We Will Serve No Algorithm Before Its Time
[ No. 18 - April 1998 ]
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Things That Are New
Realaudio encoder 3.1 was recently released and it seems to
sound better! Available on their website
<www.real.com>.
Perhaps in a latent response to Microsoft's acquisition of
V-Xtreme, Real Networks also announced the acquisition of Vivo
Software, Inc. This is unlikely to have any effect on Real's
audio quality, however RealSystem users may find in the near
future it improves the visual image you send with your music.
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Recently it was brought to our attention that a tutorial on the
much-touted MP3 format would be useful. Why MP3? Well, it's the
"People's Encoder." Unlike other proprietary formats (such as Dolby
Laboratories' AC-3; the guts of Liquid Audio and RealAudio) MP3 is an
authentic open standard. It's not licensed and owned by a privately
held company. Anyone can use it.
The MP3 codec "sounds" better too. And, because it's an open standard,
MP3 can be used, hacked and modified to perform in pretty much any
Internet audio application. How can this be? I can have it for free
and it's a superior product? Why don't I know about this? That's what
we're here to find out.
The scientific name of the MP3 audio compression algorithm (codec) is:
MPEG 1 (and 2), Layer III. MPEG stands for Moving
Pictures Expert Group, a bunch of honest-to-God scientists under the
joint direction of the International Standards Organization (ISO) and
the International Electro-Technical Commission (IEC). The MPEG group
is responsible for implementing standards for the coding of "moving"
pictures and audio. MP3 was specifically designed for "good" quality
audio compressed for transfer over lower bitrates (ie, phone lines).
Layer II wouldn't compress below 32kbs and that meant 28.8kbs modems
weren't going to be fast enough to actually stream realtime audio.
Soundfiles were simply too big to fit through that little telephone
connection. MP3's compression makes it possible to not only stream audio
over a 28.8kbs line, but also provide near-CD quality at higher bitrates
in a download-and-play environment. The real beauty of MP3 is that it's an
approved industry standard available to anyone. A "for-profit"
organization (say, Microsoft) can purchase the specifications from the
standards commitee and create their own player and encoder with
attendant features, or an individual (say, you!) can download any number
of shareware applications and create their own streaming audio files on
a personal website. This is what "open-standard" is all about.
MP3 Web Resources
There are resource sites dedicated to MP3 on the web. Here are a
few we suggest you take a look at.
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Let's take a quick look at the current state of MP3 encoders.
Fraunhofer Institute for Software and Systems Engineering, which created
basic MP3 compression software, has forced the freeware applications
which were using its software without permission to remove these
unauthorized copies from the net. Windows users can, for a fee of
around $200, purchase the Fraunhofer code and enable many of the
freeware front-ends. They can also use another application, mpegEnc, to
create higher-bitrate (for download-then-play) files. For information on the
Fraunhofer code, email
<layer3@iis.fhg.de>.
Macintosh users who have a
copy of SoundEdit16 (available for $419 at
<www.macromedia.com>) can
freely download and use the ShockWave Audio (SWA) export plug-in to
easily create files at all bitrates. In this column, we're going to
take you through the process to create a web-ready near-CD quality 112kbps
MP3 file with mpegEnc. So let's download it and fire it up.
We're going to assume that, like us, you have access to a PC running
Windows95/NT with a sound card (such as a Soundblaster). A 100MhZ Pentium
or better with 32MB (or more) of memory is recommended, as slower
computers may have you nodding off at the keyboard while it sluggishly
encodes your music -- or worse, it just plain doesn't work. A great
resource for Windows encoders is
<www.layer3.org/software/encoders.html>. MpegEnc is freeware and only
takes a few minutes to download over a 28.8k modem connection. Unzip
it, and make sure you can launch the extracted MPG.EXE application.
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PREPARING YOUR AUDIO FILE
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First, choose and queue up an audio excerpt of about 10 seconds to test
with. Select a clip which is representative of the dynamic range and
instrumentation. This way you'll be able to become comfortable with the
encoding process, quickly trying out different encoding options and hearing
the different results.
Most MP3 encoders don't encode in real time. You first must encode to a raw
WAV or AIF file, and then use the encoder to compress that to MP3.
This allows your computer to do its best while compressing, deciding
which pieces of the music aren't needed. Real time encoding limits the
quality of the final compressed file to how fast your computer can
think -- something you want to avoid unless you have no alternative (such
as live broadcasts).
Ok, make sure you've got you source (cassette, DAT, live, etc) plugged
into your sound card's line input and set your levels. If possible,
throw a compressor into the chain and get the highest level you can while
avoiding peaks into the red danger zone. You can then use a program (we
use CoolEdit95 <http://www.syntrillium.com/cool.htm>) to create your WAV
file. If you are encoding directly from a CD in your CDROM drive,
mpegEnc allows you to bypass this step and compress directly!
Launch the encoder application and select the WAV file as your
input file (or source). Choose the bitrate you'd like to compress
your clip down to: we're using 112kbps. Make sure "Layer III" is
selected in the "Compression Layer" option. Your resulting output
file will be named file.mp3, where file.wav is your source. Click
"Encode" and go make yourself a hot cup of coffee while it does its
work. Macintosh SoundEdit16 users will choose the "SWA" option in
the Xtras menu to set the desired bitrate and then select the "SWA
File" option in the Export menu (under the "File" menu) to export
it to an SWA/MP3 file.
You are publishing your work to the web and want your audience to have
the best experience possible listening to it. We FezGuys always test our
soundfiles before placing them on the web, and you should too! Choose a
player, test your bouncing baby MP3 file, and recommend it on your web site
along with your music. We're using WinAmp, available from
<www.winamp.com>.
If you are Mac-based a version is available at
<macamp.lh.net> (Power Mac
only). Spend some time trying other players out there (check our MP3
Resources sidebar for where to find them) and compare features and
ease-of-use yourself.
Just because it's an MPEG encoder doesn't mean that they all create
compressed audio files of the same quality. The technical wizardry
behind compressing the ones and zeroes of your music into fewer ones and
zeroes is a complex art. Why pay money for an encoder when there are
freeware versions available? A company's staff of well-paid geeks and
scientists are going to create an encoder which not only creates a
better sounding file, but also is quicker, and even comes with support
if you have problems! Also evaluate whether it's worth a one-time
investment which will result in an ongoing payback of spending time in
the studio rather than drinking those cups of coffee staring at your
screen as it compresses.
There is a running reputation amongst the music industry folks
associating MP3 with pirate sites getting sued by organizations
such as the RIAA. As it has been said, a tool is only as useful as
s/he who wields it-- your task is to wield MP3 well, legally, and
help dispell this association. The more people who apply MP3 in a
productive useful way promoting their work in a legal way, the more
accepted MP3 will become to the industry as a whole.
After spending last month answering our questions backlog, we're taking
this month off! Send us your questions/comments to us at
<fezguys@fezguys.com>
or join in our community areas at
<www.fezguys.com>
Don't forget to share your successfully encoded MP3 music with the world!
We do the hokey pokey when you get involved in the online community.
Visit us at: <www.fezguys.com>.
