Compression decreases the size of data.

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2
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0answers
23 views

Zipping a text file with sha256 hashes seems too efficient

I have an ASCII-encoded text file where each line has the following structure: XYplorer nn.nn.nnnn [yyyy-mm-dd hh.mm.ss] [S256 S256].zip ↑↑ ↑↑ ↑↑↑↑ ↑↑↑↑ ↑↑ ↑↑ ↑↑ ↑↑ ↑↑ ↑64× ↑64× so a ...
0
votes
1answer
25 views

7zip: compress and copy to destination folder

I am trying to do the following: command line compress a file from C:\TestFolder\file.txt (source location) and on the same command or bat file put that compressed file in (a destination folder) ...
0
votes
1answer
31 views

How to search for a file that is compressed on a external drive from my mac?

My hard drive went on my mac. I replaced it with a new hard drive. I was able to dump all the data from the damaged drive onto an external drive. The dump separates some of the files into word docs ...
0
votes
0answers
20 views

GPG with tar.gz at the same time without the full path being packed

I would like to compress and encrypt a folder: tar -cz "/path/to/the/folder/" | gpg --encrypt --passphrase "password" --recipient "mail@mail.mail" > "/destination/package.tar.gz.gpg" When I ...
1
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0answers
19 views

Video codec for simple animation? [migrated]

I am generating an animation in Matlab, composed of simple diagrams. The images are characterized by fine structures, strong contrasts and mostly discrete colors, e.g. there are few-pixels wide black ...
0
votes
0answers
21 views

LAME doesn't compress MP3 anymore

(I'm running Ubuntu 14.04) Until a while ago the following command used to work fine for compressing MP3 files: find . -iname '*.mp3' -exec sh -c 'lame -b 160 "$0" "$0"-160 && mv "$0"-160 ...
2
votes
0answers
25 views

Disable memory compression in Mac OS X for specific application?

Is there any way to disable the memory compression in Mac OS X for a specific application? I read how to disable it in general at Disable compressed memory in Mac OS 10.9 Mavericks? , but in my case ...
0
votes
1answer
23 views

How to compress an encrypted partition or drive in Windows?

Could someone let me know is there any effective way to compress an encrypted drive or partition in Windows to reduce its size ? Thanks
-1
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1answer
28 views

How can i compressed(winrar) a file using command prompt and the file name of the .rar is the same with the file

i have a autoback.bat file that will automatically backup my database and compress in using winrar application. the problem is i cannot create a rar file that is the same filename of my database. for ...
1
vote
0answers
26 views

Possible bug in 7zip - empty folders extract as empty files

I have a directory structure as follows: Main | |--empty_folder | |--folder | |--example.txt I'm zipping it using the .NET ZipFile.CreateFromDirectory method (but I doubt this has anything to ...
-3
votes
1answer
60 views

Why youtube compression algorithm doesn't work well for Minecraft videos?

Minecraft videos have very small entropy : I can play hours to minecraft online exchanging only tens or hundred MB of data with the server, this is an entropy upper bound for Minecraft videos. ...
0
votes
1answer
49 views

What happened to .gzip option in 7-zip?

I am not sure if this is just a coincident or not but I have recently upgraded my OS to Win 10. I noticed only now (after the upgrade) that the .gzip archive format is not available in 7-zip ...
0
votes
0answers
15 views

How to change context menu option for 7zip?

I work a lot with .gzip format and I am wondering if there is a way to change the default "Add to" format in the context from .zip to .gzip.
1
vote
1answer
34 views

how to achieve same compression in linux and windows

I have a example.jar file. I'm trying update a class file in the jar. when I'm packing the class file using jar or zip utility(command line-linux) I tried : jar uf my MyJarFile.jar ...
0
votes
0answers
5 views

Why am I encountering 'Error decoding stream footer' when decompressing using `pixz`?

I compressed a file using tar -pcv input_dir | pixz 8 -p8 > output.tar.xz. When I try to decompress or list the files using pixz -d and pixz -l i encounter the error Error decoding stream footer. ...
-1
votes
0answers
27 views

Strange model of zip split files

I have some zip splited files, with random sizes, and named as: file 1.zip file 2.zip file 3.zip.... I try unzip this files with the programs winzip, winrar and 7-zip, but when i click in the first ...
0
votes
1answer
15 views

decompress multiples pdf files without using tmp files?

