Compression decreases the size of data.

learn more… | top users | synonyms (1)

1
vote
0answers
507 views

Increased data usage on a VPN connection

I have been working on a remote computer over a VPN connection using Windows 7 Remote Desktop Connection. I RDP from my laptop (with non-HD display). Recently my wife has also been working from home ...
0
votes
1answer
55 views

Strange behavior encountered while using tar

I had a folder of useless C programs for a project. When I was compressing it using tar, I kept using tar -cvf c-project and then realized I'm setting the flag for the file name and I'm giving ...
2
votes
1answer
753 views

How do I find out the compressed / uncompressed file sizes on btrfs?

I am using btrfs on one of my hard drives. I would like to know the actual file size and the compressed file size on btrfs. I am interested in seeing the compression ratios per file . For example ntfs ...
2
votes
1answer
49 views

How do I reinforce compression options?

Shortly after I got my computer, I enabled NTFS compression on it, selecting the option to compress "all files and subfolders". I recently noticed that several folders on my PC are not compressed ...
0
votes
1answer
107 views

Extracting one file from archive: 7-zip requires decompressing entire archive?

I've noticed that when browsing an archive containing multiple files with 7-zip 9.20 Windows GUI, extracting one file for previewing takes significantly longer with .7z than .rar archives. With .7zips ...
2
votes
1answer
1k views

What does the number after 7-zip's -m switch mean?

7-zip has a command line switch to set the compression method, -m followed by a number, e.g. -m0=LZMA. What does the number (0 in the example) mean? Different numbers produce slightly different ...
1
vote
0answers
132 views

How to make compact.exe to compress only folders, but not files?

I have a large and complex nested folder structure on disk. Say, Folder1 <many files> Subfolder1 <many files> Subfolder2 <many files> ... SubfolderNNN Compressing all ...
2
votes
1answer
255 views

tar: compress only the contents of a folder

I have to compress only the contents of the folder, not the folder with tar, there is any argument for that? I have search but I don't find anything. Example: mainfolder/ asd1 asd2 ...
0
votes
1answer
472 views

zip sub folders individually

can anyone help me make a batch file for my problem. i have multiple folders that i want to compress individually. root folder 1 file 1 file 2 ...
0
votes
1answer
71 views

Human insensitive video compression

I have an AVI video file recorded by my laptop web-cam. It's only 10 minutes but it has so large size, 3.9 GB! I'm not expert in multimedia but I've seen really good quality long movies in only 4 GB. ...
4
votes
1answer
3k views

tar/bz2 compress a file removing uncompressed original

Is there any way to turn a directory called dir1 into dir1.tar.bz2 without keeping the original? I need to save space and want to compress some large files but don't have enough room to keep a ...
2
votes
4answers
213 views

What other archive formats save Date Created and Date Accessed?

7-Zip on Windows will save the Date Created and Date Accessed when compressing a .zip file, however it does not do this for its (referring to 7-Zip) native .7z format. Any Unix-based formats are ...
1
vote
2answers
5k views

What is more efficient / faster, rsync compression or ssh compression?

I currently rsync files: (i) locally and (ii) remotely over WAN (connection c. 8mbps down / 1.5mbps up). I am considering adding to rsync: -z to compress files. Or alternatively adding to ...
2
votes
1answer
1k views

Windows “Send to Compressed (zipped) Folder [in different location]"

Is it possible to change the “Send to Compressed (zipped) Folder" functionality to create the zip file in a pre set directory, rather than the current one? Also, any information anyone can share ...
1
vote
2answers
191 views

How much can data be compressed? [closed]

Is there a scientific limit to how much data can be compressed? What I mean is, compression is essentially representing a larger amount of data with a smaller one, such as representing a=abc b=def ...
1
vote
2answers
3k views

7-zip command line -p switch not working according to help page

I want to be able to automate the encryption of the file type .pcapng in a windows batch script. My current problem is that I get an error when extracting the encrypted file saying something along the ...
0
votes
1answer
87 views

How can I zip or rar file names in txt file from command line?

