Questions tagged [compression]

Compression decreases the size of data.

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Pine64 fails to compress videos with ffmpeg and H264

I have a Pine64+ (1GB) - A64-DB-Rev B (2016-02-24) with an All Winner Tech chip. I'd like to use to compress videos from 4K to 960. I installed Armbian using these directions, I verified that ffmpeg ...
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Dictionary Size and Compression Method

I have knowledge about archiving, since I already try it so many times in a basic way just right click and add to archive then press ok, but it is my first time to modify it using the settings. I want ...
Richard's user avatar
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Unable to decompress file with gzip

I have a file called myfile.dat.gz that I need to decompress. I have been trying gzip -d myfile.dat.gz, but this results in the error gzip: myfile.dat.gz: invalid compressed data--format violated. ...
formicaman's user avatar
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In what order should I use stabilization and compression with ffmpeg?

I shoot videos of soccer games on a Canon Vixia which records at 60fps HD with h264 compression. From the camera it results in 20GB files which I have been recompressing (to save on storage and ...
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How can I reduce the file size of a video encoded with wmv2 in ffmpeg?

I have some videos of a slide presentation with audio and need to put them in a wmv container. These videos are intended to be viewed with Windows Media Player. I initially made the mistake to use the ...
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btrfs volume in fstab fails to boot with compress-force

in my fstab, the btrfs volume boots with no problem when the option set is compress=zstd:15, however, as soon as i set it to compress-force=zstd:15, it fails to boot because of a failed dependency ...
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Extract timestamp of I-frames of video using ffmpeg

If I understand correctly, I-frames are the frames that are unaltered during video compression. I want to extract the exact timestamps of these I-frames and save the output in a txt file. How do I do ...
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How do i unzip files with 7z and do not replace files that have the same name but different hash?

How can i tell 7z to extract all the files in the directory, tell it to do not replace files that have the same name but different hash? preferably tell it to extract the files and rename them to ...
OneAndOnly's user avatar
243 votes
3 answers
59k views

Why are tar.xz files 15x smaller when using Python's tar library compared to macOS tar?

Context I'm compressing ~1.3 GB folders each filled with 1440 JSON files and find that there's a 15-fold difference between using the tar command and Python's built-in tarfile library on macOS or ...
Saaru Lindestøkke's user avatar
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how do i use fuse to mount a file in a compressed file as a symlink

i have a directory full of .xz files, each containing a single file (not tar). uncompressed, the directory is 23GiB. (*.xml) compressed, the directory is 1GiB. (*.xml.xz) how do i fool the filesystem ...
loud_flash's user avatar
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Find out which version of which specific program created a (partial) ZIP archive

Is it possible to determine which specific version of which specific program created a given ZIP archive, based on its metadata? And also, is the outcome of a ZIP / RAR compression affected by the ...
GabrielB's user avatar
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recompressing .gz and .bz2 files to attain the same hash/checksum (mod timestamps?)

i want to duplicate the entire contents of wikimedia's dumps, monthly, and upload them to amazon glacier and/or tape backup and/or a third backup medium that can survive corporation collapse/...
loud_flash's user avatar
5 votes
1 answer
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How to recover a bitcoin wallet on a Windows drive amid 30 gigabytes of files

I need to recover a bitcoin wallet that I created about 8 years ago. I was a kid, and I thought I would be super clever and zip or rar the wallet, then change the extension to an image file. I ...
marsh's user avatar
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Compressing pdfs

I've been using a web service at ilovepdf.com to compress some PDF files. And by some, I mean "several hundred to several thousand". The output files look identical (to my eye) and weigh in ...
John O's user avatar
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Uncompress .tar.gz format getting error "tar: Unrecognized archive format"

I've downloaded a ".tr.gz" file with a size of 10 GB from here (after downloading completed, I renamed it and deleted .partb to become dataset cleaned.tar.gz) while I'm trying to uncompress ...
Rawan's user avatar
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RAR command-line: how to include a directory (recursively) but with another name in the archive?