I have more than 100.000 pdf files I want to decompress it, then recompress theme all in one archive file to save space. all i found is: ls | xargs -P 4 -n 1 -I {} qpdf --stream-data=uncompress {} ...
0
votes
2answers
26 views

To open lrzip-compressed in Debian 8.1

I downloaded the SageMath jessie package here but I cannot open it. I get the warning in ArchiveManager Could not open this file type There is no command installed for Tar archive (lrzip-compressed) ...
5
votes
1answer
311 views

How do I use Google data compression proxy on Firefox?

I am using GNU Icecat (GNU version of Mozilla Firefox) on Trisquel GNU/Linux. In order to minimize/optimize data usage while web surfing, I want to use google data compression proxy. So, How do I use ...
1
vote
1answer
28 views

rar - command line switch for exclude compress but store?

Assuming I have few files like : --- +Royi | +---1.txt +---2.txt +---3.Avi +---4.mp4 +---5.docx looking at : rar a -r -m1 Royi myArchive.rar This will shrink all ...
0
votes
0answers
44 views

Why is none of my Mac memory compressed?

I am constantly up against the 16GB physical memory barrier on my mac. I have looked in Activity Monitor and ZERO memory is compressed. I would like to have OS/X be aggressive in compressing - how ...
1
vote
1answer
56 views

Compress large CSV FIle? (500MB)

I have a CSV-File which is 500MB of size. I am searching for a way to compress is to it smallest possible size. I actually received the file back then in a ZIP-Folder which was only about 50MB of ...
0
votes
0answers
35 views

What are all parameters to get the highest compression ratio for animation from ffmpeg x265?

Ok. I'll use -crf 51 (-crf 61, -crf 10 or any other), -preset placebo, -keyint=-1 (only one keyframe in the start). -allow-non-conformance (I am not sure if this is work with libx265). -ref 16, ...
0
votes
1answer
50 views

How do I zip files with the same name?

I'm on a Mac OS X 10.10.4 I need this: Detecting files with the same name, but different extension. (aaa.ai, aaa.eps, aaa.pdf and bbb.ai, bbb,eps, bbb.pdf and so on) Compressing those with the same ...
0
votes
1answer
41 views

Which level of compression should I use a .iso file [duplicate]

I have a .iso file on my hard drive (on a windows 8 pc) and it is really big (something like 16 GB). I was trying to compress it (using 7-zip) so it could fit on a DVD-R. But when it finished ...
2
votes
2answers
77 views

How to compress extremely large file in place

I need to compress a 646.4GB file on a 1TB external HDD. This HDD currently has about 238.6GB free. However, since the straightforward compression methods create a new file, I'll not be able to ...
0
votes
4answers
94 views

How to open tar gz file created using tar piped to gzip

I wanted to generate a tar gz file with the highest compression level, and I followed the solution from http://superuser.com/a/546509/461740: tar cv /path/to/directory | gzip -9 > file.tar.gz ...
0
votes
1answer
42 views

.zip corrupted on Mac

I've got a .zip file of approx. 20GB. (20,497,570,063 bytes) I am trying to uncompress it but both Archive Utility and Terminal are failing to do so. Archive Utility is giving error 2 (no such file ...
0
votes
0answers
25 views

regex search compressed password protected files

I have a repository of a few million large text files. I need to regex search them on a regular basis. Because they are large, I use gzip to compress them and zgrep to search them. I have been asked ...
0
votes
0answers
73 views

How to recursively extract a zip bomb?

I downloaded the famous 42.zip zip bomb and was able to extract it in my computer without my system crashing. Then I realized that in order to see the effects of the bomb, I will need to recursively ...
2
votes
0answers
38 views

Unzip .gz file when line order is important

I am trying to unzip fastq.gz files and then analyze the sequencing data within them. However, later analysis is dependent on preservation of line (line 1 from zipped file must be line 1 in unzipped ...
0
votes
1answer
34 views

Unix gzip more than one file at once

I have come to the end of my research with unix:> I'm new with unix and its enviroment, so i need your help guys. Long story short, i have a housekeeping script, which runs daily/weekly (it doesnt ...
1
vote
1answer
129 views

“Compress contents to save disk space” option not available for one partition

One of the partitions on our Server 2003 R2 server recently ran out of free disk space. After freeing up a significant amount of free space (20 GB, which only corresponds to 1.37% of the partition - ...
0
votes
0answers
12 views

Will archiving little-used directories in my Dropbox folder increase the indexing speed?

