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Description: LZW coder and decores. C++ classes to encode and decode algorithm
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Size: 3072 |
Author: o27 |
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Description: 熵编码(entropy encoding)是一类利用数据的统计信息进行压缩的无语义数据流之无损编码。本章先介绍熵的基本概念，然后介绍香农-范诺(Shannon-Fano)编码、哈夫曼(Huffman)编码、算术编码(arithmetic coding)、行程编码(RLE)和LZW编码等常用的熵编码方法。 哈夫曼编码建议了一种将位元进位成整数的算法，但这个算法在特定情况下无法达到最佳结果。为此有人加以改进，提供最佳整数位元数。这个算法使用二叉树来设立一个编码。这个二叉树的终端节点代表被编码的字母，根节点代表使用的位元。除这个对每个要编码的数据产生一个特别的表格的方法外还有使用固定的编码表的方法。比如加入要编码的数据中符号出现的机率符合一定的规则的话就可以使用特别的变长编码表。这样的编码表具有一定的系数来使得它适应实际的字母出现机率。-Entropy coding (entropy encoding) is a kind of use data of statistical information compression without semantic data flow of nondestructive coding. This chapter first introduces the basic concept of entropy, and then introduce Shannon- occupies (Shannon- Fano) coding, Huffman (Huffman) coding, arithmetic coding (arithmetic coding), stroke encoding (RLE) and LZW encoding used entropy coding method. Huffman encoding suggest a bit carry into integer algorithm, but this algorithm in specific cases not to achieve the best results. Therefore some improved, providing the best integer bit number. This algorithm using binary tree to set up a code. The binary tree terminal node representing the code letters, on behalf of the root node used bits. In addition to this for each to coded data to create a special form of the method and use fixed code table method. Such as join to coding data symbols appear probability accord with certain rules words can use special variable ChangBian chart. This code
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Size: 18688000 |
Author: 杨飞帆 |
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Description: 实现简单的LZW压缩算法，LZW压缩算法的基本概念：LZW压缩有三个重要的对象：数据流(CharStream)、编码流(CodeStream)和编译表(String Table)。在编码时，数据流是输入对象（文本文件的据序列），编码流就是输出对象（经过压缩运算的编码数据）；在解码时，编码流则是输入对象，数据流是输出对象；而编译表是在编码和解码时都须要用借助的对象。字符(Character)：最基础的数据元素，在文本文件中就是一个字节；字符串(String)：由几个连续的字符组成； 前缀(Prefix)：也是一个字符串，不过通常用在另一个字符的前面，而且它的长度可以为0；
-Achieve a simple LZW compression algorithm, LZW compression algorithm' s basic concept: LZW compression three important objects: data stream (CharStream) encoded stream (CodeStream) and compile Table (String Table). When coding, the data stream is input to the data sequence of objects (text file), encoded stream output object (after compression operation code data) When decoded, the encoded stream is input object, the data stream is output objects while compiling The table is a need to use a means in the encoding and decoding are objects. Character (Character): The most basic data elements, in the text file is a byte string (String): composition by several successive characters prefix (prefix): is a string, but usually used in another in front of the character, and its length can be 0
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Size: 5142528 |
Author: |
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Description: gif文件解码器，实现 lzw 解压算法-gif file decoder to achieve the lzw decompression algorithm
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Size: 73728 |
Author: yinx2003 |
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Description: （利用GIF_LZW算法实现的）网络图片传输
一、使用TCP协议传输数据。理由：稳定性好。
二、使用字节数据流进行传输，理由：
A:VB的String存在自动Unicode转换问题，影响速度；
B:可以直接发送8位字节数据，不需要使用Base64编码，从而减少了编码时间。
三、使用GIF-LZW压缩算法压缩图像。理由：
A:行程编码、Huffman压缩算法压缩率太低；
B:JPEG压缩算法需要太多位运算，且运算量大（有专门MMX优化算法），不利于VB实现；
C:GIF-LZW压缩算法压缩率较好，且我已想出VB语法下高效GIF-LZW压缩/解压算法。
四、使用“有序抖动”算法进行 色彩量化。理由：“有序抖动”处理的结果具有一定规律性，有助于LZW类算法压缩。-(Using GIF_LZW algorithm) network picture transmission one, use the TCP protocol to transfer data. Reasons: good stability. Second, the use of byte data stream for transmission reasons: A: VB' s String automatic Unicode conversion problem exists, impact speed B: You can directly send 8 bytes of data, do not need to use Base64 encoding, thereby reducing the encoding time. Third, the use of GIF-LZW compression algorithm to compress the image. Rationale: A: run-length encoding, Huffman compression algorithm compression rate is too low : JPEG compression algorithm requires too many bit operations, and the large amount of computation (specifically MMX optimization algorithm), and not conducive to the realization of VB C: GIF-LZW compression algorithm The compression ratio is better, and I have come up with the VB syntax efficient GIF-LZW compression/decompression algorithm. Ordered dithering algorithm for color quantization. The reason: " ordered dithering" the results of trea
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Size: 133120 |
Author: 霍小刘 |
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Description: 主要利用测井样本数据测试lzma,zlib,lzw和lzss四种压缩算法的测试性能，并附有测试代码及说明和测试结果-The main use of sample data logging test lzma, zlib, lzw compression algorithm and lzss four kinds of test performance, along with test code and description and test results
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Size: 3035136 |
Author: xiaoyong xie |
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Description: LZW图像压缩算法，详细讲述了BMP转gif的算法原理，请放心下载-LZW image compression algorithm, a detailed account of the algorithm principle BMP to gif, please rest assured download
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Size: 24576 |
Author: 方伟 |
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Description: 本代码由matlab语言编写，实现了jpeg算法，主要为了说明基本的JPEG功能。经过DCT变化，量化，进行DPCM编码，然后之字形扫描AC系数，进行行程（LZW）编码。 显示原始图象和经编码解码后的图象，显示压缩比，并计算均方根误差。-The code consists of matlab language, to achieve a jpeg algorithm, mainly to illustrate the basic functionality of JPEG. After changing DCT, quantization, for DPCM coding, then the AC coefficients of the zigzag scanning, for stroke (LZW) coded. Shows the original image and the encoded decoded image showing the compression ratio, and calculate the mean square error.