I have read RAR a folder without persisting the full path which helps about the RAR -ep1 switch but I still have the following problem: I want to add the directory D:\Temp\FolderA and its ...
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Which Folder to File method compresses the most? zip vs tar.gz vs tar.bz2 vs tar

I'm trying to download a large Gitlab repo in a script, and Gitlab offers each of the zip, tar.gz, tar.bz2 and tar options, and I want to pick the one that will have the smallest file size. Will one ...
Dr-Bracket's user avatar
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Creating GPG encrypted tar.gz Backup fails

I hope this kind of question is ok here ;) I am on Debian 10 Buster, trying to create an (GPG) encrypted, compressed tar file without intermediary files. I found this article[1] on the web which ...
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Compress all files to the "9" level with gimp

I created the scripts from Using Gimp to batch convert images to another format in Windows tip made by @forrest-voight. Can anyone tell me how I can add options to this script so that the maximum ...
dez's user avatar
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Compress PDF of images without downsampling

How can I compress a 300 DPI PDF of images without downsampling? e.g. without using gs or alternative to convert it into a 150 DPI PDF? I'm looking for something like https://docupub.com/pdfcompress/ ...
Zaz's user avatar
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NTFS Folder Compression Fades

I am on a Windows Server with limited disk capacity. I used windows build in compression of folders to compress a 30 Gbyte file to 22 GByte. I noticed that while running a programm which frequently ...
Tobi T's user avatar
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Best way to clean up over-compressed audio with a clean sample in Audacity?

I have an audio file, which sounds a little muffled due to compression (it's not very bad however). I want to clean it up as much as possible with Audacity or similar (free) software. I have a high ...
mikey_john's user avatar
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FFmpeg HEVC compression?

I'm part way through a video processing program and am using ffmpeg to read a frame, process it and then write it to an output file. Input files are HEVC codec and are currently being read and then ...
Pentacle's user avatar
1 vote
1 answer
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Why do I see strange characters when using “cat” on a zlib compressed file?

When I try to run the cat command on a zlib compressed file, I get this sequence of strange characters xK??OR04d?H????/?I;{<% Where they come from?
user1255022's user avatar
-1 votes
1 answer
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WinRar is acting weirdly

I tried to unarchive a 40 gig zip archive in my d drive which at the time had 120 gigs free but i was greated by a message that i don't have enough disk space i was really confused and i decided to ...
troliadorska polska's user avatar
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2 answers
373 views

How to compress an image as much as possible?

I have an image with a size of 1x1. (.png) It's a black pixel. I used Photoshop to create it as a Bitmap and when I saved it, it turned out 1.2kB+. This was not very surprising, I thought Photoshop ...
mesrefoglu's user avatar
1 vote
1 answer
811 views

Why are ffmpeg processed videos per default multiple times smaller in file size than the input file?

I have a mp4 movie of 1:15min length, made with the Sony Alpha 6400 4k camera. It has a size of 528MB. I want to cut it using ffmpeg. Although I only cut a few seconds, the new video was much smaller. ...
Lion's user avatar
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Ffmpeg decompress xz/gz/zip in memory

I have a xz compressed y4m raw video file (sintel-4k.y4m.xz) and I would like to transcode it using ffmpeg, decompressing in memory. I do not have enough disk space to decompress the file to disc and ...
Rubydesic's user avatar
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How to compress one folder into multiple .zip, all independently extractable?

I work with some big image datasets containing millions of images, and I often need to compress the results of each step of processing to be uploaded as backup. I have seen that some datasets can be ...
LemmeTestThat's user avatar
1 vote
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108 views

OBS settings for recording presentation (still screen) with mouse cursor in low size and good quality?

How could I reproduce these settings with OBS Studio FFmpeg recorder? Format : MPEG-4 Format profile : Base Media / Version 2 Codec ID : mp42 (isom/mp42) Format : AVC Format profile : [email protected] Format ...
Rudolph's user avatar
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How to change password of multiple ZIP archive files at once?

I have 50 password protected ZIP compressed archive files. By design, all the files have the same password. I now want to change the password for all those ZIP files to a different password (again, ...
End Anti-Semitic Hate's user avatar
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Compressing an MTS file to MP4 gives error in QuickTime

I have a long video file that I want to trim, resize, and compress with H264: ffmpeg -y -ss 1.2 -to 2:03.800 -i long.MTS -vcodec libx264 -vf scale=320:-1 -vb 500k short.mp4 The file plays in VLC and ...
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Auto-Transcode/Compress .mkv to .mp4 on Qnap TS-251+

I rip my DVDs with MakeMKV in order to be able to watch them on my TV, as I do not have a DVD-player that supports any output connector that fit into my TV as the TV is relatively new whereas the DVD-...
DarkDiamond's user avatar
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How can I count the number of files inside a tar.gz file (don't want to decompress)

I have a tar.gz file (neatly 1TB size). I want to count the number of files inside this tar.gz file. I used the following command tar -tzf file.tar.gz but it only lists the file name while I need the ...
Taufiq's user avatar
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WIM file compression