I'm using a batch script to output filenames with specific attributes to a .txt file, in this case older than 30 days. I'd like to then zip or rar those files that are listed in the .txt file. How ...
2
votes
1answer
238 views

Compress the silence - audio file formats

How do you compress audio silence? I'm using Audacity and have been exporting variable compression mp3s. But a 1minute audio track is about the same file size regardless of how much silence there ...
0
votes
1answer
226 views

How to keep daily tar.gz backup with less redundant data

Like most of you, I have a few daily tag.gz snapshot of a folder (of any application). There is only a few different each other but the tar.gz is not a diff/delta friendly format. Most data in the ...
3
votes
4answers
2k views

Should I compress hard drives containing large video files?

I have a media computer that stores large video/movie files of about 8GB per file... It is also used for media playback. Is it a good idea to compress the hard drives? how much space would I gain with ...
0
votes
2answers
416 views

Is there a ZPAQ implementaion that integrates with GUI compressors like File-Roller?

I've tried a number of ZPAQ implementations for Linux, but I don't like that they are all command-line programs, and thus require a lot of typing to get simple things done. My file browser supports ...
0
votes
3answers
251 views

What are good compression algorithms for delta synchronization?

When syncing large files over a slow link, it is often useful to use delta compression in order to reduce the bandwidth used. It is also useful to compress files as they take up much less space. ...
1
vote
1answer
359 views

Lossless screen video capturing

Can you capture/record a video playing on the screen using a recording software(or your custom code) such that every pixel is recorded and there is no loss of information ?
1
vote
2answers
265 views

Advanced backuping script

I'm currently writing an advanced starting script for my minecraft server. Everything works out as I want it too. But the problem is the backups. I created a function for it. It works also great and ...
0
votes
0answers
172 views

How can I get RAR to create a segmented archive (volumes) when compressing from stdin?

I have this ZFS box where I'm creating incremental snapshots, then piping them into RAR (4.2) for compression and encryption, and finally backing those files up remotely. Thing is, RAR seems to ...
1
vote
1answer
333 views

How do I install lzip/plzip?

A former developer backed up all of our files using plzip. We no longer have the server he used to compress them and have not been able to find a program to decompress these files. We have Windows 7 ...
0
votes
1answer
364 views

How to create ZIPs with the content of every folder [duplicate]

I have several folders and I need to compress the content of each folder in a separate ZIP file. However, every ZIP should only contain the content of each folder and not the folder itself. The ...
1
vote
1answer
1k views

7zip - compress the contents of each folder in a directory

I basically want to compress each file in each folder, delete the original file and leave the folder uncompressed. I don't want to compress the whole folder, only the contents in it. That, with 7zip ...
-1
votes
2answers
140 views

How compress the compressed file in unix

Is it possible to compress the file that is already compressed? Example: Given a compressed file such as file.zip, would it be possible to gzip it into another compressed file in UNIX like this: ...
2
votes
1answer
1k views

Chrome data compression proxy for PC

Google Chrome recently introduced data compression proxy which saves bandwith up to %50 in Chrome beta. (https://developers.google.com/chrome/mobile/docs/data-compression) Sadly it is only available ...
0
votes
1answer
134 views

How to store many files in one file without using compression

If I have a large set of small files it takes Windows a long time to copy them (say five minutes) due to the overhead per file. If I wrap them up in a container it transfers them much faster (say ...
-3
votes
1answer
540 views

Compress text file to tar.bz2 format on Ubuntu

How can I convert a sample.txt (uncompressed) file to sample.tar.bz2 format using Ubuntu 10.04 command shell?
0
votes
1answer
433 views

COMPACT /U command does not decompress large 25GB file

I have a 25GB file that was incorrectly set as NTFS-compressed because the directory where it is had been marked as compressed when it was created. I am trying to decompress it. The file is currently ...
1
vote
3answers
571 views

Check if HTTP calls are gzipped

Assuming that I have an application server (Linux) running on port 80, how can I make sure (with tcpdump, I guess) that all incoming requests are gzipped and all responses are gzipped as well? Also, ...
0
votes
1answer
79 views

Force gpg to use compression?

