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Thread: TC 5.1dev2 is here!

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    Okay, here are the new TC with flexible parsing. This version is fully compatible with previous one.

    Link:
    Download TC 5.1dev2 (25 KB)


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    can you more increased compression?

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    Yes, compression can be improved even without any decoder modifications. For example, the flexible parsing have some additional parameters. Due to this fact, compression ratio can be improved in cost of speed. Currently TC uses a fast variant of flexible parsing wich is slightly slower than greedy parsing and in most cases provides higher compression. In addition, I have a slower version of this parser, wich provides even more higher compression, especially on text files, but in some cases this flexible parser can provide a slightly lower compression, that's why I keep a fast version. But in future, I think I add the stronger version of this parser. Note, that's not all. Also I can add additional tricks like multiple passes, etc.


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    Thanks Ilia!

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    By the way, read the excellent paper about Flexible parsing:

    http://www.arturocampos.com/ac_flexible_parsing.ht ml


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    Its awesome stuff but when will you be adding the switches to choose compression mode (Fast, Normal, Max) that you mentioned?

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    Well, currently I'm experimenting with TC. Including with algorithm parameters to find the best settings for 'Fast' and 'Max' modes. (and later, 'Normal' mode).

    Max - for max compression at any cost (current version, at least temporarily)
    Fast - encoder works with some restrictions to improve speed

    Note, the decoder stays untouched and must have a fast speed and low memory usage - these conditions restricts the compression power. But asymmetric nature is the goal of this engine.

    Currently, Fast mode is about 2x times faster than Max.

    Some compresison results:

    world95.txt
    Fast: 795,778 bytes
    Max: 671,748 bytes

    acrord32.exe
    Fast: 1,732,095 bytes
    Max: 1,707,217 bytes

    Like you see, here we have a big compresison loss on Text file, but just a small one on Binary data.


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    P.S.
    If this looks fine, I can add the Fast mode to the next version. (the 'f' switch, additionally to the new 'x' (current 'e') and 'd')


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    usage: tc <command> <infile> <outfile>
    valid commands are:
    f - encode using 'fast' mode
    x - encode using 'max' mode
    d - decode

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    Okay, and here are the special compile of the TC 5.1dev2 - TC 5.1dev2-fast-edit for Fast mode evaluation only. This TC is fully compatible with TC 5.1dev2.

    http://www.encode.su/downloads/tc-5.1dev2-fast-edit.zip

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    But, IMHO, adding multiple modes must be avoided, until the real 'Max' mode will be added.


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    Max - for max compression at ANY COST (current version, at least temporarily)

    Excellent! This is what we want!


    Fast - encoder works with some restrictions to improve speed

    Good idea! I think it will make TC more popular with three compression modes going from LZPX type compression and speed to almost PAQ-like super-high compression!

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    Can't wait for the next release of tc with its three powerful compression modes!

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    Well, about next version. I think it will have one compression mode again. But... Malcolm Taylor tell me details and specifications about his marvelous ROLZ2 and ROLZ3. Some of his ideas I already implement in next version. Currently new version have higer compresison (as BZIP2 at MFC or higher) and now I'm working on decompression speed - it will be again faster. Also performance on large files (ENWIK8/ENWIK9/MFC) will be noticeable improved. But compression speed will be slower.


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    Also performance on large files (ENWIK8/ENWIK9/MFC) will be noticeable improved. But compression speed will be slower.

    I like the idea of much higher compression. I really hope this will put TC in the top ten!

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