Questions tagged [compression]

Compression decreases the size of data.

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Why does preset “veryfast” in FFmpeg generate the most compressed file compared to all other presets?

The FFmpeg wiki says that the best compression rate is by preset "veryslow". But when I am trying it with my video then preset veryfast provides the best compression in my case. The following is the ...
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0answers
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How to determine which files from C:\Windows\Installer\$PatchCache$\Managed can be removed?

Got an old 2008 R2 server where the C:\Windows\Installer\$PatchCache$\Managed is taking up 5 GB of the 92Gb available. I have been checking all the old threads but not really coming across a clear ...
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1answer
40 views

Very different compression rate with two similar files

I'm using WinRar to compress two text files, of approximately the same dimensions (80Mb), which contain a Json structured text. The text is generated by the same program and, inspecting it, it seems ...
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0answers
53 views

After 7z unzip only the temp word doc is visible (which is corrupt), the original is missing

I have once sent myself a 7zip file when changing computers, when I tried to unzip it, only one of the word documents have seemed to be 'corrupt'. When I later investigated, I have realized that when ...
0
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1answer
28 views

NAS Compression/Decompression

I'm interested in building a NAS to act as a file server for a small number of people (myself being the sole user the majority of the time). I'm thinking the server would run on linux and serve files ...
0
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1answer
33 views

Linux - compress specific files while preserving path and folder structure

So, basically I'd like to do this: Compress only specific files from a folder while preserving folder structure but instead of Windows and 7Z, do it on a Linux and with native Linux tools (no root ...
2
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1answer
74 views

unzip many files with different passwords and compression formats with bash script

I have this bash script to unzip files with different passwords. But it decompresses indefinitely and damages the decompressed files PASS="passfoo passbar passfoobar" LIST=$(ls -1 *.{zip,7z,7z.001,...
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0answers
44 views

When compressing a large amount of files, 7zip stops while only returning “Killed”

Recently a computer of mine died and I'm trying to recover the files (650GB approximately) using a live ubuntu usb to compress the files and then move them to an external HDD. I don't just want to ...
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1answer
74 views

How to set low priority while compressing with wzzip.exe

I have this in batch and the code works without start /low. While compressing with wzzip the CPU is 100% and all other programs hang. So to fix this issue I've been trying to either set affinity or ...
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2answers
63 views

Best compression method for 200gb fixed .vhd

I have a clone of my laptop's hdd saved in the ".vhd" format, as I am going to install the Windows 20H1 Insider release from .iso soon. I have saved it in the fixed format at 200gb exactly through ...
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1answer
53 views

What file format to use for photos? I will edit them. Then I will add text and make a PDF

I want to shoot a few photos using the smartphone. I will receive JPEG files. Next step I will move this photos to desktop computer (Windows 10 Home 64-bit). Now I want to edit this photos: some of ...
0
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1answer
54 views

FFMPEG, resize, watermark and compress a video

I can't quite combine a couple of commands in FFMPEG. I'm trying to Burn in an external subtitle file map all other streams since the file contains many audio and subtitle tracks i don't wish to ...
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1answer
55 views

Why does write speed constantly slow down in 7zip during compression?

Related Question: Why does 7-Zip's compression speed lower over time? So I am compressing files (particulatarly large files, ≥1GB). So I notice that the write speed is slowing down and the ...
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0answers
9 views

Recursively zip files, exclude the folders, but use the folder names for zip naming

I'm looking for a method to script 7zip to zip a bunch of folders in a parent dir, however I want the zips to exclude the folders, and only zip the folder contents. I do however want to use the folder ...
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2answers
87 views

How can you decompress a videofile in ffmpeg?

Example 1: ffmpeg -i input.avi -c:v libxvid output.mp4 The code that I get as output is: ffmpeg -i input_1.avi -c:v libxvid output_1.mp4 ffmpeg version git-2020-02-16-8578433 Copyright (c) 2000-2020 ...
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0answers
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How to find the size of the compressed image?

So, if I have an image in BMP file format being 1024 x 768 and 8 bits (bit depth), I can get the size of the image: 1024 x 768 x 8 = 6,291,456; 6,291,456 / 8 x 1024 = 768 Kb, which is correct when I ...
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1answer
38 views

How to conditionally strip/compress binaries with alternate utilities (i. e. other than strip)

In our yocto-based embedded application, we now have several Golang binaries, which can become very large. For example, docker (from meta-virtualization) and related binaries weigh in with several 100 ...
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0answers
41 views

Reducing size of pdf generated from large docx file?

