Questions tagged [compression]
The re-encoding of a file or data into a form that uses fewer bits of information than the original data.
92 questions
0 votes
1 answer
82 views
Why/How does Image Capture make TIFF scans 85% smaller when rotation is applied?
When I use Image Capture to scan a 4x6 print photo on my flatbed scanner at 600 dpi, with no rotation applied to the bounding box, the resulting TIFF file is generally around 11 MB in size, and the ...
- 392
0 votes
0 answers
521 views
Why can’t Mac compress files faster than ~60MB/sec or so?
It seems like this has remained relatively constant over the last 5+ years or at least as long as I have been paying attention. Files on an internal SSD can be copied to other drives much faster… ...
1 vote
1 answer
100 views
Could a 163-bytes size difference between the tgz of two different 590mb dirs be caused just from file metadata? Or is the file data diff?
While trying to remove duplicates of MRI readings I am tarring / compressing (tgz) the top-level directory with a mix of executables, pdf, text, dll, and data in proprietary format (but sometimes with ...
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0 votes
0 answers
148 views
How do I compress an encrypted time machine disk image?
I have an archived read-only Time Machine drive sitting on a NAS. It is a straight dump (made with dd) of a CoreStorage encrypted HFS+ hard disk. It's taking up 10TB, and I expect that the much of the ...
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1 vote
0 answers
892 views
Unable to compress / zip zero byte files in external exFat drive in Mac OS
Why can't I compress/zip a zero byte file which is located in an external exFat drive in Mac OS ? I keep getting this error, The operation couldn’t be completed. Undefined error: 0. I have some marker ...
- 170
0 votes
4 answers
796 views
Is an image as ".jpe" an ordinary JPEG, just with a different file extension?
I have a little dozen images with the file extension *.jpe. All the others are the well-known *.jpg, *.jpeg and so on. Can these images be renamed from *.jpe to *.jpg? Is there any difference to *.jpg?...
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2 votes
1 answer
2k views
Best compression format for backing up many MacOS files (7Z, GZIP, BZIP2, etc)? [closed]
I want to take a backup of the folder ~/Library/Application Support/MobileSync which houses my iOS Backups on my MacOS computer. To do the backup, I'm planning on archiving this folder with file ...
- 10.4k
1 vote
0 answers
240 views
What compressed file formats does the Files.app support?
What compressed file formats does the Files.app support extracting from? I can't seem to find any official documentation to this effect. Any trial-and-error tales?
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1 vote
0 answers
867 views
Compress $HOME Directory Using tar.bz2 | macOS 10.15.7
Not interested in using Time Machine in this case. Trying to backup the $HOME directory and am producing an error at the same location no matter the command so far: ~/Library/Containers/com.apple....
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3 votes
1 answer
775 views
How do I compress a file into .xip format?
I wanted to compress the Xcode.app I downloaded from the app store into .xip format. Is it the same as compressing it to .zip and renaming?
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0 votes
1 answer
191 views
Difference in archive formats?
After a little testing, I can't figure out what the difference is in the archive formats listed in the Preferences > Use archive format. Each time I compress a folder, each one has the same ...
- 2,417
1 vote
1 answer
632 views
Compress file as .tar.gz instead of .zip
If I right click a file and I compress it I obtain a file.zip. Is it possible to set right click-->compress to produce a file.tar.gz as output? I always have to do it through terminal but many times I'...
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1 vote
1 answer
1k 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 .svgz ...
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4 votes
1 answer
644 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 ...
- 139
5 votes
0 answers
462 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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