Compress a large 4GB file to 1GB

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pbjja Posted messages 51 Status Membre -  
eriiic Posted messages 24581 Registration date   Status Contributeur Last intervention   -
Hello,

I am looking for how to compress a file of size 4.5 GB down to a maximum of

1.5 GB, for example.

I have WinRAR and WinZip, but honestly, I can't compress it that much.

Yet, I have already downloaded a compressed file; see the photo here

http://pbjja.pagesperso-orange.fr/telechargement/ccm.JPG
Configuration: Windows Vista Premium Authentic Intel Core Duo T2250 1.73GHZ 500 Go Hard Drive 3Go RAM DDR2 (533Mhz) 15.4" WXGA TFT TruBride HD TOGO Screen Nvidia Gforce 7300 Turbocache Multi DVD (dual layer) PCMCIA 5 in 1 card reader Ethernet Wifi

13 réponses

JFS77 Posted messages 437 Status Membre 70
 
I think you don't want to understand what is being said.
An ISO file contains a certain number of files.
It's these different files that are compressed. Some files are very easily compressible and others are not. So for certain types, you will achieve more than 50% compression and for others, less than 5%.

If you don't want to understand what others, including myself, are explaining to you, then program yourself a miracle software; maybe you'll win the Turing Award...
8
pbjja Posted messages 51 Status Membre 7
 
you still see a lot of pointless chatter.
I can understand that you don't know such a program
so let others respond and give a real answer
and I also understand that some files are easier to compress than others. Please don't respond anymore, thanks for the forum not turning into an endless discussion for nothing.
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Nabla's Posted messages 20731 Status Contributeur 3 228 > pbjja Posted messages 51 Status Membre
 
a little respect!

it's not just talk, he's telling you the truth: the size of your compressed file depends on two things: the content to be compressed, and the compression algorithm.

if you compress text, you will save a lot more space than when compressing a video!

so be more specific in describing what you are compressing, what your ISO contains, and you might get the answer you are looking for....
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biboo_ Posted messages 1462 Status Membre 106 > pbjja Posted messages 51 Status Membre
 
Absolutely agree with Nabla's.
The problem is that not all data is compressible (especially already compressed images..).
In short, unless you have ONLY text files, going from 4GB to 1GB is a miracle.
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Thetutub21 Posted messages 206 Status Contributeur 48
 
It depends on the content of the ISO. If it’s a game installer, for example, the data on the CD is likely already compressed. A second compression won’t give you more than 4 or 5%.
If you want to get 5% instead of 4, try 7-zip, but don’t expect miracles.
2
pbjja Posted messages 51 Status Membre 7
 
Hello again everyone...

There's no need to respond if you don't know the answer.

This question is here because it is possible to do this, I repeat:

I already have an ISO file that is compressed to 1.5 GB. Once decompressed, it results in a DVD ISO of 4.5 GB.

So if you don't know the real method, please don't respond, thank you (the pointless chatter tires me out, everyone would agree).
Also, if you think you know the method, try it out at home before suggesting it to me.

Thank you

(A good CCM is a well-thought-out and tested response before suggesting, then we wonder why we get lost in forums because of whom? Guess?)
2
Darkito Posted messages 1191 Registration date   Status Membre Last intervention   545
 
Hello,

Could it be a Wii game ISO?
It is indeed possible to "scrub" certain games to compress them.
So it’s not WinRAR that does it directly, but software like WiiScrubber
--
Tøƒ
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pbjja Posted messages 51 Status Membre 7
 
do you want this photo at the following link

http://pbjja.pagesperso-orange.fr/telechargement/ccm.JPG

if some people can do this, it is indeed possible to compress more

I have the compressed file at 1.5 GB which decompresses to 4.5 GB

we just need to find the software, there you go

I’m not asking for the impossible but I have the example so it is possible…
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eriiic Posted messages 24581 Registration date   Status Contributeur Last intervention   7 281
 
Good evening,

If we follow your reasoning, then the 4.5GB file compressed to 1.5GB should be compressible again by a factor of 3, bringing it down to 0.5GB. If that were the case, RAR would be garbage because it would have compressed by a factor of 3 when it could have done so by a factor of 9...
A file is compressible if it has a lot of repetitions (basically), and once compressed, there are no longer these repetitions that would allow for the same rate.
Moreover, a file compressed multiple times will eventually take up more space than the previous generation.
Eric
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pbjja Posted messages 51 Status Membre 7
 
darkito simply answered my question, thank you again darkito.
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biboo_ Posted messages 1462 Status Membre 106
 
Okay, it's a Wii game.
I understand why there was no precision..
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eriiic Posted messages 24581 Registration date   Status Contributeur Last intervention   7 281
 
Out of curiosity, if you can test both compressions (rar with and without WiiScrubber), could you please give us the sizes obtained?
eric
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Thetutub21 Posted messages 206 Status Contributeur 48
 
What type of file do you want to compress?
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pbjja Posted messages 51 Status Membre 7
 
file is iso, archive type winrar
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Thetutub21 Posted messages 206 Status Contributeur 48
 
The 7zip format offers a better compression rate than its counterparts in .zip, .rar, and even .bz2.
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Thetutub21 Posted messages 206 Status Contributeur 48
 
It's possible, I agree, but only for certain files: bmp or pict images, wav or aiff sounds, text files that are not already compressed. What does your ISO contain?
I also advise you to take a look at this page: compression, which will allow you to learn a bit more about compression and understand that it's not just about reducing size.
Have you tried compressing your file to .7z using the software 7-zip?
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pbjja Posted messages 51 Status Membre 7
 
this is already the beginning of an answer.
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