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Questions tagged [compression]

Compression decreases the size of data.

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7zip - Password error in destination server

I created a 7zip archive encrypted with AES256 standard, and moved it to another server using a external hard disk. Before moving, I took the checksum using fciv. The archive is around 120 GB. In the ...
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19 views

What needs to be changed in this archiving script to only archive specific file types?

I made this script based on past answers from superuser, but now need to only archive specific file types. I messed around trying to use wildcards but nothing I tried seemed to stick. If I wanted to ...
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46 views

Is solid RAR5 archive safe enough for NAS storage? [on hold]

I've recently bought a NAS to store games and software I've collected through the years and my intention is to put them in compressed archives.I have two very simple questions: Should I worry about ...
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21 views

How to update a zip file in ssh? (Ubuntu)

I use zip to backup a website public folder (4 GB zip) daily. Is there a command to update the same zip file without creating from scratch each time? It should do 3 things: If file exist on zip, ...
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23 views

Are USB Mass Storage data compressed when transferred?

I have found I have unused partition (~1 GB) full of zero bytes. I ran xxd -a on it and it looks transfer is somehow compressed. xxd outputted the first 8 bytes and then it was reading data until ...
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14 views

Periodically update compressed file to reflect directory?

I have a large folder, 10GB+ in size, that I would like to compress into a ZIP file other compressed single-file format. The contents of this folder changes, and I would like the compressed file to ...
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1answer
17 views

Tiff or JPG in PDF?

I have a bunch of scanned PDF (e.g. picturebased pdfs). When I run them through "pdf optimizers" online they frequently are reduced 70-80 % in size with hardly any noticeable difference in quality. I ...
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18 views

Compress still image ffmpeg

I tried to find by myself, but understood what this none easy what I'm thinking. Please help me find optimal way. I need compress this video with 1080p demension, but more less wight. It contain ...
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1answer
97 views

CPU barely utilized when compressing with 7-zip

When I try to compress with 7z maximum compression, my CPU utilization is under 20%. Only one of the cores is 100% loaded, and not even 100% of the time. I'm on a fast SSD, so it's definitely not ...
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2answers
27 views

How to best compress MP3/Flac so that download time is less?

How to best compress MP3/Flac so that download time/data is less? (like RAR and else) I'm afraid I get restricted access from my ISP.. so I want to compress the files as much as possible... if the ...
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1answer
39 views

7zip force ignore NTFS junctions

Windows 1803, 7z 18.05 Trying to archive and compress a folder structure with multiple NTFS junctions referencing parts of the said structure (i.e. no "outside" links) - any possibility to compress ...
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18 views

Screen recording has audio “stripped” when compressed or shared

Short question : I have taken a video screen recording on my iPhone and imported it to my computer, when i try to compress or share the file it keeps stripping the audio from the video and im just ...
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30 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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94 views

Convert (compress) JPEG images using mogrify keeping the original files in the same directory

I'm trying to convert(compress) a bunch of JPEG images using imagemagick command mogrify, keeping the original file in the same directory. I'm typing in terminal window : mogrify -quality 25% *.JPEG ...
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1answer
77 views

libx265 & ffmpeg: the better compression, the larger files?

Trying to squeeze the last bit, I made the finding, that my files get larger then smaller. Unfortunately I must have misinterpreted some parameters. Maybe you can help me. The reference is -preset ...
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20 views

Quickest way to store (uncompressed) in a .zip file [closed]

I want all my music files to be in one location for easy syncing with my portable media player & for creating backups. However there are a few albums/tracks I don't wish to sync. I don't want to ...
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2answers
141 views

How do I see and set the NTFS compression attribute in Linux?

Browsing an NTFS partition in Konqueror or Dolphin, the compressed files and folders are not displayed with blue names, and there doesn't seem to be any page in the file properties dialog to see or ...
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3answers
66 views

Is there a USB file copy protocol that makes zip file copy faster?

I apologise that I cannot provide any source other than mentioning a quote from my friend. (This is almost a question for skeptics.stackexchange) He said there is a protocol because of which copying a ...
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0answers
32 views

LTO-6 with Hardware Encryption Enabled using LTFS File System Possible on HP Ultrium?

