[qwan]

The first time i saw uharc was... *censored*
The 200mb+ file would expand to 1.2 or 1.4 gb i am not sure long long ago.
That was the time i went searching for UHARC because i had the expaned files on my system but lost the original UHARC compressed file. I then found you previous site and downloaded the gui that time but i could only compress it to 499mb?? I just tried with winrar to compare and got the same compression from winrar. I used the highest settings in both. I even posted in the forum but i believe that it was frequented as often.
i just wanted to know how did they manage to compress that much and that was a selfextracting archive.
Infact later i found the original file and just extracted it just to see if can get the compression ratio but still i could only compress it to 499mb
Can you tweak soemthings in the commandline. If so why did you no include that in the gui

Recently my friend got another UHARC file which has around 800mb compressed to 200mb so he just called me up to tell me and ask me about UHARC. I asked him to compress the expanded file with winrar but he could get only 300mb approx so i am waiting for that file so i can see if i can get the same compression with UHARC which i downloaded again.
I mean are we missing something or is there some secret settings.
Please reply
Thanks in advance

[MuldeR]

The "highest" settings in the GUI should give you the best compression possible with UHARC!

Nevertheless so,e people use other ways to get smaller archives. For example they first convert Wave Audio files to MP3 or the convert Bitmpas to JPEG. In fact this is not compression, it is data reduction. This means, you get a loss auf quality!

Are you sure this archive you, are taliking about, there are no MP3 files that get converted back to wave? Could be one reason, why there comes some much data out of that small archive...

[qwan]

but is it possible to do that with UHARC because there was a batch file with it.
Just run it and it would extract.
I will check this new file and see; the censored file is to old i dont think i have a copy.
But i still remember it took quite a while for it to expand but then 1.2 gb would take quite a while so i am not sure.

So if that is the case it means that UHARC cannot give any more compression that the other compression suites around.
I think what ever compression is possible iwth files has already been figured out.
Thanks for the reply

[MuldeR]

UHARC does a 100% lossless compression. You cannot use it for data reduction, like Wave -> MP3

I think the Batch file, you used for decompression, did two things:
1) Call UHARC for extracting the files from the archive
2) Convert the MP3s (or whatever) back to Wave

[stryder]

Hi:)
I just came accross a .rar that when extracted came up with a .bat file that fully extracted the rest into an.uha,
The file compression was awesome:

This program download .rar was 77MB, but when extracted to the .bat file and it was run the file size was 525MB.

How would this be done ~edit~

Thanks

[MuldeR]

I think the data was packed with UHARC. That's why the compression ratio is so good

First step is compressing the files with UHARC (UHARC/GUI). So we get an UHARC archive. The problem is, most people don't have the software required to extract that UHARC archive. Therefore we need to give them two more files: The UHARC.EXE and some BAT file, which runs UHARC.EXE with the required commands.

Now second step: Put the UHARC archive, the UHARC.EXE and the BAT into a RAR archive. This is *not* done for compression! WinRAR will not be able to compress an UHARC archive any further. We do this in order to pack the three files into one. This way people only need to download one file instead of the three single ones.

Most people have WinRAR installed, so they can extract the RAR. Then they can run the BAT which will run UHARC.EXE and extrcat the files from the UHARC archive. Install completed


Note: Of course we don't need to use WinRAR in the second step. We can use another common archieve format as well (for example ZIP or 7Z)

[stryder]

Thanks for the reply muldeR
But there is no way I can see that UHARC will compress any file of this size 550MB to 78MB and I have tried the specific app I mentioned.

Whom ever compressed this app certainly knows alot more than I seem to:)
Most files after running .bat are .mst used with windows installer.msi, with Cab, Redist & Setup Folders.

Again thanks for your reply it is appreciated
stryder

[MuldeR]

1) Did you set dictionary size to the maximum?

2) Did you enable multi-media compression?

3) Try different compression modes: PPM (usually the best, but not always!), ALZ (might be better than PPM in some cases) and LZP (usually not very good)

4) Some types of data can be compressed better than others. For example we usually get a good compression with text files and program files. Compressing Audio, Pictures or Video is much harder. Files that are already a "compressed" format (for example JPEG, MP3 or DivX) usually can *not* be compressed any further.

[Riokushen]

mulder can you explain how dictionary works???

apparently the size is based on the amount of RAM we have on our comp. so if more RAM was available (eg 2GB ddr) would the compression be much better and achieve the amount stated above.

[MuldeR]

I'm not that expert about compression algorithms. What I can tell u is, that the dictionary specifies how much data the compressor (and of course the decompressor too) processes at the same time. A larger dictionary usually results in a better compression (for example when we process more data at the same time, it's easier to find similar parts). But a larger dictionary will also slow down compression and decompression! So in order to get the best compression possible, you should use the biggest dictionary size aviable. Nevertheless you can choose a smaller dictionary in order to speed things up.

Dictionary size is not depending on your computers RAM at all. If your RAM is too small to hold the whole dictionary (for example 128 MB of RAM and a dictionary of 256 MB) Windows will automatically swap the data to your hard-drive. This is nothing special, but of course it will slow things down.

Currently the largest dictionary UHARC supports is 32MB. There are other compressors that support larger dictionaries up to 192MB. But common compressors like WinZIP oder WinRAR use very small dictionaries (about 4 MB maximum).

[tadan]

firstly thanks for your effort

but really I tried this tool (or prog) and compared it with winrar
on compressing a game (mafia) the size of the game folder is 1.88GB
after compressing using this tool the net file was 1.4GB with 75% compressing (of course using the max compression and larges dictonary and cheking media detection)
then on using winrar the compression was 75% too
at last I found one differrence winrar did it in about 35 min, while this tool did it in at least 2 hours.

could you comprisse a file (of at least 1GB) and upload the it as an example, and if there are any ideas about increasing compressing ratio we are waiting for them

[MuldeR]

Again and for the last time: UHARC can't do magic. There simply is a limit to lossless file compression, or "entropy coding" to be precise. Some kinds of files contain a lot redundancy (or "low entropy") and thus can be compressed efficiently. This includes Text files and Executable code. Other files contain more or less "random" data (or "high entropy"), which means they cannot be compressed efficiently. At least not by an entropy coder! Most important that applies to "media" files (Audio, Video, Picture). No matter what archiver you use (UHARC, WinRAR, 7-Zip, whatever), there simply is a limit on (lossless) file compression! Computer games have a bit executable code and other stuff that compresses well, but most files are Audio files, Video files and Graphics that won't compress good. There is no "magic" trick. Entropy coding (alone) is just not what can achieve high compression here! You'd need a lossy compression scheme optimized for multi-media data here - such as MP3 for Audio, JPEG for Graphics or H.264 for Video. UHARC cannot deliver this...

See:
http://en.wikipedia....ntropy_encoding
http://en.wikipedia....rmation_theory)