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Exhaustive Data Compressor Comparison
crazyeyes writes "This is easily the best article I've seen comparing data compression software. The author tests 11 compressors: 7-zip, ARJ32, bzip2, gzip, SBC Archiver, Squeez, StuffIt, WinAce, WinRAR, WinRK, and WinZip. All are tested using 8 filesets: audio (WAV and MP3), documents, e-books, movies (DivX and MPEG), and pictures (PSD and JPEG). He tests them at different settings and includes the aggregated results. Spoilers: WinRK gives the best compression but operates slowest; AJR32 is fastest but compresses least."
Nothing to see. High compression = slow and low compression = fast. umm duh?
I never would have guessed that there was a tradeoff between the quality and speed of compression! No way! Next they'll be saying things like 1080p HD offers quality at the expense of computational power required!
Screw speed and size reduction. All I want it compatibility with other OSs (i.e., fewest things that have to be installed on a base OS to use it). For that, I'd have to say Zip and/or gzip wins.
So that's why smaller computers are slower, right?
I fill an old station wagon with backup tapes, and then put it in the crusher.
Not every software achieves maximum efficiency. It is perfectly imaginable that a compressor could be slow and bad. It is nice to see that these compressors did not suffer that fate.
as its slashdotted
this site
http://www.maximumcompression.com/
has been up for years and performs tests on all the compressors with various input sources, much more comprehensive
yep, looks like they're using WinRK on the fly to decompress the website from storage
I read this earlier today through the firehose. It was interesting, but the graphs are what struck me. It seems to me all the graphs should have been XY plots instead of pairs of histograms. That way you could easily see the relationship between compression ratio and time taken. Their "metric" for showing this, basically multiplying the two numbers, is pretty bogus and isn't nearly as easy to compare. With the XY plot the four corners are all very meaningful. One is slow with no compression, one each good compression/time, and the sweet spot of good compression and good time. It's easy to tell those on two opposing corners apart (good compression vs good time), where as with the article's metric they could look very similar.
Still, interesting to see. The popular formats are VERY well established at this point (ZIP in Windows and Mac (stuffit seems to be fading fast), and GZIP and BZIP2 on Linux). They are so common (especially with ZIP support built into Windows since XP and also built into OS X) I don't think we'll see them replaced any time soon. Of course, with CPU power getting cheaper and cheaper we are seeing formats that are more and compressed (MP3, H264, Divx, JPEG, etc) so these utilities are becoming less and less necessary. I no longer need to stuff files on floppies (I've got the net, DVD-Rs, and flash drives). Heck, if you look at some of the formats they "compressed" (at like 4% max) you almost might as well use TAR.
Comment forecast: Bits of genius surrounded by a sea of mediocrity.
Nice comparison, but there's really only two that matter (at least on PCs):
ZIP for cross-platform compatibility (and for simplicity for less technically-minded users).
RAR for everything else (at 3rd in their "efficiency" list, it's easy to see why it's so popular, not to mention ease of use for splitting archives, etc).
"Nothing strengthens authority so much as silence." - Charles de Gaulle
This is a poor article on several points. First, the entropy of the data in the files isn't quantified. Second, the strategy used for compression isn't described at all. If WinRK compresses so well on very high entropy data, there must be some filetype specific strategies used.
Versions of the programs aren't given, nor the compile-time options (for the open source ones).
Finally, Windows Vista isn't a suitable platform for conducting the tests. Most of these tools target WinXP in their current versions and changes to Vista introduced systematic differences in very basic things like memory usage, file I/O properties, etc.
The idea of the article is fine, it's just that the analysis is half-baked.
What's the point of compressing JPEG,MP3,DivX etc since they already do the compression? The streams are close to random (with max information) and all you could compress would be the headers between blocks in movies or the ID3 tag in MP3.
the most interesting thing about text compression is that there is only about 20% information in the english language (or less). yes, that means that 4/5ths of it is meaningless filler. filled up with repetitive patterns. as you can see, i really didn't need four sentences to tell you that, either.
i wonder how other languages compare, and if there is a way to communicate much more efficiently.
7-zip cribsheet:
weak on retarded things to zip like WAV files (use FLAC) mp3's, jpegs and divx movies.
7zip does quite well in documents (2nd) and ebooks (2nd) 3rd on MPEG video, 2nd in PSD
also i expect 7zip will improve in higher end compressions settings, when possible i give it hundreds of megs and unlike commercial apps 7zip can be configured well into the "insane" range
Snowden and Manning are heroes.
TAR is not a compressor.
TAR for compression? I woulda thought you were trolling if you didn't have LHA up there. Too bad you're anonymous, you'll never get to find out how unqualified you are for participating in this discussion.
"Old man yells at systemd"
See also: the Archive Comparison Test. Covers 162 different archivers over a bunch of different file types.
It hasn't been updated in a while (5 years), but have the algorithms in popular use changed much? I remember caring about compression algorithms when I was downloading stuff from BBSs at 2400 baud, or trading software with friends on 3.5" floppies. But in these days of broadband, cheap writable CDs, and USB storage, does anyone care about squeezing the last few bytes out of an archive? zip/gzip/bzip2 are good enough for most people for most uses.
Repton.
They say that only an experienced wizard can do the tengu shuffle.
It seems odd that they didn't include executables/dlls in the comparison (where maxmumcompression.com does). I also find it odd that they are compressing items that normally don't compress very well with most data compression programs (divx/mpegs/jpegs/etc). I'm guessing this is why 7-zip ranked a bit lower than most.