I've googled this issue, but can't seem to find an answer to point me in the right direction - or if this simply is not possible. My HP Ultrium LTO-6 Drive supports AES-256 Hardware Encryption as ...
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1answer
40 views

Can Files Be Compressed Without Changing Extension?

It's common for web servers to pre-compress their files with brotli or gzip. And they do so without changing the extensions of the files. Is their a way to do this in a typical desktop environment (ex....
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40 views

How to create flag which will indicate completion zip / compress operation?

I am using 7-zip and I would like to run zip operation on dir/files. My requirement is to get certain flag say some file (complete.flag) in a directory along with zipped content to indicate zipping ...
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1answer
77 views

Largest possible compression for big video files using FFmpeg

I've been fascinated by a copy of “The Emoji Movie” being compressed to 45 megabytes, and was wondering how would I go about achieving such compression to very large movies. Of course, if some ...
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1answer
46 views

Detect if a Windows filesystem supports built-in file compression?

Windows NTFS supports built-in folder and file level compression. Windows FAT does not. (And there are others which fall into one of those two categories as well.) How can you detect whether or not ...
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1answer
27 views

Is it possible to check if a 7zip archive contains the same contents as a directory?

I have a folder on my external hard drive for saving minor backups (G:\LOG), whose contents I have compressed as G:\LOG\LOG.7z. However, I am unsure as to if this was entirely succesful. The folder is ...
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1answer
31 views

Is there a way to check how much a file can be compressed without actually compressing it?

I have a large (80GB) virtual drive file which I want to compress but, before I do, I want to see how compressible it actually is, before embarking on creating another (potentially) big file (if it ...
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1answer
70 views

Why does 7-Zip deflate 257 and 258 word sizes?

Compression word sizes are usually powers of 2. Yet, 7-Zip has some exceptions: Deflate has both 256 and 258 word sizes. Deflate64 has both 256 and 257 word sizes. These seem like such trivial and ...
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1answer
41 views

Why does gzip -c give different results than gzip?

I am writing unit tests for some code and found that a simple gzip is causing a difference in my results. Upon further investigation I found that gzip gives a different .gz file than gzip -c does. Why ...
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1answer
32 views

Compressing a large number of files

I know that compressing files reduces the size of the files, sometimes at the expense of quality, so I was wondering how to compress a selection of files whose total size is larger than the maximum ...
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1answer
111 views

7zip on several terabytes, drive already compressed [duplicate]

so, I have a drive that is NTFS. it has thousands of graphics/video files that totals to about 6TB. I wanted to compress and send this info to someone. What is my best option for compressing? I've ...
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1answer
246 views

How to add password command in zip bat file

I have a script below which is working perfectly, all I need is to add a password & encryption while compressing. Any idea where do I put the -p command to make it work? I tried but it is not ...
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1answer
45 views

FFMPEG: H265, -Preset Options Are Out Of Order

With H264, the higher the preset (ex., -preset 9), the slower yet better the compression (the wait is long long but the file size is small). However, with H265, I found that -preset 2 gets the best ...
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1answer
152 views

Log rotation with compression?

I'm running a process on Linux (CentOS 7) which produces a lot of output on stdout. Sending it all to a file will result in a file size greater than 1 TB. But happily the output is quite compressible -...
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2answers
50 views

Is it wise to use compressed NTFS Windows Vmware stored on a compressed NTFS drive?

I have a Windows 10 vmware box stored on a compressed NTFS drive. So, my question is whether it's a good idea to use compressed NTFS on the "C:" drive of the Windows 10 vmware box (i.e. compressed ...
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1answer
50 views

How to compress a bunch of files efficiently?

