Compression decreases the size of data.

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29 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 ...
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2answers
56 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 ...
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4answers
80 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 ...
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1answer
30 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 ...
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19 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 ...
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55 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 ...
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0answers
31 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 ...
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1answer
21 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 ...
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33 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 - ...
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11 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 ...
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2answers
56 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 ...
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19 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 ...
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1answer
45 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 ...
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1answer
12 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 ...
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1answer
26 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?
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39 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 ...
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40 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 ...
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37 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 ...
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16 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 ...
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2answers
65 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 ...
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1answer
35 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 ...
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4answers
39 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 ...
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45 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 ...
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2answers
55 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 ...
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1answer
25 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 ...
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2answers
59 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 ...
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50 views

How can I list the contents of an lrzip file without extracting from the Linux terminal?

How can I list the contents of a lrzip file created via lrztar without extracting it?
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1answer
45 views

Excel conditional drop down lists causing massive file size

I have an excel file which relies heavily on data validation. There are about 20 drop down lists per row. One column has a 35 formatting conditions. One column is a conditional drop down list (using ...
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1answer
34 views

How to recursively compress subdirectory's files with password

I need to recursively compress subdirectory's files with password and then delete the uncompressed file in bash file. There are zip files and other files. I don't want to compress zip files again. I ...
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1answer
40 views

Does unzipping a file on a remote server download the files back to my local?

I need to copy a high number of files to a remote windows server. I am connecting to it via VPN and then browsing to the remote folder in Windows Explorer. Problem is uploading is really slow, ...
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32 views

How to create a highly compress self extracting archive with 7zip or winrar?

I have downloaded a highly compressed call of duty modern warfare highly compressed 99 mb self extracting 7 zip archive .after extraction it becomes 6.35 gb how they compressed these things .i know ...
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40 views

Losing storage space on Windows 8.1 by compressing and decompressing the disk [duplicate]

At first I thought if I compress the disk, then I would get extra space. However, after doing the compression I lost 2.5GB. Then, I decompress the whole disk to regain the lost 2.5GB but I lost 1GB ...
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1answer
50 views

I can't get compress.exe to produce anything

I'm trying to emulate the Windows Send to/Compressed (zipped) folder function using the Microsoft tool compress.exe, included as part of the Windows Server 2003 Resource Kit. It might not be possible ...
2
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1answer
42 views

PNG or JPEG for an X-Ray without visible artifacts

A past paper question from a Multimedia Systems exam: If you had an X-Ray photograph of a leg which might be broken, which would give better compression before artifacts were visible, and which ...
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117 views

FFMPEG / libx264: How to specify a variable frame rate but with a maximum?

Instead of providing a fixed frame rate to FFMPEG/libx264 (-r/-framerate), I would like to specify a variable frame rate with a MAXIMUM value, and allow libx264 to down the frame rate as it sees fit. ...
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3answers
33 views

Is it better to compress all data or compressed directories?

I'm archiving some projects, let's say each of them has own directory: projects |- project-1 |- project-2 |- project-3 I started compressing them as following: ==== SITUATION 1 ==== projects ...
2
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2answers
66 views

Container with in-built compression, which automatically adjust its size

I try to find an efficient way of rsyncing contents of an ext4 file system as a part of a regular backup, yet I consider a decent compression and a minimal required space. I can just use plain rsync ...
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0answers
77 views

Uncompressing files, compact'ed on Windows 10

I'm testing Windows 10 and one very interesting thing I found is new switches for compact: Displays or alters the compression of files on NTFS partitions. COMPACT [/C | /U] [/S[:dir]] [/A] [/I] [/F] ...
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1answer
127 views

ffmpeg: Highest quality 50i to 50p conversion, comparable to Adobe Premiere

I have 50i footage (more specifically tagged as 25 fps but does contain movement on the secondary fields). I am able to get pretty good quality conversion to 50p from Adobe Premiere by simply ...
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41 views

“Size on disk” column missing in Windows Explorer?

I decided to use the "compress this drive to save space" option on my backup drive, which simply houses a Windows Server Backup. I learned that when viewing file properies for files on a drive using ...
2
votes
1answer
57 views

Batch command to archive folders with content using WinRaR

I have lot of folders in the root "C:\Test\Archiv\" (more than 1000). To be more specific, I get one every hour. They are named as following : ay %year% m %month% d %day% h%hour% In each folders are ...
2
votes
1answer
77 views

7zip - Command Line: how to set output path?

I want to compress all HTM files in D:\HTM\ to an archive called comp.7z which is created in D:\HTM\ directory, so I do the following: 7z a -o "D:\HTM" comp.7z "D:\HTM" and get an error, exactly as ...
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1answer
22 views

Winrar self extracting SFX fail to launch

I created an SFX file (to unzip and launch a program directly) with Winrar which is supposed to be installed in a TEMP folder. I specified to launch "bin/myprogram.exe" after extraction. When I ...
0
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1answer
68 views

Winrar command line compression ratio

I have a Winrar command line that look like this: "c:\Program Files\WinRAR\WinRAR.exe" a -afrar -s -m5 "e:\output.rar" "e:\foldertozip" The folder that I am compress by default is 9.08MB. The ...
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How can compressed archives like .RAR be repaired?

I'm interested to know how WinRAR and 7-zip repairs archives but unfortunately I couldn't find any description about this process.So I'm here to ask: How does WinRAR or 7-zip repairing process work? ...
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45 views

How to create a zip file with files in FAT format on Linux

I have to create a zip file (with no compression). I want the files in the zip to be in FAT format. That is, If i use zipinfo command, I should get the following: ... -rw-a-- 2.0 fat ...
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28 views

accessing files directly from SFX archive

Similar questions have been asked on this forum, but not identical, so I am sorry if this is a bit redundant. I have made a "portable" application. I used WINRar to create an SFX self-extracting ...
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27 views

Why does performing OCR in Adobe create a much larger document?

I'm using Adobe Acrobat Pro XI on Macintosh OS X Yosemite and I've noticed that doing OCR sometimes creates a much larger document. For example, I scanned a four page document and got a 458K ...
2
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1answer
67 views

Slight file content difference due to LZW compression

In order to test if LZW compression is truly lossless I did the following: I created a master uncompressed TIFF file. Created an LZW compressed version of it Saved that compressed TIFF back into an ...
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42 views

Stop Compression: Google Drive Videos?

Is it possible to stop the compression of Google Drive videos? I uploaded an 18.4MB video in mp4, that was already compressed, and google drive added further compression, resulting in a block effect ...