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Questions tagged [lzw]

LZW (Lempel-Ziv-Welch) is a compression algorithm which supersedes LZ78.

LZW (Lempel-Ziv-Welch) is a compression algorithm which supersedes LZ78.

You can find more information about LZW on Wikipedia.

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What is the first sign at that Lempel-Ziv-Codierung

I know what the second and the third sign mean at <0|0|A> but what means the first?? Why is the first sigh 7 at the last group(<7|1|#>)?? With frindly wishes sniffi
sniffi
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Error when trying to encode

Why can't I use sourcecode = "myFile.txt" f = open(sourcecode, mode='rb') to open my file and compress it? This is all pretty new to me. I would be glad if some of you could give me some advice on how to solve the problem. def…
Haris Saric
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Encoder and Decoder

Other way to encode byte[] to String and decode String to byte[] without using Base64. Because when I encode a byte[] to String and then I compress the String using LZW. I can't decode it back to byte[] using Base64. Is there an encoder or decoder…
Satria Winarah
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unable to read tiff with lzw compression for jai codec api

I am unable to read tiff file by using jai codec API which is having LZW compression technique. The below lines I am using to render tiff image. PlanarImage pImage = new NullOpImage(renderedImage, null, null, OpImage.OP_IO_BOUND); firstImage =…
sriram
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Understanding an example of LZW decompression algorithm

I'm trying to understand this example of decompression using the LZW algorithm. I would like to undestand why we insert ba in row 4; we're currently at i=3, so the index s=ab as shown in row 3; we previously had a and b so aren't we supposed to…
napi15
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How to detect codeword length for LZW Decoding

I'm writing a general LZW decoder c++ program and I'm having trouble finding documentation on the length (in bits) of codewords used. Some articles I've found say that codewords are 12bits long, while others say 16bits, while still others say that…
Stanton
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lzw string - Sending via AJAX

I am using LZW algorithm for stringified JSON object to reduce size. Size reduction is fantastic, but I am having problems transmitting compressed string via AJAX because of URL malformed error. If I encode it with base64, the size goes up…
Zaay
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Decompressing Animated GIF Raster Data

Sorry for the lengthy post I'm trying to give as much information as I can and I did my best to format everything to be as easily readable as possible. I've been trying to decompress GIF's in C# and seem to have everything except the LZW…
Dan Flanagan
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A LZW compression and decompression in python

I'm doing a variation of the basic Lempel-Ziv compression in python (2.7). The case is, this algorithm would usually output a list composed by characters and integers, the last ones designating the order of each new string in the dictionary. Now,…
stonebird
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Javascript - Alternative to lzw compression for Database entry

I have strings (about 1-5Kb) of the form: FF,A3V,X7Y,aA4,.... lzw compresses these really nicely, but includes Turkish characters. These are then submitted to a MySQL database. Sometimes MySQL can 'play-up' and not submit these properly, putting…
Rewind
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Trouble with compression in LZW

I'm having trouble while implementing the compressor of the LZW. The compressor seems to work fine but while processing some streams it doesn't put the end of stream character (defined with the value 256), the result is that the decompressor will…
damaar
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Can anyone recommend a lossless compression algo for compressing x and y coordinates?

I am needing some advice on a compression algo to compress x and y data coordinates. I am coding in Matlab. I have been doing quite a bit of research and came across Huffman Coding,LZW, Delta etc. What I can figure out from Huffman is, data needs to…
Hitmanpaddy
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Library to compress arbitrary data structures in Python

I have an application written in Python that stores many lists of basic datatypes (int, floats etc) which are in turn rarely accessed. I was looking at some libraries that could compress this data before further processing. I looked at gzip and…
igon
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Reading integers from a file c++

I implemented an LZW compressor which encodes the strings into integers with the help of a hash function. I stored the coded string in a text file. Now I need to decompress the same code. I am confused how to differentiate between a two digit…
Cherry Cool
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Reading LZW compressed images using Bitmiracle Libtiff.net

Currently I am trying to utilize libtiff.net library for processing digital Tiff images. but the image that I have is not with standard ones. The image contains 3 samples per pixel. And it is LZW compressed. My question is: how to read the value of…
Programmer2.0
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