MyBB Hacks

I've just archive a file using 7-Zip. Then I think I want to compare the result if I use WinRAR or WinZIP.

Here is the result:

File: .nrg
Size: 10,349 KB

Compressed file (using default settings):
7-Zip: 4,819 KB
WinRAR: 6,186 KB
WinZIP: 5,454 KB

Well, 7-Zip is the winner

7zip is my first choice too.

In terms of pure compression, PAQ8PX/PAQ8KX is probably one of the best.  It's unusably slow however, and it's not "asynchronous" (that is, decompression is just as slow as compression).

7zip's LZMA and perhaps UHARC are probably the best compression for general usage (the latter doesn't have much support though).

ZIP (deflate) is "old" and can be beaten by most newer algorithms at pretty much anything.  LZMA usually beats RAR, but RAR will sometimes give better compression due to having more filters (in particular, media files such as .wav, where LZMA has no filter); for text, RAR seems to beat LZMA, but 7zip's PPMd beats RAR.

I usually compress my code here using 7zip's PPMd.

Comparison I did a while ago:

Quote:XThreads script v1.10 - uncompressed = 210,215 bytes

RAR - WinRAR 3.90
Best compression (solid) = 41,578 bytes

7z - 7-Zip 9.13 beta
LZMA (solid) 128MB dict, 64 word size, 1 thread = 47,483 bytes
LZMA2 (solid) 128MB dict, 64 word size, 1 thread = 47,484 bytes
PPMd (solid) 256MB dict, 32 word size, 1 thread = 39,601 bytes

PAQ8
PAQ8KX Max compression = 30,432 bytes (took 1.9GB of RAM and 101 seconds to do the job)
PAQ8PF Max compression = 35,268 bytes (took 1.2GB of RAM and 2.7 seconds to do the job)

I've just do other test involving UHARC:

Format: .wav (RIFF Wave), 44.1 kHz, 32 Bit Depth, 2822 kbps Bit Rate
File Size: 42.1 MB

RAR (default): 14,312 KB
7-Zip (default): 11,558 KB
UHARC (-m3 / -m3 -md32768): 11,137 KB -> The winner here, but too slow......(?) (169.6 s)

RAR (Best): 14,304 KB (I don't know how to set this at its max settings)
UHARC (-mx / -mx -md32768): 10,622 KB
7-Zip (Ultra, PPMd, 256 MB, 32, Solid, 1 threads): 10,961 KB
7-Zip (Ultra, PPMd, 512 MB, 32, Solid, 1 threads): 10,676 KB
7-Zip (Ultra, PPMd, 768 MB, 32, Solid, 1 threads): 10,415 KB -> beat UHARC at this setting + faster.

I think my test above is not a 'valid' result, because I don't know much about how to set those software at the maximum settings

For WinRAR, just choose Best RAR, and tick the Solid compression checkbox.  Solid compression only is used if you're compressing more than one file though, so in your above case, it won't make a difference enabled or disabled.

32-bit (single precision float?) WAV is a bit unusual as a file you'd distribute - usually they'll be 16-bit, or in some not-so-often cases, 8-bit or 24-bit.

PPMd is designed for text compression, so I'm surprised how well it did with your WAV sample.  UHARC usually beats 7-Zip, but of course, at the expense of speed.  I'm also unsure if the algorithm is really optimised since it doesn't seem to have undergone as much development as LZMA, so maybe there's more speed potential in it.
RAR generally beats LZMA at media compression (see also this guy's comparison) - this probably also includes images, as well as already compressed data (LZMA doesn't seem to handle compressed data well - this issue was fixed in LZMA2 which can store uncompressed blocks).  I guess your example shows where RAR doesn't beat 7-Zip.

Yeah, I forgot to change the Bit Depth to 16-bit, Yumi

7-Zip is my primary file compressor now. Very good compression ratio and fast.

I have moved from Windows to Linux and then to Mac. When I was on Windows, I really liked 7-zip. It was very reliable and I always like open source.  Now that I am on Mac, I just use the built in finder zip utility.  It does the job and seem to work well for uploading files to the cloud.

I've just archived some backups using 7-Zip, most of the files are php and xls files:
531 MB -> 1.27 MB!

Amazing !

Depends on how much redundancy there is.
531MB is quite a bit - I'd suspect most of that would probably be large Excel files rather than lots of PHP scripts.
Large Excel file -> big data dump?  In which case, compression should do fairly well on it.

If what you mean by the redundancy is there are much the same files in the archive, yes, Yumi, there are much the same files in the archive.
For example, the files in folder 1 are the same as the files in folder 2, with some modified files.
And in those folders, there are some xls files. Most of the xls files are the same also, some of the xls files has been modified in the others folder. They are usual xls files. The average size is about 1.7 MB.
I just full backup those folders from my previous localhost.

I've tried using WinRAR to archive it, the result is about 122 MB archive file (again, 1.27 MB using 7-Zip).

For the 7-Zip and WinRAR, I just use the default setting (right click -> folder_name.7z/rar).