I have a manuscript for my book that is approximately 600Mb that my publisher requires be in a PDF with a minimum resolution of 300dpi with all fonts embedded and a maximum file size of 1.5Gb. When ...
0
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1answer
46 views

What's happening when I create a file in a “NTFS compressed” directory?

What's exactly happening? The files appear in the UI as compressed. Is it? If so, is it written twice (like, uncompressed version of the new files is stored, as a buffer, and compressed then (so ...
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1answer
27 views

Extract multipart rar with password, deleting parts as they are extracted

how can I use this on rar with password? I know the password is https://superuser.com/a/1031807/1136215
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0answers
30 views

Create “Add to filename.rar” shortcut on Windows10 using AHK

I have a really simple problem which I haven't been able to find the right simple answer to. I'm working with a lot of folders. I want to improve my work speed. After selecting a folder that I need ...
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0answers
39 views

Binary copy of Windows compressed/compacted files to a different location

Windows 10 now have these new algorithms for compact files, which is indeed improved in many ways comparing to the old NTFS build-in compression options. However they are not as 'transparent' as the ...
0
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1answer
64 views

Is it possible to compress alpha and RGB channels of PNG sequence separately with FFmpeg?

Suppose I have a sequence of 32-bit (RGBa) PNG files. Is it possible to compress the RGB channel with one codec and the alpha channel with another? For example, if I had the RGB and alpha as separate ...
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0answers
43 views

“Smart” fast compression for archiving mixed content?

I would like to backup a computer folder quickly to an archive format (e.g. tar, zip, 7z, gz, etc.). The folder contains many files: Some are text files that can achieve a good compression ratio. ...
0
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1answer
86 views

How to make Dovecot maildir format emails be gziped using zlib

I activate compression plugin by set following on Dovecot: # /etc/dovecot/conf.d/20-imap.conf (...) protocol imap { mail_plugins = $mail_plugins zlib } # /etc/dovecot/conf.d/90-plugin.conf (...) ...
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0answers
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File compressor with recovery [closed]

I want to compress a lot of files with a file compressor. I've found that 7z is really good at this stuff, but the problem is that it doesn't add CRC recovery to the file to prevent corrumption in the ...
1
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1answer
358 views

Compressing Grayscale 8-bit PNG Sequences with ffmpeg

I typically deal with many high-resolution PNG sequences, many of which are RGB (24-bit) or entirely grayscale (8-bit). Because adjacent frames in the sequences are very similar, it is important that ...
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0answers
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How create Makeself self executable archive file in LINUX? What is the steps to create Makeself self executable file in any Operating System? [duplicate]

I want to create a self-executable archive using Makeself. I referred to makeself.io but didn't understand anything from it. What are the steps for making a Makeself self-executable archive? If I run ...
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0answers
11 views

Update WinRar archive splited by parts

I have many big csv files with data that I'm collecting in realtime. I want to add new files to archive monthly. What I did before - adding new csv file to big archive and do repack (and after upload ...
0
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1answer
94 views

How to extract original images from a lossless compressed video which is composed from a sequence of images?

I am trying to compress a sequence of images using h.264 with ffmpeg. ffmpeg -f image2 -r 5 -i ori/binary%03d.jpg -vcodec libx264 -preset veryslow a.mp4 ffmpeg -i a.mp4 -q 2 rec/output_%03d.jpg but ...
0
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1answer
33 views

Does 7z compression affected by CPU efficiency

I'm currently archiving a huge amount of data to 7zip, but i've a question regarding the result: Given two processors: 1 very powerfull and the second low-cost -or- Given the same processor but 1 ...
0
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1answer
309 views

ffmpeg video compression: Desaturating colors / losing color information

I'm trying to compress some 4K videos (resolution: 3840x2160) that I've recorded with my Nexus 5X (running LineageOS). My first attempt: ./ffmpeg -i VID_20190908_145514.mp4 -c:a copy -crf 23 -vf "...
2
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1answer
111 views

Do video containers affect video quality ? Or is it just the codec?

Do video or audio file containers (extensions) have any repercussion with the video in itself ? Or is the codec used the only thing that has a repercussion ? For example I have the exact same video ...
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0answers
53 views

How do I access this hashed/compressed/encrypted backup data when I'm the owner?

