Questions tagged [compression]

The re-encoding of a file or data into a form that uses fewer bits of information than the original data.

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23 views

Use gzip to uncompress svgz file: unknown suffix

I tried to uncompress a .svgz file using gzip, but encountered gzip: p1.svgz: unknown suffix -- ignored. $ gzip -d p1.svgz gzip: p1.svgz: unknown suffix -- ignored I added the suffix .gz to the ....
10
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1answer
3k views

Can I turn off swap and/or memory compression on macOS 10.12, Sierra?

Is there a way with macOS 10.12, Sierra, to safely turn off compressed memory? And is there a way to turn off safely swap? This was possible on macOS 10.9 and macOS 10.10. Although it sometimes ...
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3answers
2k views

macOS equivalent to the Windows “Compress file/folder content on disk to save space” option

Windows has a useful feature where files can be transparently compressed/decompressed on the fly. This is activated by right-clicking on a File, directory or Disk, selecting Properties and then ...
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0answers
43 views

Why does Image Capture scan tiff files with different compression formats?

I'm scanning some old family photos using Image Capture. I want a lossless image using TIFF and LZW compression. What I'm seeing, thanks to the tiffutil -info <file> command, is that the .tiff ...
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2answers
3k views

APFS - how do I enable transparent compression

How do i enable transparent filesystem compression on any APFS volume? Or check if it is already enabled? I am expecting something similiar to NTFS compressed attribute. According to Wiki it should ...
80
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7answers
114k views

How can I unpack .7z files via MacOS terminal?

Looking to unpack a bunch of files.7z via terminal. Is there a command-line tool built in, available or I shall install an application that comes with a graphical interface?
2
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0answers
82 views

What is the full name for LZVN, the compression algorithm?

The LZVN algorithm, like the better-known LZFSE, is introduced in macOS 10.9 for decmpfs. It was discovered in 2014 as a kernelcache compressor before the official WWDC 2016 release of LZFSE, which ...
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1answer
3k views

Does OSX 10.10.4 support LZMA compression at the individual file level (not tar files)?

From the command line, I would like to compress some database dumps using the LZMA algorithm. And, OSX adds XZ support (written in October of last year), claims " It turns out the XZ support in OS X ...
2
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1answer
44 views

Is it safe or beneficial to compress a .photoslibrary file?

I am trying to create external backups of all my digital data in case something bad were to happen. Is it safe, or even beneficial, to compress a .photoslibrary file to store on an external device for ...
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0answers
103 views

Batch compress contents within a folder using Mac Automator

I've seen an automator service that can zip multiple folders into separate zip files: Batch compress multiple folders into individual zip files Can this be modified to enter the folder, compress the ...
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1answer
116 views

How to convert non-utf8 encoding to utf-8 encoding during unzip?

I have the same problem which described here. The only difference is I need to do this in MacOS. Basically, all files are encoded in non-utf8 and zipped on Windows. When I unzip it on MacOS, they ...
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3answers
2k views

Convert a number of zip file to rar?

Any suggestion of how to convert tens of zip files to rar format? App or command line tool are welcome.
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3answers
19k views

Why do the photos on my iPhone 7 seem to be losing quality?

The photo quality is my iPhone 7 is very low. I found out that this may be because I switched on “iCloud Photo Library” a few months earlier, and “Optimize IPhone Store” was selected. Does doing so ...
22
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4answers
14k views

Why are so many Mac downloads a .dmg just that contains a single .pkg?

I've noticed that many downloads are a dmg (disk image) that contains a single pkg file (installation package). Usually the pkg seems to be already compressed since the dmg doesn't reduce the file ...
2
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3answers
2k views

Can .zip folders created using Windows XP Pro be opened and extracted on Mac without any additional software?

I am a Windows user, and I would like to send a compressed archive/folder to my colleague who is a Mac user. I do not want him to have to download any additional software to open and extract it. Can ...
11
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3answers
7k views

Tell macOS to only use swap and compressed memory when really needed (macOS 10.14 Mojave)

As disabling swap and/or compressing memory is not recommended and also not a stable option after 10.9 Mavericks (despite the vm setting exists), I'm doomed after few days of running my Mac with my ...
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4answers
4k views

How to extract an .ace compressed file?