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Size: 5120 |
Author: wyd |
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Description: 图像编码源代码，包括：PCX， GIF，LZW算法和GIF数据压缩，JPEG，TGA，TIFF等-Image coding the source code, including: PCX, GIF, LZW and GIF data compression algorithm, JPEG, TGA, TIFF, etc.
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Size: 7168 |
Author: fellpe |
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Description: 多媒体lzw压缩算法源码（c++）
LZW压缩算法是Lempel-Ziv-Welch 3个人共同发明的，简称 LZW 的压缩算法，可以用任何一种语言来实现它.
LZW是GIF图片文件的压缩算法，而且zip压缩的思想也是基于LZW实现的，所以LZW对文本文件具有很好的压缩性能。-lzw compression algorithm source code (c++)
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Size: 199680 |
Author: 云天清 |
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Description: lzw解压缩算法源码
LZW压缩算法是Lempel-Ziv-Welch 3个人共同发明的，简称 LZW 的压缩算法，可以用任何一种语言来实现它.
LZW是GIF图片文件的压缩算法，而且zip压缩的思想也是基于LZW实现的，所以LZW对文本文件具有很好的压缩性能。-lzw decompression algorithm source code LZW compression algorithm is Lempel-Ziv-Welch 3 individual co-inventor, referred LZW compression algorithm, you can use any language to implement it. LZW compression algorithm GIF image files, and zip compression thoughts LZW is also based on the realization, it has good text file LZW compression performance.
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Size: 631808 |
Author: 云天清 |
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Description: 参考网上的资料写的gif编解码。
编码用gdi解析常用图片格式，然后组装成gif
解码吧gif的每一帧转换成dib
gif文件格式网上有很多介绍
gif用的变长lzw压缩算法：
没弄懂原理，只知道过程。压缩取一个字符作为后缀，看看字符串是否存在。存在，用对应的编码作为前缀继续取；不存在把字符串添加到字典，前缀添加到输出流，后缀作为前缀继续取。解压取一个编码看看字典中是否存在。存在用对应的字符串的第一个字符作为后缀，看看当前字符串是否存在，不存在添加到字典中，后缀作为前缀，前缀对应的字符串添加到输出流，继续取；编码不存在，前缀对应的字符串的第一个字符作为后缀（这时当前字符串肯定不存在，字典中下一个可用编码肯定等于刚取出的编码），字符串添加到字典中，编码作为前缀，前缀对应的字符串添加到输出流，继续取。
编码流转换成字节流是按位从低到高的，window是小端模式（低字节在低地址），字节内低位在右边。
24位dib转换成8位dib时使用的八叉树算法
图片拉伸时参考的网上的双线性插值算法。
字典满了位数加一，位数是12时不加-Online reference materials written gif codec.
Encoded using gdi resolve common image formats, and then assembled into a gif
Each frame decode it into a gif dib
There are many online gif file format introduced
gif lzw with variable length compression algorithm:
Did not understand the principle, only know the process. Compression takes a character as a suffix, and see if there is a string. Exist as a prefix to continue to take with the corresponding encoding there is no string to add to the dictionary, a prefix added to the output stream, the suffix as a prefix to continue to take. Take a look at extracting coding dictionary exists. Exist with the corresponding first character string as a suffix to see the current string exists, there is no add to the dictionary, the suffix as a prefix, the corresponding string to the output stream, continue to take coding does not exist, prefix corresponding first character string as a suffix (when the current string certainly does not exis
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Size: 438272 |
Author: 朱伯虎 |
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Description: Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempel and Ziv in 1978. The algorithm is simple to implement, and has the potential for very high throughput in hardware implementations.
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Size: 436224 |
Author: fatihafifi |
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Description: Lempel–Ziv–Welch (LZW) is a universal lossless data compression algorithm created by Abraham Lempel, Jacob Ziv, and Terry Welch. It was published by Welch in 1984 as an improved implementation of the LZ78 algorithm published by Lempel and Ziv in 1978. The algorithm is simple to implement, and has the potential for very high throughput in hardware implementations.[1] It is the algorithm of the widely used Unix file compression utility compress, and is used in the GIF image format.
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Size: 16336896 |
Author: van |
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Description: 无损压缩算法代码——
compress.zip
huf.zip
huff_file.zip
huff_stream.zip
lz77.zip
lzw.zip
rle_zip_8bit.zip
rlezip_16bit_sc.zip(Lossless compression algorithm code ----
compress.zip
huf.zip
huff_file.zip
huff_stream.zip
lz77.zip
lzw.zip
rle_zip_8bit.zip
rlezip_16bit_sc.zip)
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Size: 19456 |
Author: Vinley
|
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Description: 无损压缩算法代码——
Lossless compression algorithm code ----
compress.zip
huf.zip
huff_file.zip
huff_stream.zip
lz77.zip
lzw.zip
rle_zip_8bit.zip
rlezip_16bit_sc.zip(Lossless compression algorithm code ----
compress.zip
huf.zip
huff_file.zip
huff_stream.zip
lz77.zip
lzw.zip
rle_zip_8bit.zip
rlezip_16bit_sc.zip)
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Size: 6144 |
Author: Vinley
|
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