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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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iText: Error extracting images -- getting NullPointerException in LZWDecoder

I am using iText v5.4.2. I am trying to parse images from a PDF file. I get NullPointerException for certain images in certain PDF files. The PDF file with one "faulty" image can be downloaded here:…
Maksim Sorokin
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LZW decoding miss the first code entry

I followed the Rosetta Java code implementation. I tried do this LZW coding with my own Dictionary and not with the ASCII Dictionary which was used. When I try with my own Dictioanry there is a problem about decoding... The result is wrong, because…
blaces
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PERL LZW compression with output codes are 9 bits long

From the Page : http://www.verypdf.com/document/pdf-format-reference/pg_0072.htm I am trying use the same details to compress and decompress , it not working any perl modules (LZW) Source ASCII codes : 45 45 45 45 45 65 45 45 45 66 Current Output…
Tree
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Array of variable length strings for lzw compression

Right here is the function itself. I'm having a segfault in there because apparently I'm unable to assign the string to that value in the array. clang/gcc both give me a warning. Clang's is a bit better which is "expecting char assigning char *". I…
133794m3r
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GIF Understanding Image Decoding - Lempel-Ziv-Welch

I'm trying to build some code I can use to convert a GIF file to another file format (which I already know how to create. [I am trying to streamline conversion from GIF to GRF - a printer graphic file format.]) I am working off of information from…
teynon
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Trouble understanding php function for LZW decompression in JSend

I'm trying to convert the LZW decompressor from JSend which is in php to javascript, and I've gotten to a function I can't quite make sense of. private static function decompressLZW($aCodes) { $sData = ''; $oDictionary = range("\x0000",…
AdamB
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Lossless compression theory, is compression ratio based on size of pattern and times repeated?

I was wondering which of the following scenarios will achieve the highest ratio with lossless algorithms applied to binary data with repeated data. Am I correct to assume the compression ratio depends on patterns? Size Times repeated For example…
chineerat
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LZW Data Compression In Lua

Possible Duplicate: LZW Compression In Lua Here is my code for compressing data in Lua using the LZW compression method. My problem is that the function is returning the character 'T', instead of returning the full compressed string…
Nicholas Rubin
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LZW compression & dictionary

I'm looking into implementing LZW compression in C++, and not sure of the best dictionary implementation. Hash table made sense, but I don't understand how I would be able to 'reassign' values. If the table gets full, I need to be able to start…
DillPixel
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is it possible to make lzw compression/decompression parallel?

i have read this article on how to compress/decompress data using LZW but i'm looking to make it use multiple threads... but i think it is not possible. what do you think? any papers or articles on this subject? or even hints on how to do it.
Hannoun Yassir
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Java LZW Compresss & Decompress with Image

I've checked many sources about LZW compression but it didn't work with image file. Here are the resources what I have checked so far: https://www.codemiles.com/java/lzw-data-compression-decompression-algorithm-java-code-t99.html This one the…
Chhorn Soro
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why strcat producing this error?

[Warning] passing argument 1 of 'strcat' makes pointer from integer without a cast THIS ERROR IS COMING WHEN I AM USING STRCAT WHAT SHOULD I DO , below is my code #include #include void main() { char a[20], b[256], p =…
Rachit
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Can I use dll in Turbo C++ program and do we have any dll for lzw compression and decompression

I was trying to create a lzw compression program. But i need to finish it by today itself so i want to use some dll for taking my input as txt file and output to as a text file. I want to do this in TURBO C++ code which are doing my remaining…
Shantanu Gupta
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LZW encoding for large file

I am building an LZW encoding algorithm, which uses dictionary and hashing so it can reach fast enough for working words already stored in a dictionary. The algorithm gives proper results when ran on smaller files (cca few hundreds of symbols), but…
Whizzil
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LZW in matlab how can I put the image to the LZW algorithm

Thank you in advance for you help, my question is I am doing LZW compression in Matlab , I choose the image through a selection dialog box then I read the image by imread command after that I do not know what to do or how to do what I have is the…
Wadha Abdullah
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