I have 14336 files in my Dropbox directory. Many of these are in old projects that I don't touch any more, but that I like to keep around in case I need them. I know that Dropbox holds an index on ...
-1
votes
2answers
65 views

What kind of image compression causes this color banding? [closed]

I have two images. The first is before undergoing lossy compression: Picture #1: The second is after undergoing lossy compression: Can anyone explain to me what is going on here? How does this ...
0
votes
1answer
27 views

NTFS Compression on multiple folders

I have been tasked with compressing certain folders on a network drive. The drive is formatted NTFS on a Windows Server 2008 R2 machine. The folders to be backed up are all called "Backup", and are ...
1
vote
1answer
84 views

7zip Batch Compression for a specific file extension in different folders

I've already learn how to batch compress my files as-is with 7zip but I have something more complex need on this issue. Maybe I can explain my needs with this scenario; I have a backup folder of my ...
0
votes
1answer
31 views

No 'Compress this drive to save disk space box"

I have two external hard drives, both with NTFS, one of them allows me to compress it, the other doesn't, why? https://goo.gl/photos/AqV5V42dEY5N2o569 I deleted titanfall and bf4, freed up some ...
0
votes
1answer
41 views

Jpegtran made images bigger

I ran jpegtran on a bunch of images as such: $ jpegtran -copy none -optimize Most of them were reduced in size by a lot. But some of them actually increased in size. How can that be?
0
votes
1answer
70 views

Determining Cause of Unexpected Shutdown on Windows 8.1

I left my computer unattended a little over half an hour while it was compressing some files. I came back, and my computer had apparently shut off. I looked at the Event Logs, and it told me that The ...
0
votes
1answer
46 views

Windows 7 compressing doesn't reduce space [duplicate]

I used the compression method by windows 7 from the properties of a file but it doesn't seem to work. The folder that was around 42,6 Gb is now 42,5 Gb which means it only saved me 100 MB? Is there ...
0
votes
1answer
69 views

Gzip compression on Apache using .htaccess

As per http://gtmetrix.com/enable-gzip-compression.html i'm trying to enable gzip compression on apache webserver adding code mentioned below in .htaccess, but it's not working ; can you please ...
0
votes
0answers
28 views

“recompress” a 7z archive inline

I have a rather large (~500GB) 7-zip archive. I originally made it when I had more space available, and did so at rather fast, low-compression settings. Now things are tight, and I'd like to try and ...
2
votes
2answers
74 views

How to compress serveral, large, high entropy, but very similar files?

I have several big (as in: bigger than any dictionary, 100s of GBs) files. These files are very high entropy and compress very poorly. However these files are (as far as i can tell) almost completely ...
0
votes
1answer
42 views

Incorrect size of image file made with dd and gzip?

In the past I made a backup of a partially full partition with dd if=/dev/sda1 | gzip -5 > file.gz. Some time later, when a free space on partition was smaller I made an image file again with the ...
-1
votes
4answers
41 views

Why isn't it possible to Encrypt and Compress a Folder on Windows?

I read this blog which explains why this isn't possible but I can't seem to figure out the reason. I find the blog a little difficult to understand. Can someone please explain why it's not possible ...
0
votes
2answers
53 views

How to know the compression level of a PNG file and whether it is lossy?

Can I know whether a PNG file was compressed and how (at least, whether it was a lossless compression) in Windows? When I open the standard file properties dialog from the Windows Explorer, I see no ...
1
vote
2answers
107 views

What was the SquashFS compression method?

I've got some SquashFS files, and I'd like to know how they were compressed so that I can have a rough idea of how they would perform when mounted. The only binaries provided by the squashfs-tools ...
0
votes
1answer
28 views

Decompress files in subfolders to the same subfolder using 7-Zip

I have a set of subfolders with .gz files buried in them. I need to decompress the files and keep the directory structure the same. I have used for /f "usebackq" %i in (`dir *.gz /s/b`) do 7za x %i ...
2
votes
2answers
105 views

Which lossless image codec can achieve the highest compression ratio on photographs of buildings? [closed]

I was wondering which lossless image codec is best for compressing photographs* if we only care about final file size? * scanned negativs specifically Additionally does it make a difference if the ...