Compression decreases the size of data.

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4answers
40 views

how to verify whether a compressed .gz is corrupted or not?

I have many gz downloaded from the internet, and I would like to make sure they are not corrupted. Does the fact that I can open the archive with winzip on windows proves that everything is fine? I ...
4
votes
2answers
339 views

Is there a client impact to server side NTFS compression?

One of a our file servers at work is being compressed with NTFS compression. I've read about it being generally inadvisable on servers. But I've not found anything the states where the compression/...
0
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1answer
209 views

OpenVPN Bad LZO decompression header byte: 69

On Arch Linux I run OpenVPN 2.3.9 server and I get this error "Bad LZO decompression header byte: 69" I run the client on a rooted Motorola XT1039 android lollipop 5.1 and I use official "OpenVPN ...
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1answer
3k views

Disabling “System and compressed memory” (ntoskrnl.exe)

I am very exhausted by this. This program is destroying my computer. I have an ASUS G750 series laptop, which has 16gbs of RAM and a haswell i7 inside it. It is just a year old. I upgraded from ...
0
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0answers
9 views

How to save as a Video-TS-BUP using DVDShrink

Using DVD Shrink 3.2 I compressed a video that had been converted from MP4 using ConverXtoDVD, however after it was compressed it appeared in my G drive in a format that would not play rather -by ...
0
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0answers
21 views

How does motion estimation work?

I am trying to understand the basics of video compression. I have found many resources addressing this particular subject, but somehow, I haven't clarified it yet on my mind. How does motion ...
0
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1answer
16 views

How can I get dictionary size of 7z archive using comand line?

I've got an 7z archive, I've read manuals but couldn't find how can I get dictionary size of this archive using comandline?
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2answers
114 views

Guess compressability of a large file

I have a large file (~20 GB) and I want to quickly make an (approximate) estimate of how well it can compress. Searching for a program which can provide an immediate guess at the compressed filesize, ...
0
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4answers
70 views

How can I compress a large file on an already-full disk? [closed]

I have a full disk containing a large file that I want to compress to free up space. Most compression programs require me to have enough free space on the disk to store the compressed file alongside ...
2
votes
2answers
77 views

Measure ram usage in Windows 10

I'm currently writing a report of an application and I want to know its memory usage. Windows 10 has a nice feature that compresses memory that is not in process working sets in order to manage more ...
0
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1answer
72 views

Creating a ZIP file that extracts cross platform

I need to distribute a large (6GB+) file cross-platform. For practical reasons, I want to zip it down to 2GB+. I originally used Mac OS 10.11 to create the zip file using the Archive Utility. It ...
2
votes
2answers
384 views

Zip all uncompressed file in a folder in one line

I have a lot of text files that I want to compress. Each file must be compressed separately. But some of them are already compressed. How do I, in one line, compress all files that end with .txt by ...
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2answers
80 views

Use ISO instead of ZIP or RAR to store files?

I have been doing some backups of my old files and lately I was wondering if there is another method of storing and compressing files other than ZIP or RAR. In my case, I want to store various group ...
0
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1answer
32 views

What are the disadvantages of using ultra compression?

7zip offers an option for ultra compression but I'm guessing that it has some disadvantages (other than being more time consuming) or else it would have been the default option... So what are they?
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1answer
93 views

lossless video using FFmpeg ffv1 on jpeg images is not compressed but expanded

Is it possible for FFmpeg / ffv1.3 / mkv to create a lossless video is not larger than the sum of its parts (and if so, how) and if not, what is a good alternative to come close on size? The video ...
1
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2answers
9k views

How to extract .arc files

I downloaded a software from the internet which is in .arc format. How can I extract the files on MAC? The arc file is 4GB, but I believe it will be 30 GB when extracted.
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0answers
100 views

IIS vs httpZip (or other product) Compression

We're currently comparing httpZip compression software. Has anyone used this and can offer a comparison between that product and IIS? Is there a big savings for httpZip over IIS? If you aren't ...
7
votes
4answers
5k views

Missing send to “Compressed (zipped) folder” after 1511 update or drag+drop to .zip

After allowing the Windows 10 1511 update to be applied, all options have disappeared from the right-click "send to" menu, except for "Bluetooth Device". Additionally, I can no longer drag and drop ...
3
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1answer
44 views

How easy is to recover uncompressed data if one sector is damaged in a 7zip archive?

