Compression decreases the size of data.

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25 views

Should I archive old folders

I have many folders on my hard drives that contain many media files and logs for old websites I have created for clients that I rarely ever access now. I want to know aside from compressing them what ...
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1answer
35 views

Why this scanned book image has no background?

If you save this image on your desktop, you see it's background color as your desktop color. If you open it with Adobe Photoshop, its background id checkered which means it has no background. It's ...
5
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3answers
310 views

Unix/Linux program that can handle all popular compression/archiving formats (e.g.tar, gzip, bzip2, zip)?

I sometimes get confused by the varying command line options I need to run common Unix archiving and compression software (e.g. gzip, bzip2, zip, tar). Is there a program out there that can just Do ...
0
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1answer
28 views

Uncompress bz2 file from command line on Windows

Is there any tool in the Windows command line that allows me to do this? Otherwise, is there any light and portable application that will allow me to? Related question, can I rename .bz2 extension to ...
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3answers
1k views

How to optimize ZIP files for size? [closed]

I have a ZIP file (created by Info-ZIP on Linux) and I want to make it as small as possible. I have lots of CPU time to burn on the recompression. I already know advzip, and it managed to reduce the ...
0
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5answers
25k views

Can I compress a RAR file again to reduce its size?

I had a 326 MB iso file that I compressed using WinRAR, with the best compression method. It got compressed to 144 MB. I want to compress more and want it to be limited to something around 22 MB. ...
0
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1answer
49 views

Does copying files via MTP over USB compress them?

I'm trying to backup my phone to a computer running Ubuntu 14.04 LTS, and I noticed that one of my backup images looked noticeably more pixelated, even when viewed at the same size as my phone screen. ...
0
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1answer
1k views

Can't view files from within WinRar (Win7 x64)

I have an issue with WinRar (64 bit version) on Windows 7 (x64) that is similar to the one described in another open question on this website Link to the same issue on this site (unanswered) However, ...
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2answers
74 views

Is Gzip supposed to honor original filename during decompress?

This question stems from a Crypto++ library question on Stack Overflow: How to add filename to archive if compressing using Gzip class?. Gzip, as specified in RFC 1952 has an optional field for the ...
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3answers
136 views

How to automate Adobe Acrobat XI Standard to re-compress a lot of PDFs?

I've about 15 gigabyte of PDFs scanned with an old version of Adobe Acrobat that are huge. Adobe Acrobat XI Standard that comes with my new scanner has an option to (it seems lossless) recompress ...
2
votes
1answer
75 views

Samsung 850 Pro SSD compression

I intend on buying the Samsung 850 Pro SSD, to use as an external drive via USB and I am wondering if it uses any kind of compression, like SandForce based SSD drives? I am fairly obsessive about data ...
0
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1answer
153 views

reducing the size of PDF file of scanned images

I downloaded this PDF file from a website which is 350 KB in size with 20 pages. All pages are scanned images. I extracted the images using Adobe Acrobat Pro which are 1.32 MB in size collectively ...
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2answers
951 views

Avoiding extreme fragmentation of compressed system images on NTFS

Problem explanation I'm storing windows disk images created with wbadmin on NTFS drive, and I found compressing then with NTFS compression gives 1.5-2× space conservation, still giving full ...
0
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1answer
65 views

How to batch compress sub subfolders?

I'm on Windows Server 2012 R2. I have a directory that looks like this: Folder01 Subfolder 1 File1 File2 File3 Subfolder 2 File1 File2 Subfolder 3 ...
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1answer
39 views

is it safe to compress the File History folder?

Is it safe to compress the File History folder in Windows 8? Mine has grown rather big and a lot of the files types would compress well. However, I dont see any information on compressing it. It ...
0
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1answer
106 views

Is there a way to compress folders individually using 7zip on a large collection of folders?

