[Originally appeared in New Orleans Beat Street magazine, May 2003.]
This
columnist’s spouse, the lovely and athletic Mrs. America, recently ran the Crescent
City Classic while listening to a tiny digital music player. But instead of
playing MP3s, she carried music encoded in Microsoft’s latest audio format.
Windows Media Audio (WMA) allowed her to store twice as much music in the player’s
limited memory, compared to MP3, while offering significantly better sound quality.
MP3
has become a household word, virtually synonymous with digital music (and music
copying). But the MP3 audio standard hasn’t changed since it was first established
a decade ago. During that time other technologies have come along, providing
better sound and smaller file sizes. We’ll survey some of these newer formats,
but first let’s take a look at MP3 and the principles behind audio compression:
CD
audio takes up around ten megabytes per stereo track minute; that’s a lot of
data, far too much to send across the Internet. So audio compression schemes
came into use, the most famous of which was established in 1993 by the Moving
Picture Experts Group (MPEG). MPEG-1 Level 3, also known as MP3, uses a process
called “perceptual coding” that reduces the amount of data representing an audio
signal, while still retaining the original sound impression.
One
of the quirks of human hearing is a phenomenon called “masking.” Masking is
when a loud sound at one frequency overpowers or obscures a weaker sound at
a different frequency. Perceptual coding assigns fewer bits to the masked parts
of a signal than to the prominent ones, assuming that listeners can’t hear many
parts of an audio signal, and won’t mind if those parts are missing.
It
works well but still causes a noticeable reduction in the sound quality at moderate
compression levels, and can easily introduce distortion (“aliasing”) at extreme
settings. An MP3 file compressed to 1/10th the size of the original
CD track sounds semi-okay, comparable to an FM broadcast. Compressing the file
down to 1/20th the original size sounds absolutely terrible, like
a lousy cell phone connection.
An
“improved” version of MP3, called mp3PRO, was released in 2001, but hasn’t caught
on. It’s not backwards compatible with original MP3, sounding noticeably worse
than garden-variety MP3 files on non-upgraded players. Moreover, the party that
administers the standard charges a hefty licensing fee to developers.
Concerned
there was a technology they didn’t control, Microsoft released their own alternative
to MP3 in 1997, called Windows Media Audio. Currently in version 9, also known
as “Corona,” WMA sounds noticeably better than MP3 (and mp3PRO) while providing
a much smaller file size. A CD track compressed to 1/20th its original
size in WMA sounds comparable to FM radio quality. That’s as good as, or better
than, an MP3 file twice the size.
The
Windows Media Player is bundled with every copy of the Windows operating system,
and if you don’t have the latest version you can download it free. There’s even
a Mac version. Microsoft also licenses Windows Media Technologies to developers
free of charge, accelerating its adoption in a variety of software and hardware
products. The Compaq iPaq portable player me and The Missus have, plays WMA
files as well as MP3s. Many other portable music players such as the SonicBlue
Rio and Creative Nomad also support WMA.
During
the last Christmas season we saw the first portable CD players that will play
a CD-ROM full of WMA files, as well as MP3 CDs, from manufacturers including
Dioneer, AVC, and (the now-bankrupt) SonicBlue. Again, the advantage is file
size: While you might get upwards of 200 MP3 songs on a CD-ROM, you could cram
300 or 400 WMA files on that disc, with equivalent or superior sound quality.
Twenty hours of music on a single CD is not too shabby…
Despite
their efforts and successes, Microsoft still doesn’t rule all parts of the galaxy.
Part of the reason is the open source programming movement, best known for the
Linux operating system. Open source has even spawned a compressed audio format,
which goes by the strange name of Ogg Vorbis. Ogg grew out of a dot-bomb called
iCast; the engineers kept working on it as their company crumbled, and convinced
departing executives to give the code away.
Defying
skepticism from some quarters, the Ogg team released an audio encoding standard
that competes well against both MP3 and WMA. The format is free for anyone to
use. Developers are encouraged to make improvements to the technology, as long
as they share their innovations with the world.
Ogg
compression and playback are now found in a number of software players, and
they’re developing a “reference platform” for Ogg hardware players. While we
haven’t yet seen any portable devices or CD players that actually include Ogg
support, it’s probably just a matter of time. Ogg sounds great at small file
sizes, and it’s a cool “underdog” format, in a field dominated by giant corporations.
There
are a number of other noteworthy audio formats, none of which are as widely
used for personal music as MP3, WMA and Ogg.
RealNetworks,
the originators of streaming, offers the RealMedia audio and video formats.
RealAudio encoding has improved greatly over the years, and can make a disk
file for desktop playback, much like an MP3. While commonly used for streaming,
RealAudio is not a typical choice for CD “ripping” – you’ll rarely find RealAudio
files in peer to peer file sharing networks such as Kazaa.
Apple
Computer has its own digital media platform, QuickTime, currently in version
6. Apple recently upgraded QuickTime Audio, licensing the Advanced Audio Coding
(AAC) technology from Dolby. Like the other latter-day formats, QuickTime Audio
sounds terrific. Although a lot of QuickTime Players have been installed on
both Mac and Windows computers, QuickTime’s biggest uses are in multimedia and
streaming, as opposed to music consumption.
The
last couple of years were a tough shake-out period for Internet and digital
music businesses; a number of once-promising audio compression schemes have
been abandoned along the way. Sony ATRAC3 is still used for MiniDisc recording,
but failed to catch on as an alternate to MP3. Liquid Audio was an early contender,
but the company finally tanked last summer. AT&T’s A2B Music and Lucent’s
ePAC formats are already distant memories. Nonetheless, work continues in many
quarters on improving audio compression. We look forward to hearing new, better-sounding
file formats with each passing year.
BIO:
Warren America has a disco mirror ball in his dining room, a skateboard ramp
in his back yard, and a patient, understanding wife.