Compression decreases the size of data.

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36 views

TAR and compress a directory but skip compression on already compressed files

I want to TAR and compress a user's home directory as efficiently as possible. The problem is there are a lot of large and already compressed (gzip/bzip2) and hard-to compress files (binaries/data) in ...
1
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0answers
82 views

Archive Directory Using Zpaq

I am trying to setup a backup system for a server that I manage to improve upon the old system. I am choosing zpaq because it provided good compression with the old system using lrzip -z and because ...
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2answers
702 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 anymore....
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0answers
36 views

How to save compressed (batch processed) video files to the original folders using handbrake?

I use handbrake to compress/encode video files and I'm quite happy with the results. It gives me small file size with no quality loss. The problem is that when I batch convert multiple files from ...
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2answers
41 views

Edit executable file, instead of run, in Compressed Folder Tools

When I open a .zip file in Windows 10, and view it in its Compressed Folder Tools, I can open text files, Windows documents, etc. But for executable text files, like .bat or .js, the open option tries ...
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0answers
17 views

7zip File Compression Auto-Selection

When I'm zipping a folder hierarchy, I'd like 7zip to automatically detect whether a file in the folder tree is or is not already compressed, so that it automatically chooses whether to merely add an (...
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0answers
36 views

wget only new or updated files when the source files are compressed but the destination files are uncompressed

I would like to know how to wget files from a url which are stored with bz2 compression. However, I would like to only wget the new and updated files, relative to my destination, where the files are ...
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1answer
315 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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1answer
4k 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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3answers
1k views

Create multiple zip files that are not dependent on each other?

I want to compress a folder into multiple zip files of 50MB each but don't want them to be dependent on each other. When I use Winzip and use the split feature it creates one zip file and the others ...
0
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1answer
2k views

How do I compress a 200MB MOD video file?

My grandpa sends me this huge 200MB video file and asks me to compress it. I bet that there are many ways I can do this. For instance, just guessing some ideas: Use an online conversion tool (http://...
4
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1answer
28 views

Can compression of folder be undone when it comes to slow?

I know that compressing save disk space on my hard drive and I know that it is mutch slower for read a file. However I will compress the C:\Users folder. Personal files are stored on a SSD drive. ...
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2answers
2k 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 ...
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1answer
124 views

Best data compression format available [closed]

I'm sometimes sharing big files (1 GB, Visual Studio C++ Solution) over the internet, but I have very very low upload speed. So, I'm trying to compress my data into the smallest file as possible. I ...
0
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0answers
53 views

Why is Encase disk image smaller than used space on source HDD?

I am using a forensic disk imaging tool to make an Encase (E01) disk image of a 4TB hard drive. 3.19TB of space is actually used on this disk. The resultant disk image is 2.82TB in size. No ...
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2answers
56 views

Extract .tar.gz file that has files with .gz extension

Using this question I 'zipped' the folder with thousands of images on apache server. This apparently changed the files inside the folder itself and zipped the files. But that's not the issue atm. I ...
2
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0answers
58 views

Is there anyway to reduce bandwidth usage of Skype for business?

We use a lot of 'Skype for Business' (i.e. the new Microsoft Lync), that I use while consuming expensive roaming data. Was wondering, if there are options (similar to various VLC clients) that lead to ...
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1answer
79 views

Which files and folders are compressed when using compact.exe /CompactOS

I am thinking of using NTFS compression (LZNT1) on my SSD using Windows 7, but I was a little unsure as to which folders would be a good candidate. I was aware that Windows 10 has introduced new ...
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0answers
26 views

7zip is creating solid .zip files. Cannot add/remove/overwrite to .zip files ad-hoc

I'm using 7zip as an archive creation tool. .7z files may be created as solid or nonsolid files. .zip files are supposed to be inherently nonsolid. I have ~5GB of hierarchal folder/file structure ...
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8answers
25k views

Why doesn't ZIP Compression compress anything?

A 398MB directory was only compressed to 393MB using 7Z and Normal ZIP compression. Is this normal? If so, why do people continue to use ZIP on Windows?
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0answers
15 views

What is the relationship between dictionary size and compression ratio? [duplicate]

For dictionary based compression algorithms, would there be any real benefit to having a very large dictionary ? In what cases can a large dictionnary be usefull : small or larger files ? Thanks in ...
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0answers
48 views

How to extract PPmD archive data in Ubuntu?

So I have a file called ppmdData with no extension, then when I use the file command on it, it says it is a PPMD archive data. When I run 7z x secret, I get an unsupported method error. Can anyone ...
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1answer
69 views

Extract Y-channel of every I-frame from MPEG4 movie as loslessly as possible

I'm working on a video tracking experiment and got stuck with videos that are quite badly compressed with the MPEG4 DivX 5x/6x codec. I'm fairly new to image formats, codecs and compression, but I ...
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1answer
79 views

Extract multipart rar, deleting parts as they are extracted

I have a multipart rar of 80GB unpacked. I have 5GB of free space, and every part of the rar archive is 2GB. What I'm looking for is to extract one part, delete it, extract the next, and so on, as to ...
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1answer
97 views

How to send a delta (differential part) of a large binary file over the Internet?

I have sent a large (>1GB) binary file to a friend over a slow metered data plan and now I need to send the second version of the same file only slightly changed. I want to send only the delta/diff-ed ...
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0answers
15 views

Strategies To Reduce Compressed File Lookup Time With Pixz?

