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."

Comments

Screw speed, size reduction: gimme compatibility

[xxxJonBoyxxx]

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.

Re:Screw speed, size reduction: gimme compatibilit

[Nogami_Saeko]

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).

Poor article.

[FellowConspirator]

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.

Re:Poor article.

[RedWizzard]

I've got some more issues with the article. They didn't test filesystem compression. This would have been interesting to me because often the choice I make is not between different archivers, but between using an archiver or just compressing the directory with NTFS' native compression.

They also focused on compression rate when I believe they should have focused on decompression rate. I'll probably only archive something once, but I may read from the archive dozens of times. What matters to me is the trade-off between space saved and extra time taken to read the data, not the one-off cost of compressing it.

What's the point of compressing JPEG,MP3,DivX etc

[mochan_s]

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.

7zip

[Lehk228]

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

Archive Comparison Test

[Repton]

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.