How can 260 folders be zipped individually using 7zip with a single command? The person who originally asked this question voluntarily deleted the post. Since it was an interesting task, I ...
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2answers
65 views

7Zip Zipping up directories

I want to use 7 zip to compress and archive folders but I want it to exclude existing .7z files if they exist and not duplicate them with a .7z.7z ext I found this but it duplicates the already zipped ...
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0answers
21 views

General-purpose program for RLE compression

We have to deal with very large columnar files with fixed-size data and lots of padding bytes coming from mainframe. I would like to evaluate different compression techniques and their impact on ...
119
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6answers
14k views

How is PNG lossless given that it has a compression parameter?

PNG files are said to use lossless compression. However, whenever I am in an image editor, such as GIMP and try to save an image as a PNG file, it asks for the compression parameter, which ranges ...
0
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2answers
59 views

Best format for compression of large amount of small files

I tried to use .rar and I get a great rate of compression. However it take a lot of time to show the folder structure when I open the .rar file (tried different programs), it looks it is needed to ...
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3answers
247 views

Do more compressed PNG images take longer to load?

When I create PNG files with very small disk size, I tend to wonder if the file size becomes less important than the time viewers would need to decompress the image. Technically that would be trivial ...
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0answers
11 views

SASS e images not loaded

I have used webasset and cssmin on a python static site generator to merge 4 css files into a one compressed file. The individual CSS files when referenced individually does contribute to a fully ...
4
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1answer
3k views

tar/bz2 compress a file removing uncompressed original

Is there any way to turn a directory called dir1 into dir1.tar.bz2 without keeping the original? I need to save space and want to compress some large files but don't have enough room to keep a ...
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4answers
425 views

How to batch compress images with Imagemagick or similar command or program in Linux

I recently learned about the convert command from imagemagick which I have used to compress many pictures that I have for personal use, and for a blog that I have. In my experience, Imagemagick is the ...
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votes
4answers
256 views

Is it faster to compress files before copying? [duplicate]

I have around 80 GB of data I need copy to an external hard drive. Would it be faster to compress all the files first and then copy over? Or would the time it takes to compress and decompress take ...
3
votes
1answer
168 views

How to dump and compress MySQL database in Windows only using command line

Is it possible to backup and compress just like in Linux: mysqldump --all-databases | lzma > all.sql.gz I only have smb:// and cmd.exe access via winexe, so no GUI (remote desktop is not enabled, ...
2
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4answers
3k views

How to hardcode subtitles into an AVI without loss of quality

I am using a program to hardcode subs into an AVI file. The problem is that is recompresses the video using a codec. I don't see why this is necessary and causes a noticeable loss of quality. Is there ...
0
votes
3answers
1k views

How to reduce the size of windows OS Iso file?

I have an Iso file of windows 8.1 pro with December '14 updates. The problem is the file is too big to be burned on a normal 4.7GB DVD , its around 4.8. Now is it possible to remove a few updates so ...
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0answers
78 views

Pacmd dynamic range compression Ubuntu 14.04

I used the answer at the link below to successfully set Dynamic Range Compression on my Ubuntu media box running Ubuntu 14.04 (SteamOS session, so no Ubuntu desktop session available). Realtime sound ...
47
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8answers
54k views

What’s a good way to extract .rar files on the Mac? [closed]

Anything built-in? (E.g. command line tools.) Any well-regarded software? Update: I like The Unarchiver, but vote up your favourite, or add it as an answer if it isn’t there.
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0answers
20 views

LZA Compressor Directory

I am trying to use LZA to compress my directories (No sub folders) Whenever I use it however it automatically creates the archive within an additional folder! Example: I am using a folder called ...
0
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0answers
84 views

How to modify files within mszip (cab) executable?

I can list and extract certain executable contents using 7z. It seems to be using standard compression methods. Path = test.exe Type = Cab Method = MSZip How can I modify files inside that ...
4
votes
4answers
4k views

Recursively unzip files where they reside, then delete the archives

I goofed up a setting on the backup software I use. Normally I would have the files from a network share get loaded into a spare drive, compressed into zip folders, then sent off to the offsite hub. ...
10
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4answers
18k views

How to obtain maximum compression with .tar.gz? [duplicate]

The way i understand the use of tar + gzip is that tar is normally used to consolidate a grouping of files into a single file, then gzip is used to compress that file. I recently learned that tar can ...
1
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2answers
472 views

Force all files in a NTFS compressed folder to automatically compress [Windows]

Is it possible to keep all the files within a NTFS-compressed folder compressed? For example, if I have a compressed a folder using NTFS compression, it will compress all the files inside the folder ...
1
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1answer
2k views

Extracting a tar.gz file returns, “This does not look like a tar archive.”

