A GUIDE TO 'SHN'

Move over MP3; purists demand ‘lossless’

by Steven Shayman

There’s a whole industry built around the MP3 data-compression format, but did you know that by using MP3s to burn music CDs, you lose part of the original recording as the data compressor does its work?

Such “lossy” compression schemes result in conveniently small data file sizes, but like audio cassette tapes of old, fidelity is lost each time you convert MP3s back and forth, to and from the CD-burnable .WAV file format, resulting in digitally degraded music files that become increasingly removed from the CD-quality benchmark to which listeners aspire.

The industry that relentlessly flogs MP3 probably doesn’t want you to know that it is possible to obtain truly “lossless” audio compression with very little trouble.

Shorten, otherwise known as SHN, is an audio compression scheme that can shrink and endlessly replicate music files without any loss of fidelity. The format is especially popular among traders of live concert recordings.

SHN was developed to compress audio files while having a way of verifying that copies are digitally exact. SHN was not developed for direct listening to music (although you can play back SHN files via Nullsoft’s versatile Winamp music player — see www.winamp.com — with the SHNAmp realtime SHN playback plugin — www.etree.org/shnamp.html ). SHN rather was intended to be an archival format for digital music.

Anecdotally speaking, SHN files seem to produce files that are between 50 and 65 percent of the original size. The fidelity of MP3 files, on the other hand, depends entirely on the sampling ratio you specify during the compression process. For example, on the popular MusicMatch music-file management software program, 64 kbps sampling produces supposedly “FM radio quality” files that are around 5 percent of the original file size, while 128 kbps — so-called “CD quality” — yields around 10 percent.

MP3 has good sound for such a small file size, but it is nonetheless a lossy compression scheme — a certain amount of data is lost and can never be recovered after the conversion. This data loss, to your ears, can sometimes result in a “swooshing” sound in the music, particularly during playback on good headphones or stereo speakers. For this reason, hard-core purists will argue that you should never make an audio CD from MP3 files.

The burgeoning online live music-trading community loves SHN (see sidebar), and turns to the “lossless” protocol for trading and downloading music — mostly of bands that allow recording of their concerts.

Trading is generally done in two ways: for those just starting a music collection or who are not so technologically inclined, traders get in touch with each other via Web sites and Usenet newsgroups to burn CD-Rs of live shows, which are then swapped via snail mail. A good primer on this is available at www.mcnichol.com/bnp. Also see the CD-R frequently asked questions at www.cdrfaq.org.

A second method is to download shows in SHN file format directly to your hard drive from a server online. This procedure requires a bit more technical savvy, however, including preferably a broadband connection, as well as familiarity with file transfer protocol, or FTP. But user-friendly FTP freeware programs, such as smartFTP (available at www.smartftp.com ) are out there to help the unsure among us.

However, downloading SHN files is possible in some cases via the more user-friendly HTML protocol — you can do it straight from the Web site, in which case you have to baby-sit the download. The number of files you can simultaneously download may be limited, depending on the Web site’s policy, Internet traffic and other factors.

After downloading SHN files onto your hard drive, you’ll want to burn a backup copy of those data files onto CD-R for safekeeping. Then, use the handy mkwACT freeware utility (see home.att.net/~mkw/mkwact/ ) to decompress them into listenable and CD-burnable .WAV format. You can also use mkwACT to extract SHN files directly from a CD, as it is also common for music traders to swap shows in unextracted SHN format. The utility also converts files from audio format back to SHN, or to and from MP3, if you wish — nothing is to prevent you from benefiting from the portability of MP3s or MiniDiscs or using your favorite music-file management programs like RealAudio and MusicMatch.

Note that .WAV file sizes are fairly large, so you’ll need to make sure you have an ample amount of free disk space.

An example: When I downloaded a February 7, 2002, show performed by the artist DJ Logic from New York’s Knitting Factory venue ( ftp://music.ibiblio.org/pub/multimedia/shnslingerz/logic ), one of the two sets weighed in at 409 MB in SHN format. After extracting with mkwACT, the resultant .WAV format file expanded to 681 MB. It’s been my experience that after downloading SHNs and extracting to .WAV, my computer’s hard drive fills up pretty fast, degrading performance. So, after saving the SHN and .WAV files to CD, I delete them from the hard drive and run a disk defragmentation program.

Be sure to always use Disc-at-Once (DAO) mode when burning live shows and SHN backup files instead of the Track-at-Once setting (TAO), which will leave an undesirable two-second gap between tracks on the CD-R. Among the better CD-burning software programs are EZ CD Creator by Roxio, and Nero.

If you go the download route, you can usually locate SHN files from open, unrestricted sources, including some public servers and Usenet binary newsgroups. In other cases, you’ll need to cultivate relationships with those in the music-trading community, who — if you’re lucky — will give you access to their private servers, where tradable shows reside on their hard drive, usually in SHN format.

A word to the wise: Take a look at etree. org — it’s the authoritative, one-stop resource site for great, detailed explanations of the issues discussed here.

Also note that the type of activity described here is quite aside from the ongoing debate about copyright and the lawfulness of a lot of the activity going on at popular peer-to-peer (P2P) Web sites like Kazaa and LimeWire. Much of the music available online in SHN format is of trade-friendly bands that allow the private, not-for-profit use of their work — there’s plenty of trading to be done without violating anyone’s copyrights.

A corollary understanding in the community is that artists’ commercially released work is never traded.

Bands with liberal taping and trading policies span an eclectic gamut from the Grateful Dead to Henry Rollins, Willie Nelson to AC/DC, Sonic Youth to Pearl Jam to various acoustic and bluegrass artists, and many others. Get more information at these sites: furthurnet.org/bandlist , btat.wagnerone.com , and db.etree.org/shncirc.

There are also some good reasons to steer clear of the most trafficked P2P file-sharing sites. Unlike the caring, conscientious music-trading community resources listed above, there is no quality control on P2P sites, which deliver files of unknown origin that may be corrupted. A whole host of legitimate, transparently administered and lovingly cared-for sites exist to allow you to indulge your music fix, so there’s no need to take the road most traveled.

And then there’s the next stage to consider — the newly emerging Free Lossless Audio Codec, or FLAC (see flac.sourceforge.net ). Like the open-source Linux operating system, FLAC is being shepherded by an active worldwide development community. FLAC advocates say the publicly supported, open-source format compresses CD-quality audio 5 to 15 percent better than SHN; supports higher, 24-bit and beyond audio resolutions (including the new DVD-A protocol); the ability to embed identification tags within audio files (useful for storing important information such as artist, song, source, recordist, etc.); hardware playback support; and real-time playback software for Windows, Mac and Linux operating systems.

There are currently far fewer FLAC files in circulation than SHN, but FLAC may supplant SHN in the future. Also, using FLAC even now requires no special technical prowess as it seamlessly integrates with most platforms and software already in use.

You may have noticed that most if not all the software applications mentioned here are for the Windows operating system, which reflects Microsoft’s predominance in the computing world. Macintosh and Linux users may be able to find Windows-emulator or Unix-utility programs at download. com or versiontracker. com , or by looking into Connectix Virtual PC products ( www.connectix.com/products ), which facilitate running Windows applications on Mac, Linux or OS/2 operating systems.

In any case, just remember there’s a world of enabling technology out there that allows music lovers to shed the prepackaged, limited solutions foisted upon us by the computer industry.