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Questions tagged [data-compression]

156 questions
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Is there a definitive order to perform data compression and encryption

I have a requirement stating that data compression and encryption should be performed. However, I have doubts relating to which step should be performed first in order to optimize compression rate and execution time. How can I choose which step to…
venkat
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Data compression for microcontroller

I am doing a project with a PIC microcontroller. I have an ADC sampling and saving data to a RAM memory, once the RAM is filled I need to send it via Bluetooth with a PIC microcontroller. My data is very redundant, I have about 10-20 consecutive…
Andres
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How compress data in memory buffer by using libbz2 library in C program

I try to compress memory data by using libbz2 library in C program. Should I use this function of libbz2?: int BZ2_bzCompress ( bz_stream *strm, int action ); Can anyone show me an example? Thank you.
ziguli
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Compression of strings in different databases

Can mysql-server-express compress strings? if you could give me a link to some documentation that says so it will be much appreciated as I can't seem to find this info. I know that mysql allows this by using the compress() Function on the string.…
michelle
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How do you store raw bytes as text without losing information in python 2.x?

Suppose I have any data stored in bytes. For example: 0110001100010101100101110101101 How can I store it as printable text? The obvious way would be to convert every 0 to the character '0' and every 1 to the character '1'. In fact this is what…
Manuel Araoz
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Compressing measurements data files

from measurements I get text files that basically contain a table of float numbers, with the dimensions 1000x1000. Those take up about 15MB of space which, considering that I get about 1000 result files in a series, is unacceptable to save. So I am…
Jakob
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Converting string of 1s and 0s into binary value, then compress afterwards ,PHP

I have a string for example: "10001000101010001" in PHP I am compressing it with gzcompress, but it compresses ASCII equivalent. I would like to compress the string as if it were binary data not it ASCII binary equivalent. Bascially I have 2…
chineerat
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How to reduce a bigger string in smaller string in C++? Probably by hashing?

I want to compress a bigger string into a smaller string in C++. What are the different ways to do this in C++? The requirement is that output should also be a string.
Sam
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Question about the compressibility of certain groups of numbers

Lets say we have a bunch of numbers that increment in small values from a large offset eg offset = 123456789 our numbers are: 123456790 123456791 123456793 123456796 123456799 123456804 if we subtract the offset from these numbers we…
rolls
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Best way to transfer a large number of BMP images

On a remote machine, I have a number of BMP images that I want to transfer to my computer as fast as possible. These images are very similar (frames from a single scene in a video). I do not want to lose any information. I tried zipping but zipping…
Vukasin Rankovic
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What compression class does the BLP image file format uses?

Does the BLP file format only use lossy-compression, lossless-compression, or both depending on the compressor? I haven't been able to find a concrete answer to this. Lossy and lossless image compression.
user7393973
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Need help in compression algorithm identification

Not quite sure that this is a StackOveflow question, but however. Currently I'm in reversing an old MS-DOS Neuromancer game (Interplay Productions, 1988. Based on William Gibson's novel). For now I have already written an utility that parses game…
Henadzi Matuts
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If I use AWS DMS to migrate data from uncompressed Oracle DB to compressed DB, will I lose the compression on target DB?

This is a data refresh activity. My source DB is Oracle 11g. I am using AWS DMS to migrate the data from source to target DB Oracle 12c on which compression is applied. By doing so will I lost the compression on target DB? And if yes, is there any…
Bhagabat Behera
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Cassandra Compression Ratio is 0 although LZ4Compressor used

I have create a keyspace and table within it for documents store. The code I used is CREATE KEYSPACE space WITH replication = {'class':'SimpleStrategy', 'replication_factor' : 3}; USE space; CREATE TABLE documents ( doc_id text, …
Szymon Roziewski
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Reduce the number of rows in a binary table

I have a table with a 38 bit binary string at every address. I am trying to figure out what would be the best way of reducing the depth of the table? Say for example that I have 1024 addresses and I want to reduce it to about 100 addresses, such…
user439569
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