Let's say you have a lot of files to archive. They are in several different file formats (txt, docx, pdf, png, jpg, mp3, zip, etc.). What are the best practices to compress them all, so that they ...
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0answers
54 views

Control the order of extraction in 7zip

Suppose I have three files, file2.txt, file1.txt, file3.txt I want to 7zip these files in the same order and extract them in the same way. I'm aware that these files when compressed will ...
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0answers
31 views

How to view specific path inside tar.gz?

tar -tf file.tar.gz let's me view inside the whole archive. How do you view a specific path without viewing the whole thing? E.g., I want to view only /path/foo/ Update: This command almost works ...
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343 views

The built-in Windows folder compression reduces free disk space instead of increasing it

A few months ago I did not have enough free space on my Windows 7 drive so I went ahead and compressed some big folders with the built in compression tool in Windows which is accessed from the ...
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2answers
350 views

Compress all images in Excel workbook

I have a workbook with over 150 worksheets. Each sheet contains an image that was copied to each work sheet from another 150 sheet workbook. The process was done by manually copying image 1 from ...
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2answers
59 views

Batch file for 7zipping all folders into .7z directories (no subfolder left inside!)

I'm sorry this has probably been asked numerous times before but I'm tearing my hair out trying to fix my batch code and I can't find a specific answer which I can use to correct my own code. I have a ...
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2answers
1k views

Win 10 Home v 1803 - Remove blue arrows on compressed file/folder icons?

Anyone know how to remove the blue arrows displayed on compressed file/folder icons in Win 10 v 1803? Apparently there was a simple registry tweak to remove them in older versions of Windows 10, but ...
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1answer
40 views

Hi , I have some problems in compressing anything,it not become smaller file size. I am using window 10,7 zip ,compression level-Ultra,

I have some problems in compressing anything,it not become smaller file size. I am using window 10,7 zip ,compression level-Ultra,etc..shown in web. But it compressed only little smaller size .eg I ...
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0answers
51 views

Extracting (or copying) files to a compressed NTFS folder makes Windows report the disk is full when it's not

I've been trying to extract a series of compressed files - total ~50GiB (uncompressed) - to a hard disk with about 55GiB of free space. Because this is a slow hard drive and with limited capacity, ...
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1answer
690 views

What archive compression makes .mp4 files the smallest?

Is there an archive-based compression format that is known to make the smallest .mp4 videos? I did a test 1080p 0:12 duration video with the only archival formats I know about: (python3) Joshs-MBP:...
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0answers
62 views

Getting E_NOTIMPL error when using -v option with 7zip on Debian

Running Debian 9, installed 7-zip 16.02 (64-bit) from debian repo. I'm attempting to create a split 7zip archive, and I receive this error message: 7z a dir1.zip dir1 -v1k 7-Zip [64] 16.02 : ...
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1answer
53 views

Is there a limit to zip-on-zip compression?

I recently made a 10.5GB file of all zeroes, and started zipping and duplicating it, similar to a zip bomb. The compression per-layer was: 1st layer (the 10.5GB file): very high compression (about ...
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0answers
48 views

Exiftool's “-tagsfromfile” does not help recover all metadata (#iphone)

This is a long standing practical problem (more than one year). I always want to finish it, but every time I tried I failed. I have consulted several threads for it. I have a bunch of daily-life ...
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2answers
28 views

If I lose a DVD that contains a zip file part, will I need to make the whole collection again?

I have been backing up my data to some DVD-DLs, and I still have the original data. But when I burned it to disc, I compressed it in a zip file to make parts of it. Now one of the disc accidentally ...
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1answer
104 views

How to uncompress file

I am trying to uncompress a unknown file type. I used file command file sample.file sample.file: gzip compressed data, was "/groupts/7bi/e7/ciuyuyout/Dump/SplitFastq/327264/ou", last modified: Wed ...
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0answers
49 views

Cannot zip a mutli-part archive, zip -FF command failing with out of memory error

Command zip -FF xxx.zip --out final_xxx.zip Fails with zip error out of memory or zip error : cannot split, read, write, file is too big.may be result of bad comrpression , try -fz I do not how try ...
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1answer
135 views

Zip vs tar (no compression)

I am currently working on changing all the computers for a company. To do the data transfers to the new computer I must either transfer it directly, or through the network by making a huge big file. ...