I recently did a backup of my xperia phone onto my computer using the Xperia Companion Application. I checked to backup apps and media in the procedure. After everything finished, I looked at the ...
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0answers
77 views

OPNsense, OpenVPN to Yeastar PBX: Error - Bad LZO decompression header byte: 42

I'm pretty new to OPNsense and VPN's. I have OPNsense set up on a virtual machine and I'm using it to access multiple Yeastar PBX's. I access some the PBX's fine but the there are some that I'm having ...
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1answer
39 views

Windows compresses folder without asking where to put it

When I right-click on a folder I want to compress, then right-click > Send To > Compressed (zipped) Folder, it just starts compressing. It doesn't go through the normal process of asking me what the ...
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0answers
284 views

How do I compress many files into independently working WinRAR files?

I want to upload a vast amount of small files to a website. To make that process faster, I compressed them to a .rar file. The problem: Such a large file can't be uploaded to that website. That's why ...
2
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0answers
55 views

Compressing many similar small binary files independently using a preset dictionary

I have to compress many similar small binary packets (about 1.5 KB a packet) for data transmission. I tested .xz format on a 306 MB sample and I got 50% compression ratio (compressed to 153 MB). But ...
0
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1answer
124 views

Compress multiple folders with Winrar command line and batch

I want to compress all the folders that contain the word (Album), these folders have the following structure Michael Jackson\Invincible (Album) Michael Jackson\Thriller (Album) Luciano Pavarotti\'O ...
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0answers
115 views

Is 15 million page faults usuall for the process Memory Compression?

I have a windows 10 PC with 8GB of ram, an AMD Ryzen 5 (3.2Ghz) and a GTX 1050 Ti. It will run very smooth when I am not doing things but struggles whenever I try and do a lot of multitasking, despite ...
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3answers
70 views

Is there a disk image file format that only store sectors which are filled (non empty)?

I have a 500GB hard drive that contains several NTFS partitions. I would like to create a single disk image of all partitions. My ultimate goal is to mount that drive later and scan it for possible ...
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0answers
52 views

How can I get the Compy Data Compression proxy to work?

I tried to set up a Compy with HTTPS and MitM support, and I connected my iPhone to it but I keep getting these two errors whenever I try to load a page. I don't understand what I did wrong but i'm ...
0
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1answer
38 views

constantly trying to compress filesystem

is there a filesystem that constantly looks for ways to compress data using a small amount of processing power? particularly i'm looking for a way to dedupe files within various archives (.bz2, 7z, ....
33
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1answer
4k views

7-Zip seems unable to compress zero-filled virtual disk image after 1.8 GB

I am trying to compress a virtual disk image that is mostly empty. It has about 2 GB used out of 13.5, but even after zero filling the empty space, I am still only able to compress it to around ...
0
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1answer
37 views

How to get 7z parameters values

I've found that the (undocumented) 7z -mx4 option gives the best time/compression ratio for my files: 7z a -r -mx4 outfile.7z infile.dat Now I'd like to fine tune the parameters to get even better ...
0
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0answers
41 views

Is it possible to open a file with Windows compressed-folders ability without it having a .zip extension?

In Windows (10), is it possible to open a file without a .zip extension using Windows native compressed-folder ability? I occasionally have apps I need to append a .zip extension onto in order to ...
0
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1answer
56 views

How to achieve better compression ratio in 7z format with HEVC files

I use an open source compression software named Peazip running on a Intel Core i5-8250U @1.6 GHz processor. However, I have tried compressing files to 7z many times but the compression ratio is hardly ...
0
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3answers
70 views

Is there a way to estimate how much space a file or directory of a given size will take up after being compressed with tar and bzip2?

Due to an imminent distro switch, I would like to backup my home directory. However, my home directory is 29 gigabytes. I would like to know how much space this would take up after being compressed ...
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1answer
41 views

What software is used here to compress jpeg?

https://compressjpeg.com/ The copression level is pretty inpressive, and I would like to use that encoder (or something similar) offline.
2
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1answer
489 views

Unusual behaviour with a passworded rar being invalid password in winrar but falsely accepted in 7zip

I found an old .rar file on my computer but I couldn't remember the password exactly. I had a rough idea of what it was, so I wrote a program using 7ziplib in c# to brute force a bunch of permutations....

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