I build a custom windows 10 installer via sysprep (windows 10 pro Build 20H2). The windows created WIM-file is too large to my liking, over 9gb (want it to fit on a 8gb drive). Therefor I was trying ...
Mad_piggy's user avatar
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"Windows Sandbox failed to start, virtual hard disk files must be uncompressed and unencrypted"

I have Windows 10 Pro and I successfully installed Windows Sandbox. However, when I try to run it, it shows the following error: My (physical) hard drive is indeed compressed (NTFS compression) and ...
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1 vote
1 answer
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Piping Unrar Output to FFMPEG

I have a password protected .rar file. It's large, so using unrar e large.rar is time consuming. Once extracted, the file will be large.avi Then I have to do ffmpeg -i large.avi large.mp4 I was hoping ...
Christopher Sparks's user avatar
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51 views

Extract zip files and recompress them into 7zip files [duplicate]

I'd like my zip files to be extracted, then recompressed into 7zip files. Example: Before: $ ls 001.zip 002.zip 003.zip --snip-- 997.zip 998.zip 999.zip After: $ ls 001.7z 002.7z 003.7z --snip-- 997....
twlscnds's user avatar
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How would I make an executable that contains compressed files, and runs one on execution of the file?

Ok, so imagine you have a self-extracting compressed file with the following contents: x.exe images/y.png sfx/z.wav When a user clicks on the compressed file, it runs x.exe instead of extracting ...
Seth's user avatar
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5 votes
2 answers
7k views

How to convert .tar.gz to .tar.xz?

How to convert .tar.gz to .tar.xz? I have a bunch of .tar.gz files that I would like to convert to .tar.xz for a better compression. How to do this efficiently? A command like this would be great: How ...
Philippe Remy's user avatar
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0 answers
1k views

How do I mount LZMA filesystem or extract to modify them

I am working on a firmware with binwalk a bunch of LZMA compressed data ... -----------------------------------------------------------------------------------------------------------------------------...
Anindya Roy's user avatar
2 votes
1 answer
208 views

Lossless or near lossless compression options for PDFs containing grayscale with JPEG2000?

I have some older books (pre 1900) that I'm working on archiving to a digital format. Most of the time using greyscale is satisfactory in terms of color preservation, however I'm having trouble with ...
ylluminate's user avatar
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1 vote
1 answer
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Rar is not recognized as an internal or external command

I installed winrar in D:\folderD, both at home, and at work. I have a .rar file in drive E:, E:\folderE\myfile.rar. So, at home I can successfully use the Windows Command Prompt in drive H: with the ...
ldnamdd's user avatar
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2 votes
1 answer
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7zip: how to convert Linux SFX archives to Windows SFX?

I need to compress some files in archives that can be opened by everyone using a Windows PC without 7zip installed. I thought of running 7z a -t7z -m0=lzma2 -mx=9 -mfb=64 -md=64m -ms=on -sfx -pXXXXXX &...
Polizi8's user avatar
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Compress PDF file to a selected size

I have a 60mb PDF file I need to reduce it to 10 mb. I was wondering if there are any tool to do it.
Roby Sottini's user avatar
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2 answers
2k views

less command does not open zip files on debian

Here I am using debian/testing distribution on my machine but there is something interesting. # less file.zip "./file.zip" may be a binary file. See it anyway? Do I need to install some ...
M.J's user avatar
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1 answer
881 views

decompressing multiple bz2 files into 1 csv file

I have 16 bz2 files of bz2 format: split.csv.0.bz2 split.csv.1.bz2 split.csv.2.bz2 .... I believe this is a compressed csv file, but what makes me confused all day today is that it's splitted by 16 ...
Daniel Kim's user avatar
-1 votes
1 answer
1k views

ffmpeg - losslessly compress upscaled video

I cannot seem to find a good answer to this. I have a video file, h264, 1280x720, 251.2 MB. However the video is upscaled, the actual quality is 1024x576. And not just the numbers are different, there ...
mikey_john's user avatar
0 votes
1 answer
204 views

Compressing video consisting mainly of text and still images (Powerpoint slides)

(NB This question is largely a duplicate of Best video codec for filmed powerpoint presentation but that question is 7 years old and I hope to see if there is new advice. I don't have enough ...
Dave Winterborne's user avatar
3 votes
1 answer
636 views

Disable NTFS Compression, but only for new files

I have an external NTFS drive which I enabled compression on a few days ago. I thought it would help save disk space, but only saved about 1% overall. Now disk writes seem much slower and the ...
GDP2's user avatar
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