Is there a way to open .ace compressed file on macOS? I tried searching for solutions but haven't come across any method to extract it yet.
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2answers
6k views

What is wrong with “compress” option?

In finder, I can cntrl + click on a file and click "compress"... Sometimes. It seems that randomly the option just won't show up and I have to open a new finder window, or duplicate the folder first, ...
1
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1answer
361 views

Compressed hidden files are not hidden anymore when uncompressing on Windows

When I zip hidden files and folder and unzip on a Windows PC, they do not remain hidden. I tried to hide them with dot and also with the command chflags hidden. Is there anything I can do? It happens ...
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1answer
569 views

A script to shrink and compress DMG disk images does not seem to work well in my scenario

I'm trying to resize the *.dmg of my MAC OS X installation file because I have only DVD of 4.7 GB and not dual layer disks,at the moment. The problem is that the dmg file is almost 7 GB large and I ...
2
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2answers
180 views

How to decompress and run .app?

I'm trying to execute an AppleScript .app thats compressed. unzip -p file.app.zip | open - or open < $(unzip -p file.app.zip) Is this possible?
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3answers
204 views

Is it okay to compress application files? (Especially licensed applications)

I have attempted to research this but given the fact that applications exist to compress other files, I've found it difficult to learn about compressing applications themselves. I presume its okay to ...
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3answers
50k views

How can I make a PDF document smaller?

Here's my problem, I have a PDF document 583KB, and I want to make it under 500KB so I can upload it. What should I do?
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1answer
167 views
2
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1answer
1k views

How to unzip .xz

How can I unzip a .xz file? Archive utility failed. Is there an app that I should get to do it? (Mac Pro, OS X Yosemite 10.10.5)
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2answers
125 views

Compression / archival utility which stores the most metadata?

I recently did a backup of a FAT32 disk which contained a lot of diverse data. It contains many media files, many big binary files, and as usual with FAT32, it has all kinds of odd (but potentially ...
17
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4answers
8k views

Creating an automated HFS+ compressed folder

I would like to set up an automated way for archiving files in OS X Lion. By archiving I mean using HFS+ compression feature on a specific folder, and make every file that I move into this folder ...
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1answer
1k views

Extract HFS+/HFSX volume from dmg file

Dmg file contains a volume with identifier Apple_HFS, which is compressed with various methods (zlib, bz2, etc.), how can I extract a raw, uncompressed HFS volume from DMG file? Right now, it cannot ...
8
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1answer
5k views

Large zip files created in OS X cannot be opened in Windows

When I compress a large directory in OS X, like 5-6 GB the resulting archive cannot be browsed in Windows / Total Commander. It hangs the app and stays at 100% cpu usage, like its trying to extract it ...
7
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1answer
2k views

How do I transparently compress a directory?

I'd like to enable HFS+ compression for a directory, applying it to both the existing files in that directory and newly copied files. I expect to be able to read and write the contents of that ...
4
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1answer
6k views

Can SquashFS filesystems work with macOS El Capitan?

I am converting some .tar.gz to SquashFS (using squashfs from homebrew) using xz compression because I want to be able to mount the archives and read the content without extrating and also because the ...
0
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2answers
59 views

Compress attachments in received emails

I regularly receive emails with very large attachments (uncompressed scans, photos, videos, etc.). Obviously, the sender could have done me a favor by compressing the files before sharing. But not ...
2
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0answers
175 views

Can I turn off memory compression for one specific app?

I am using MATLAB on my Mac. Well, MATLAB is running well but not fast -- while there are plenty of free memory, my Mac still compresses MATLAB's memory - from ~2GB to ~600MB -- not to mention the ...
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2answers
469 views

compress Long size file into multiple limited size xz file

I have files of 28GB size. I want to compress using .xz LZMA, with .xz chuncks of 1G (1024MB) size files... MyFile.vdi -> MyFile00.xz, MyFile01.xz, MyFile02.xz... How do it in macOS? EDIT sh-3....
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2answers
4k views

How to compress iPhone QuickTime screen recording's file size?