I have a tar.gz file and I want to extract it using terminal. I used following commands: tar tvzf ldtp_3.5.0.orig.tar.gz and tar -xvzf ldtp_3.5.0.orig.tar.gz. However, I get the same result for both ...
0
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2answers
470 views

How to update a TAR/Gzip archive

I have compressed a folder using tar like this: tar cvfz folder.tar.gz folder/ Now, say I have changed some of the files in that folder, added some and removed some. And now I want to update my ...
0
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1answer
32 views

Is it possible to perform Deduplication recursively?

If anybody is familiar with the concept of Deduplication (If not,read link on wikipedia) http://en.wikipedia.org/wiki/Data_deduplication Is it possible to perform Deduplication recursively i.e. ...
1
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2answers
3k views

How to extract multipart rar with missing parts?

I have a multipart .rar archive containing a single .tar.gz file inside it (don't ask why, that is just how it was made). I am missing a few of the parts, but do have the first part. I would like to ...
0
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0answers
153 views

How do I access gzip-compressed data from a PowerShell Invoke-WebRequest command, when the “Accept-Encoding: gzip” header is set?

I'm learning about response compression in IIS and I'm testing my configuration with various tools. It appears that several of these tools either auto-decompress the response, or always send the ...
0
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0answers
44 views

Linux equivalent settings for 7zip

I'd like to use the same settings as below (Win7) on Linux to compress files, but I fail to get equal compression results, for which I blame myself not correctly using 7za. So far, I have 7za a ...
12
votes
4answers
2k views

Why is a FLAC encoded from a decoded MP3 bigger than the MP3?

To be more precise than in the title, suppose I have a MP3 file that is 320 kbps. If I decompress it, then logically, all the data except for roughly 320 kilobits out of each second of audio should be ...
6
votes
5answers
21k views

Reduce .wav file size

I am required by a distance education language course to record some audio and submit it. However, they are being absolutely unreasonable. I am only allowed to attach a file that is 5mb while my ...
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votes
1answer
57 views

How is this RAR archive able to achieve such a good compression ratio?

The RAR archive found here (direct download) contains a single AVI video file which is 42MB in size. The RAR archive is only 500KB. How can the archive achieve such a high compression ratio?
0
votes
0answers
36 views

Changes in level of compression between different versions?

I used the save function with xz compression as in save(a, b, file = "c.RData", compress="xz") This produced a file of different size on my disk (11589212 vs. 1162284 bytes) switching from R.3.1.1 ...
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4answers
742 views

Finding out what a file is

I have a compressed file but I don't know what it's compressed with. The extension doesn't give any clue. How can I find out what it is?
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1answer
103 views

tar reverse of '--to-command', or: compressing tar entries individually, or: tar with plenty of large files

I would like to create tar gzip archive, but do it the reverse manner of what is most commonly done -- have the files in the archive be compressed individually rather than compress the entire archive: ...
90
votes
4answers
183k views

How to decompress a .bz2 file

I have a file as: filename.bz2, but I can't figure out how to decompress it. I tried several methods, none of them seems work. I have tried the command: tar xvjf filename.tar.bz2, but it didn't work ...
3
votes
3answers
4k views

Between xz, gzip, and bzip2, which compression algorithim is the most efficient?

Between xz, gzip, and bzip2, which compression algorithm gives the smallest file size and fastest speed when compressing fairly large tarballs?
2
votes
4answers
178 views

What other archive formats save Date Created and Date Accessed?

7-Zip on Windows will save the Date Created and Date Accessed when compressing a .zip file, however it does not do this for its (referring to 7-Zip) native .7z format. Any Unix-based formats are ...