Odd situation, and I won't go into details about why our present circumstances require it. But, I'm looking for a way to force gpg to use compression. My testing is suggesting that the following ...
4
votes
4answers
4k views

Recursively unzip files where they reside, then delete the archives

I goofed up a setting on the backup software I use. Normally I would have the files from a network share get loaded into a spare drive, compressed into zip folders, then sent off to the offsite hub. ...
10
votes
1answer
10k views

How does 'dictionary size' affect compression?

I know that higher size may lead to better compression ratio and vice verca. But is there a way I can decide better?.. since there are so many choices So far I've noticed dictionary size ≈ file ...
1
vote
2answers
141 views

Size of the compressed image file deteriorates with usage

I have created a VDI file using VirtualBox and need to upload it with compression for other to access. The more I use the virtual machine, the less the compression happens. There is not much of ...
1
vote
1answer
2k views

Video compression with ffmpeg - Constant quality

I am trying to compress videos of 10 seconds at different bitrates with ffmpeg. My aim is to obtain the same video at different qualities (from very low to very high). I don't want to touch audio part ...
-1
votes
2answers
587 views

Looking for a way to compress, encrypt, split, and upload data on Linux for backups to multiple clouds

As the title says, I'm looking for a way in Ubuntu/Linux to compress, encrypt, split, and upload data for backups across multiple clouds. I have grabbed multiple cloud accounts for free ranging ...
1
vote
1answer
2k views

avconv mkv to mkv with audio compression bug

In order to make quality tests, I would like to compress the audio part (to a low bitrate) of a matroska file without damaging video. Audio codec is AAC and video codec is H264. I am using avconv on ...
1
vote
2answers
122 views

How to extract such a compressed file?

I have been asked to extract a ZIP file having in it 3 tar files and each tar file contains around 3000 gz files. I had to extract the main ZIP file first then extract the tar files second then ...
0
votes
1answer
510 views

Windows: Automated PDF compression (Hot folder)

In Windows, is there a way to monitor a folder and automatically compress a PDF that is placed in it? (by compression, I mean make a PDF smaller (I.e. not zip it), similar to using the reduce file ...
0
votes
0answers
70 views

How to compress 2 (apple) disk images of different backups of the same drive?

So I have backed up my Macintosh HD at different instances to DMG files. I would like to compress them but when I try to make an archive it simply compresses each image, without recognizing the ...
0
votes
1answer
444 views

Differences between DMG and various Zip-like formats?

For my everyday work, I have a few DMG files that I keep on cloud storage. At the beginning of the day, I download my DMGs, convert them from Compressed to Read/Write using Disk Utility (OSX). At ...
1
vote
0answers
334 views

Compressing files over the network with WINRAR - read error

I have 3.6 TB of backup files on a NAS that need to stay together (they are a full and a months worth of incrementals - the latter is only useful with the former) - but I need to move them off the NAS ...
0
votes
1answer
44 views

What is “crossflow compression”?

I came across the term "crossflow compression" several times while reading about WAN optimization techniques. The only elaboration I've seen is that it refers to "compression across various flows", ...
0
votes
2answers
4k views

Zip many files into several archives

Running Linux. I have a directory of around 150 large CSV files; simply doing a zip -9 on them results in a monolithic file that is still too large. I would like it to simply zip them in maybe four or ...
0
votes
3answers
235 views

Untar multiple files at once?

I'm on Windows 7 and have a number of .tar files with the following names: .tar-aa .tar-bb .tar-cc ... The tar files contain a large backup directory which is broken up into chunks of 250MBs each. ...
-1
votes
2answers
164 views

Compress a remote folder in Linux

I'm a Linux newbie and I'm trying to zip a folder which exists on a remote host and export it to another remote host. A quick Google search lead me to tar/gzip and rsync options but I'm not sure how ...