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Questions tagged [data-compression]

156 questions
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redirect output to compressed format (C)

Is it possible to use fprintf in such a way that write data to a compressed file? For example: fopen ("myfile.txt","w"); will write to a plain text file. So the file size grows very large.
mahmood
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Recommended Resources for Data Compression Research

I'm looking for recommended resources on data compression; any studies on techniques, data structure and/or algorithms; any useful resources related to research, any books, organizations or any other information would be helpful. I know it's kind of…
Fostah
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Alternatives to GZIPInput/OutputStream with better compression ratios?

I need to store abitrary binary data (essentially files of various common formats, JPEG, PDF, MS-Office and some other odd files). Slow compression is not a problem, but I'm looking for reasonably fast decompression and as good a compression ratio…
Durandal
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Redshift copy creates different compression encodings from analyze

I've noticed that AWS Redshift recommends different column compression encodings from the ones that it automatically creates when loading data (via COPY) to an empty table. For example, I have created a table and loaded data from S3 as…
spinnn
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Explanation about hashing and its use for data compression

I am facing an application that uses hashing, but I cannot still figure out how it works. Here is my problem, hashing is used to generate some index, and with those indexes I access to different tables, and after I add the value of every table that…
Eduardo
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Streaming mode vs block mode

I can't figure out what exactly is the streaming mode offered by modern compression/decompression algorithms (eg ZStandard or LZ4) and how I can exploit it. As an example, suppose I have 4x16KB file. I can (individually) compress each file and…
xmas79
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Store SHA-1 in database in less space than the 40 hex digits

I am using a hash algorithm to create a primary key for a database table. I use the SHA-1 algorithm which is more than fine for my purposes. The database even ships an implementation for SHA-1. The function computing the hash is returning a hex…
MaNa
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Does CompressorHttp2ConnectionEncoder can identify already compressed contents?

I have implemented a HTTP/2.0 server which supports compression using Netty 4.1.5.Final.CompressorHttp2ConnectionEncoder class which is used for HTTP data frame compression. It uses content-encoding Transport header field to identify the compression…
Anuradha Niroshan
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Analyze what compression type use for table

I have SQL Server 2014 database. As size of this database isn't small I want to apply data compression to it. I've used sp_estimate_data_compression_savings to check what how many size I can save and I thought that I should apply that compression…
demo
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sending large JSON data from android to php server can I compress?

i am sending large datasets in JSON format from my android device to my server (using PHP). I want to keep bandwidth costs down. I am wondering: should I gzip compress the JSON data server side before sending the data? is there a javascript gzip…
Sanjay Bhalani
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Combining lossless data compression algorithms

I was wondering about how far we can take lossless data compression; I wasn't able to find an online simulator of lossless algorithms to perform some empiric testing. I could just make one on my own, but unluckily I don't have enough time in this…
kelo
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parsing large compressed xml files, python

file = BZ2File(SOME_FILE_PATH) p = xml.parsers.expat.ParserCreate() p.Parse(file) Here's code that tries to parse xml file compressed with bz2. Unfortunately it fails with a message: TypeError: Parse() argument 1 must be string or read-only…
Marcin
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Convert high-resolution images to low-resolution

I am doing a web project on media manager. I upload high resolution images and need to convert these images to low resolution, so that the resulting image is compressed into a smaller size. How is this possible using Java? Please post source code,…
naveen
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Network Data Optimization for Windows-based VPN

I am looking for ways to embed compression in a VPN setup so that users connecting from mobile devices to the VPN server will be able to decrease their bandwidth consumption and save up on their data plans. Does anyone know of a good…
user1151659
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Large querystring compression

Possible Duplicate: How to compress/decompress a long query string in PHP? I have a huge amount of data inside my subquerystring for tracking needs. I loose a lot of my data because of this too large url missinterpreted by clients or search…
Dark
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