I have around 100,000 small files which I backup every few weeks. Because they are really small, write speed to my external 2.5" USB 3.0 HDD is really slow. In 7zip, I compressed them using ...
1
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0answers
21 views

How can throughput be greater than the bandwidth? Is this a valid reason?

I asked this question on networking engineers but it was closed as off topic since it wasn't for professional application. Hope it fits better here. I'm studdying for the CISSP secuirty exam and a ...
1
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1answer
56 views

Cut and Compress 4K Video?

I have a 20 second video which size in 4K which size is 125 MB. It is only about a defective electronic component so accuracy is not important. I want it much smaller. I have these options in VLC ...
2
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3answers
3k views

How can I use the Btrfs compression option when installing Linux?

I've been trying out the Btrfs with an SSD drive and like the compress option which is set in the fstab. However this only applies to the files created after I have installed the operating system and ...
-2
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1answer
46 views

Why is plain jar file compressed to 76% but after ProGuard shrink & obfuscate; it is compressed to 102% ?! How to fix?

I have a jar file of size 392 MB. I made another copy of it, so I have now two copies of the same jar file. For one of them I used 7-zip to compress it. It is compressed to 76% of the original size, ...
4
votes
2answers
73 views

Why do these PNG images differ so much in size?

I created a lot of tiles and each of my tiles is less than 2 KB except one which is 16.2 KB. It is very similar to another tile I created which is 1.48 KB. Yes, I'm nitpicking about the sizes here but ...
0
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1answer
31 views

TAR and compress a directory but skip compression on already compressed files

I want to TAR and compress a user's home directory as efficiently as possible. The problem is there are a lot of large and already compressed (gzip/bzip2) and hard-to compress files (binaries/data) in ...
1
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0answers
78 views

Archive Directory Using Zpaq

I am trying to setup a backup system for a server that I manage to improve upon the old system. I am choosing zpaq because it provided good compression with the old system using lrzip -z and because ...
0
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2answers
572 views

What happened to .gzip option in 7-zip?

I am not sure if this is just a coincident or not but I have recently upgraded my OS to Win 10. I noticed only now (after the upgrade) that the .gzip archive format is not available in 7-zip anymore....
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0answers
25 views

How to save compressed (batch processed) video files to the original folders using handbrake?

I use handbrake to compress/encode video files and I'm quite happy with the results. It gives me small file size with no quality loss. The problem is that when I batch convert multiple files from ...
0
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2answers
37 views

Edit executable file, instead of run, in Compressed Folder Tools

When I open a .zip file in Windows 10, and view it in its Compressed Folder Tools, I can open text files, Windows documents, etc. But for executable text files, like .bat or .js, the open option tries ...
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0answers
12 views

7zip File Compression Auto-Selection

When I'm zipping a folder hierarchy, I'd like 7zip to automatically detect whether a file in the folder tree is or is not already compressed, so that it automatically chooses whether to merely add an (...
1
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0answers
35 views

wget only new or updated files when the source files are compressed but the destination files are uncompressed

I would like to know how to wget files from a url which are stored with bz2 compression. However, I would like to only wget the new and updated files, relative to my destination, where the files are ...
0
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1answer
279 views

Uncompress bz2 file from command line on Windows

Is there any tool in the Windows command line that allows me to do this? Otherwise, is there any light and portable application that will allow me to? Related question, can I rename .bz2 extension to ...
4
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1answer
4k 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
3answers
1k views

Create multiple zip files that are not dependent on each other?

I want to compress a folder into multiple zip files of 50MB each but don't want them to be dependent on each other. When I use Winzip and use the split feature it creates one zip file and the others ...
0
votes
1answer
2k views

How do I compress a 200MB MOD video file?