I have a PIXZ-compressed (level -9) tarball containing around 4000 files (ordered, like pages in a book): compressed size is ~670M. Currently I am programmatically accessing these files using the ...
3
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1answer
38 views

file splitting and compression in pipeline

So I have a massive file something like this... 1/20/2016,somerandomdata 1/20/2016,somerandomdata 1/20/2016,somerandomdata 1/20/2016,somerandomdata 1/21/2016,somerandomdata 1/21/2016,somerandomdata 1/...
28
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5answers
68k views

What is the maximum compression ratio of gzip?

What is the largest size a gzip (say 10kb for the sake of an example) can be decompressed to?
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1answer
259 views

How can I compress a jpg images for google insights optimisation

I m getting this error when tring to see the speed of my website in google page speed: Optimize images Properly formatting and compressing images can save many bytes of data. Optimize the following ...
74
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8answers
101k 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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1answer
27 views

Save-As from MS Office ignores 'compressed' setting

I have my complete data hard disk compressed (the Windows NTFS standard functionality), including root, all directories, and all files. When I open an Excel or Word file, and use Save-As, the new ...
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6answers
12k views

How to unpack a chrome theme?

How to unpack a packed chrome theme(*.crx)? Their FAQ states how to pack, but not how to unpack.
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5answers
8k views

Can Double Zipping Cause Problems?

I have a directory that I have been storing a ton of files in. Among the 10ish types of files there are also .zips of other directories. In my personal experience I vaguely remember issues when ...
180
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7answers
392k views

How to decompress a .bz2 file

I have a file as: filename.bz2 I need to decompress. I have tried the command: tar xvjf filename.tar.bz2, but it didn't work as the file is not a tar file. How do I decompress this file?
3
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1answer
73 views

Linux pv | gzip doesn't delete original file

I'm pretty new to unix so go easy. Normally gzip file replaces file with file.gz (which i'm guessing is: create file.gz then rm file). I have some rather large files I'm compressing and I like to ...
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2answers
361 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: ...
2
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3answers
165 views

How can I compress every 10 files in a folder as a separate zip file?

I'm on Windows 10 and trying to work it out with Winrar. The folder contains 500 files, I would like to compress every 10 of them as a separate zip/rar file and create 50 zip/rar files. Is there a ...
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6answers
10k views

How do I convert a Linux disk image into a sparse file?

I have a bunch of disk images, made with ddrescue, on an EXT partition, and I want to reduce their size without losing data, while still being mountable. How can I fill the empty space in the image's ...
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0answers
10 views

7zip - Encrypting and compressing each file in a folder while maintaining directory structure [duplicate]

Say I have a directory structure like this: - main folder - folder 1 - file 1.txt - folder 2 - folder 3 - file 2.txt - file 3.png - file 4.txt - file 5.jpg I'd like to ...
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0answers
102 views

What ffmpeg settings to get the best possible video resolution/framerate that my webcam is capable of?

I want to record the best possible video file (in terms of resolution/framerate/colors) from my webcam. Right now I am using this command: ffmpeg -f v4l2 -framerate 25 -video_size 640x480 -i /dev/...
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0answers
89 views

Missing all the options in the Send To menu

So I'm just trying to send a file to a compressed folder from Explorer. But for some reason the only option I have there is "Bluetooth device". Did some Googling, found a suggestion to check the C:\...
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0answers
178 views

System and compressed memory taking too much memory

I recently upgraded my windows 10 OS but having a new issue with this "System and compressed memory" its taking too much memory and i have never seen this types of process in my task manager its kind ...
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0answers
53 views

What's the default compression algorithm used by Windows's Compression tool?

I'm trying to find out some documentation which details out which compression algorithm (e.g. deflate, LZMA, BZip2) is used by Windows 10's Send to 'Compressed Folder' tool. Some people reported that ...
3
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3answers
619 views

Compressing compressed .tar.gz files deterministically

I want to perform a series of recompressions of compressed files to study their properties. At first, I tried simply recompressing .zip files in a loop: for f in $(seq 1 100) do zip $f.zip -9 -v $...
4
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2answers
4k views

Is it possible to compress a full file system on Linux?

On Windows I can use NTFS drive compression to save heaps of disk space; usually 30%, often much more. It also improves read and write speeds at the cost of higher CPU usage; which isn’t an argument ...
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0answers
25 views

How do I shrink the size of a Djvu file?

I'd like to upload on Wikimedia Commons a djvu file from the Internet Archive, but unfortunately its size is larger than 100 MB, so I cannot. I was thinking that I could derive a new file from it, ...
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3answers
4k views

What file compression application is the most space-efficient?

I have a bunch of directories that I want to keep, but I also want to clear out storage on my drive. What is the most efficient (in terms of compression ratio) compression application? I don't care ...
0
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2answers
106 views

what's the difference between “zip” and “compress” and “pack” ?

I saw article tile ——"Compress and uncompress files (zip files)" from Windows 7 document here. What's the difference between "zip" and "compress" and “pack”? Is it the same thing? I am so confused ...
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0answers
53 views

Convert and compress multiple tif (image) files into one PDF with OCR

I have found one old project that does exactly what I want! But it's broken somehow. Some crucial parts seems to be missing. It's a nightmare to configure. You can look at it here: http://...
0
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1answer
143 views

Unzip delete and unzip

I am having an issue with commad line unzip and am not sure how to correct this. I am unzipping a compressed file and it processes it correctly. If the zip file should have some files removed and it ...