I've recorded my iPhone screen through QuickTime on my MacBook and made several recordings already. Unfortunately, the resulting files are too large. They get saved in .MOV format, and 10 mins takes ...
1
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1answer
56 views

Breaking pdf to various images, compress, and recombine

I want to save each page of a PDF file as separate image, compress them, and recombine back as PDF. Some PDF files I often use are strangely large in size. I mean, some 100 pages but some 200M. I ...
1
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1answer
4k views

compress jpeg images from terminal [duplicate]

I am looking for a way to compress jpeg images on a Mac from Terminal. Basically, a library like pngquant, except it is for jpeg format. Are you aware of a software that does that?
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0answers
40 views

What are those “._<filename>” files show in tar verbose output, but are not in the untarred directory? [duplicate]

Some hidden files appear in the verbose output of tar, but then do not exist in the directory where the tar output is deposited. I am surprised by this because I thought working in Terminal command ...
3
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1answer
4k views

Create tar archive with xz compression?

I'd like to create a tarball using the xz compression tool. According to google, as of 10.10 there is an undocumented "--xz" switch for tar but I can't get it to work. On linux there is a "-J" switch ...
1
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1answer
621 views

Multithreaded compression in xz on macos

Is it possible to use the multithreaded compression built into xz 5.2+ on macos? Currently using homebrew xz 5.2.3 on macos 10.12.3 with a hyperthreaded quadcore cpu and no matter my setting for ...
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2answers
533 views

Compress multiple files in different folders

Could someone help me with compressing thousands of files? I have a lot of folders and a lot of files in these folders, i would like to know if it's possible to compress each file separately. Foe ...
1
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1answer
44 views

How can I de-compress a source file on my basic MacBookAir (macOS Sierra Version 10.12.2)

I've downloaded the source file from https://arxiv.org/format/1610.01410v2 How can I decompress it to obtain the plain text (say, in a TextEdit file)? The file I downloaded is designated 1610....
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3answers
1k views

Terminal - Is the built in zip command lossy?

I'm using BASH in the terminal on Yosemite. Is the zip command lossy? I'm using it like this zip -er ./output.zip ./input -e encrypt -r recurse I am trying to avoid lossy compression when ...
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1answer
192 views

Preferred sources/methods for VirtualBox images on macOS 10.12?

I have a 2016 MacBook Pro running macOS 10.12 and I want to run a Linux VM such as Mint using VirtualBox. I am looking for best practices or official/recommended sources for an image that is packaged ...
2
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1answer
2k views

Why does .tar.gz automatically extract the GZip archive when I download it in Safari?

I downloaded a .tar.gz archive backup of a website. Every time I download it, when I click the magnifying glass in Safari Downloads, it takes me to the file, but it's now just a .tar, and so is ...
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2answers
3k views

Compress folders with lots of duplicate files

I have a hierarchy of folders which contain lots of duplicates files (it's a series of versions of a LaTeX document, and while the evolved a lot, many of the figures are identical in multiple versions)...
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1answer
105 views

How is the Compressed Mem column in Activity Monitor calculated?

Say we have something like Process Name Memory Compressed Mem Firefox 2.60 GB 1 GB What do the figures mean? Is it: 1GB is compressed and we don't know how much it's compressed by so ...
6
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2answers
739 views

Will Time Machine store the same data twice in this situation?

I had 80 GB of movies on my internal HDD. Time Machine backed them up to an external HDD, along with everything else on my drive. I then moved those movies to another external HDD (which is not being ...
2
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1answer
403 views

Do Apple Lossless tracks remain lossless when sent via Airplay to a 4th gen Apple TV?

This question, from 2012, asks whether there is loss in the signal quality of an Apple-Lossless-encoded file when transmitted from a Macbook to an Airport Express. I am wondering whether things are ...
3
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3answers
14k views

What does error “the Classic Environment is no longer supported” mean?

I created a .app file that is 303KB on disk. When I right click it and press Compress... I end up getting a 8.4MB .zip archive. I tried sending the .app via email to myself and compressing it on ...