuilds a list of matches sorted by context match length and the match length is implied or partially implied by the position in the list. lzgt implements LZT using a 4K sliding window, 32 byte look-ahead buffer and 3 bit code length. lzgt1 is like lzgt but uses a 16K sliding window and 128 byte look-ahead buffer. lzgt2 eliminates the code length entirely. lzgt3 is an improved version of lzgt2. All programs have separate decompressors (lzgtd1, etc) and are compiled for DOS (and Windows).

    LZGT3A.ZIP - contains simple LZ77/LZSS programs which illustrate that there is another "information" in the transmitted window <position> code, aside from being a mere pointer to the location of the longest string in the sliding window. That "information" refers to the partially matched strings, and clearly demonstrates that LZ77's output strings are of "unbounded" length. In theory, the method improves compression performance of "all LZ77/LZSS algorithms that use a sliding window and output a <position, length> pair of codes." However, decompression speed (the very hallmark of LZ77 coding) suffers to a large degree which makes the algorithm a mere theoretical (and empirical) curiosity.


    http://compgt.googlepages.com/lzgt3a.zip

    Website:

    http://compgt.googlepages.com/lz77


    LTCBTest:

    http://cs.fit.edu/~mmahoney/compression/text.html#4033
    Thanks lunaris!

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    Quote Originally Posted by lunaris View Post
    All programs have separate decompressors (lzgtd1, etc) and are compiled for DOS (and Windows).
    I feel obligated to let you know of two things: (Please, no flames, I meant no harm!)


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