I did some comparison last year, and found 7-zip to do the best job for what I needed (great compression ratio without requiring days to complete). It also doesn't take into account the network speed at which the file is going to be transmitted. I use 7-zipfor pushing application updates and such to remote offices (most over 384k/768k WAN links). Compressing w/ 7-zip has saved users quite a bit of time compared to winrar or winzip.
I would definitely recommend checking out maximumcompression.com (As others have, as well) over this article. It goes into a lot greater detail.
Er... did ya check out the comparisons? As you can see here here jpeg at least can be compressed considerably with Stuffit. According to this the program can "(partially) decode the image back to the DCT coefficients and recompress them with a much better algorithm then default Huffman coding." I've no idea what that means, but it does seem to be more thorough and complex than what you wrote.
So they've compressed it to 11. I'd say that's a step forward.
Even it the amount of additional compression is insignificant, ZIP, RAR, etc. are still very useful as container formats for MP3, JPG, etc. files since it's easier to distribute 1 or 2 .ZIP files than it is 1000 individual .JPG files. And if you're going to package up a bunch of files into a single file for distribution, why not use the opportunity to save a few kilobytes here and there if it doesn't require much more time to do that?
"People that quote themselves in their signatures bother me" - athakur999
Back in the early/mid 90s I was pretty obsessed with data compression because I was always short on hard drive space (and short on money to buy new hard drives with); as a result I tended to compress things using whatever the format du jour was if it could get me an extra percentage point or two. Man, was that a mistake.
Getting stuff out of some of those formats now is a real irritation. I haven't run into a case yet that's been totally impossible, but sometimes it's taken a while, or turned out to be a total waste of time once I've gotten the archive open.
Now, I try to always put a copy of the decompressor for whatever format I use (generally just tar + gzip) onto the archive media, in source form. The entire source for gzip is under 1MB, trivial by today's standards, and if you really wanted to cut size and only put the source for deflate on there, it's only 32KB.
It may sound tinfoil-hat, but you can't guarantee what the computer field is going to look like in a few decades. I had self-expanding archives, made using Compact Pro on a 68k Mac, thinking they'd make the files easy to recover later, which didn't help me at all now -- a modern (Intel) Mac won't touch it (although to be fair a PPC Mac will run OS 9 which will, and allegedly there's a Linux utility that will unpack CPP archives, although maybe not self-expanding ones).
Given the rate at which bandwidth and storage space are expanding, I think the market for closed-source, proprietary data compression schemes should be very limited; there's really no good reason to use them for anything that you're storing for an unknown amount of time. You don't have to be a believer in the "infocalypse" to realize that operating systems and entire computing-machine architectures change over time, and what's ubiquitous today may be unheard of in a decade or more.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
I take it you come from a planet where very few people use Windows. Please, I'm curious to know, what are things like there?
The article conveniently forgets to mention whether the conpression tools are cross-platform (OSX, Linux, BSD) and/or open source or not.
That makes a lot of them utterly useless for lots of people. Yet another windows-focussed review, bah.
Give it am MD5 hash and a file length and it will compute all the possible files that could have produced the hash. Automatically filter our the invalid files and the set you're left with can't be that large.
There are places where the networks are not touching,and there are places where they are-Boeing's Lori Gunter
This reminds me of... pkunzip.zip
The saddest poem
While the main thrust of JPEG is to do "lossy" compression, the final stage of creating a JPEG is to do lossless compression on the data. There are two different official methods you can use: Huffman Coding and Arithmetic Coding.
Both methods do the same thing: they statistically analyse all the data, then re-encode it so the most common values are encoded in a smaller way than the least common values.
Huffman's main limitation is that each value compressed needs to consume at least one bit. Arithmetic coding can fit several values into a single bit. Thus, arithmetic coding is always better than Huffman, as it goes beyond Huffman's self-imposed barrier.
However, Huffman is NOT patented, while most forms of arithmetic coding, including the one used in the JPEG standard, ARE patented. The authors of Stuffit did nothing special - they just paid the patent fee. Now they just unpack the Huffman-encoded JPEG data and re-encode it with arithmetic coding. If you take some JPEGs that are already compressed with arithmetic coding, Stuffit can do nothing to make them better. But 99.9% of JPEGs are Huffman coded, because it would be extortionately expensive for, say, a digital camera manufacturer, to get a JPEG arithmetic coding patent license.
So Stuffit doesn't have remarkable code, they just paid money to get better compression that 99.9% of people specifically avoid because they don't think it's worth the money.
Does my bum look big in this?
Wow, are you speaking beyond your ken. When you say "some form of LZW compression", you should have said "some form of LZ compression" - either Lempel and Ziv's 1977 (sliding window) or 1978 (dictionary slots) papers on data compression by encoding matched literal strings. LZW is "some form" of LZ78 compression which, apart from GIFs, almost nobody uses. It's too fast and not compressy enough. Most things use LZH (LZ77 + Huffman), specifically DEFLATE, the kind used in PKZIP, firstly because the ZIP file format is still very popular, and because zlib is a very popular free library that can be embedded into anything.
Fax machines use a static Huffman encoding. They've never used run-length encoding. Run-length encoding is nothing compared to how efficiently LZ77 or LZ78 would handle pretty-printed XML.
Compression algorithms vary on both their compression and decompression speed. LZ77 is slow to compress and fast to decompress. Arithmetic coding and PPM are slow both compressing and decompressing.
Does my bum look big in this?
Things are less blue.
(And I'm not speaking of the sky)
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