My grandpa sends me this huge 200MB video file and asks me to compress it. I bet that there are many ways I can do this. For instance, just guessing some ideas: Use an online conversion tool (http://...
4
votes
1answer
27 views

Can compression of folder be undone when it comes to slow?

I know that compressing save disk space on my hard drive and I know that it is mutch slower for read a file. However I will compress the C:\Users folder. Personal files are stored on a SSD drive. ...
4
votes
2answers
2k views

Avoiding extreme fragmentation of compressed system images on NTFS

Problem explanation I'm storing windows disk images created with wbadmin on NTFS drive, and I found compressing then with NTFS compression gives 1.5-2× space conservation, still giving full ...
0
votes
1answer
99 views

Best data compression format available [closed]

I'm sometimes sharing big files (1 GB, Visual Studio C++ Solution) over the internet, but I have very very low upload speed. So, I'm trying to compress my data into the smallest file as possible. I ...
0
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0answers
53 views

Why is Encase disk image smaller than used space on source HDD?

I am using a forensic disk imaging tool to make an Encase (E01) disk image of a 4TB hard drive. 3.19TB of space is actually used on this disk. The resultant disk image is 2.82TB in size. No ...
0
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2answers
53 views

Extract .tar.gz file that has files with .gz extension

Using this question I 'zipped' the folder with thousands of images on apache server. This apparently changed the files inside the folder itself and zipped the files. But that's not the issue atm. I ...
2
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0answers
49 views

Is there anyway to reduce bandwidth usage of Skype for business?

We use a lot of 'Skype for Business' (i.e. the new Microsoft Lync), that I use while consuming expensive roaming data. Was wondering, if there are options (similar to various VLC clients) that lead to ...
1
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1answer
69 views

Which files and folders are compressed when using compact.exe /CompactOS

I am thinking of using NTFS compression (LZNT1) on my SSD using Windows 7, but I was a little unsure as to which folders would be a good candidate. I was aware that Windows 10 has introduced new ...
0
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0answers
23 views

7zip is creating solid .zip files. Cannot add/remove/overwrite to .zip files ad-hoc

I'm using 7zip as an archive creation tool. .7z files may be created as solid or nonsolid files. .zip files are supposed to be inherently nonsolid. I have ~5GB of hierarchal folder/file structure ...
1
vote
1answer
222 views

How can PowerPoint 2013 compress background images (not just inserted pictures) to reduce filesize?

I have a 10-slide presentation that is a whopping 234 Mb! This is because each of its slides has a high-resolution image as its background. (I tested this by temporarily setting all slide ...
13
votes
8answers
24k views

Why doesn't ZIP Compression compress anything?

A 398MB directory was only compressed to 393MB using 7Z and Normal ZIP compression. Is this normal? If so, why do people continue to use ZIP on Windows?
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0answers
15 views

What is the relationship between dictionary size and compression ratio? [duplicate]

For dictionary based compression algorithms, would there be any real benefit to having a very large dictionary ? In what cases can a large dictionnary be usefull : small or larger files ? Thanks in ...
0
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0answers
44 views

How to extract PPmD archive data in Ubuntu?

So I have a file called ppmdData with no extension, then when I use the file command on it, it says it is a PPMD archive data. When I run 7z x secret, I get an unsupported method error. Can anyone ...
0
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1answer
65 views

Extract Y-channel of every I-frame from MPEG4 movie as loslessly as possible

I'm working on a video tracking experiment and got stuck with videos that are quite badly compressed with the MPEG4 DivX 5x/6x codec. I'm fairly new to image formats, codecs and compression, but I ...
1
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1answer
74 views

Extract multipart rar, deleting parts as they are extracted

I have a multipart rar of 80GB unpacked. I have 5GB of free space, and every part of the rar archive is 2GB. What I'm looking for is to extract one part, delete it, extract the next, and so on, as to ...
1
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1answer
88 views

How to send a delta (differential part) of a large binary file over the Internet?

I have sent a large (>1GB) binary file to a friend over a slow metered data plan and now I need to send the second version of the same file only slightly changed. I want to send only the delta/diff-ed ...