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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57
votes
7answers
72k 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?
25
votes
4answers
36k views

How do I create a DMG file from a directory?

I'm trying to add a few files into a dmg. How do I create a DMG file from a directory?
21
votes
4answers
12k 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 ...
16
votes
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 ...
14
votes
4answers
3k views

Tools to compress and encrypt files

I want to compress several files and encrypt them with a password if possible. Are there any build-in tools in Mac OS that provide such functionality? If not, can you recommend me a (freeware) ...
14
votes
2answers
3k views

why does OSX add extra '._<filename>' when I tar a directory?

I'd just like to know why if I "tar -czf" a file/directory, osx adds a: ._ for each file? I see these when I untar in linux. Or when I work with the uncompressed project in eclipse as it doesn't ...
8
votes
0answers
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 ...
7
votes
3answers
49k 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?
7
votes
3answers
4k 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 ...
7
votes
1answer
3k 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 ...
6
votes
2answers
3k views

How to zip from terminal without creating folder structure of path to folder?

It is possible to zip a target folder with encryption by the terminal command zip -er ~/Desktop/myzippedfolder.zip ~/Documents/myfolder/ However, the contents of myzippedfolder will be a folder ...
6
votes
2answers
3k views

Options on a Mac for a writable, compressed file system?

I have a SSD drive on my MacBook Pro and I'm constantly running on out of disk space because I need to install and run multiple virtual machines (Linux, Windows etc) on my Mac. Is there a way to mount ...
6
votes
2answers
708 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 ...
6
votes
1answer
13k views

Can I change compression settings on built-in archive utility?

I have a bunch of files I want to compress to stick in my dropbox account (as a single archive file.) When I select all the files in Finder and right click, I get the choice to "compress", which does ...
5
votes
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.
5
votes
2answers
541 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 ...
5
votes
3answers
6k 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 ...
5
votes
1answer
1k 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
votes
1answer
2k views

Software to losslessly optimize batches of image files

I frequently work with large numbers of image files to be used in websites. I'm currently using Photoshop's 'Save for Web' tool to find the most efficient way to compress images, but that takes some ...
4
votes
1answer
336 views

iPhoto files compressed in Time Capsule. Where is the original size?

My 8 year old iMac died some days ago. Fortunately, I have everything backed up on my Time Capsule. I just tried to get my photos from iPhoto off it, but realized that all my shots have been ...
3
votes
4answers
3k 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.
3
votes
1answer
3k 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 ...
3
votes
3answers
9k views

Create a zip file using an Automator Service

I am trying to create a service in Automator in Mac OS X Mountain Lion. The command that I want to use is as follows: zip zip-file.zip "$@" And here is a screen capture of what I did: It works. But ...
3
votes
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 ...
3
votes
2answers
1k 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 ...
3
votes
1answer
1k views

Problem with corrupt .rar file

I have a big file compressed in split .rar archives. There are 68 archives named .rar, .r01, .r02, etc., annd the problem is that .r36 is corrupted resulting in an Unexpected end of archive. I've ...
3
votes
1answer
16k views

Does the iPhone compress emailed videos?

When you open a video in the Photos app and choose to send it via email, does the video get compressed, or is it sent using the same resolution it was shot in? I'm mainly wondering about the iPhone 4....
3
votes
1answer
5k 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 ...
2
votes
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 ...
2
votes
3answers
2k views

Why are MP3 files not noticeably compressed by the compression tools within Lion?

I clicked the 'Compress xxx' option in the popup menu in order to compress a folder of MP3 files, but the result was a .zip file that is almost the same size as before compressing; it seemed to only ...
2
votes
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 ...
2
votes
3answers
140 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 ...
2
votes
2answers
1k views

I need to compress a PDF to 5 mb (at most, but best exactly)

Is there any way to compress a PDF (with the preview / iOS default software) to a certain size in mb (in my case as close as possible under or equal 5 mb)? The actual size right now is (6 scanned ...
2
votes
1answer
572 views

Is there a way for me to open a .xdi file?

I have on my computer a file that as been compress with the .xdi extension. Is there a way for me on my Mac OS X to open it?
2
votes
3answers
1k 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 ...
2
votes
1answer
2k views

Is Mac OS X's Compress a “standard” zip?

When I submit my research papers to an online review system, I prefer to upload all files (manuscript, figures, etc) by a single zip file, so that the review system can unzip the file. Otherwise, I ...
2
votes
1answer
323 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 ...
2
votes
1answer
184 views

Replace “Compress” in Finder context menu with other compression app

I've lost some sensitive data because the built-in compression utility generates corrupt files and doesn't show any error. After I compressed about 1 Gb of files with Finder's "Compress", I decided ...
2
votes
1answer
703 views

Can I compress SMS content to free up storage?

My SMS on my iPhone is growing everyday. According to my iPhone's Usage function, I have about 1.2GB of SMS data. My phone has been running on low storage and any megabytes are precious. Is there ...
2
votes
2answers
4k 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, ...
2
votes
0answers
157 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 ...
2
votes
0answers
94 views

Exponential PDF File Size in Preview

I have word document (.docx on a mac) at 3.4 MB. When I save it to PDF it becomes a whomping 90 MB. I can't make it smaller and I can't figure out why it's happening. Here are the details: I've tried ...
1
vote
1answer
804 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)
1
vote
1answer
1k 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 ...
1
vote
2answers
925 views

OSX: move to archive (compress a folder and remove it)

I'm looking for a way to zip (or 7z) files via a file manager in such a way that the original folder is deleted right after the zipping finished (less clutter when batching compression of multiple ...
1
vote
1answer
38 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....
1
vote
2answers
456 views

Is there a Mac utility to create an executable Zip/archive?

Is there a corresponding utility similar to the Windows Zip-to-Exe utility? I would like to compress an archive with a flash presentation (containing a lot of files), and make it executable in Mac, ...
1
vote
1answer
167 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 ...
1
vote
2answers
116 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 ...
1
vote
1answer
45 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 ...