Audio Formats for the Web
January 31, 2000
In my
previous article,
I explained different audio and musical formats (including
MIDI, RealAudio, MP3, etc.) and how to include them in Web
pages in various ways, from simple embedded
"background scores" to scripted interactive sound effects.
I also covered the basics of streaming media there. If all
that isn't enough, I also covered various Internet audio
topics in my
Web Audio Workshop series, including how to select the
most appropriate file format, and how to distribute music
online. That material is mostly still valid, so any in-depth
discussion of the various file formats here would be
redundant. I'll restrain my loquacity (this time), and
confine myself to a quick distinction between streaming
and non-streaming formats.
Streaming allows the receiving system to start playing a
file before it has been fully downloaded. Data is received,
placed in a buffer, then played on the receiving machine
even as more data is being received. Streaming has two
advantages. First, it allows a user to listen to a sound
file (or view a video file) without waiting for a lengthy
download. Second, it allows for live or continuous
broadcasts over the Net, in the manner of a radio or
TV station. Traditionally, streaming media has been a
lower-quality format, but there is no inherent reason why
this must be. One of the reasons streaming media were
developed was because everyone had pee-wee bandwidth. Now
that a substantial number of people have the new
high-bandwidth services, many content providers are
offering streaming files in higher-quality formats, and
this trend is sure to continue. For example, RealAudio
allows you to choose one of several quality levels when
you create your files, so you can post different versions
on your site, and let visitors choose the one that befits
their bandwidth.
The offerings of
RealNetworks are the
best-known of the streaming formats, with
Microsoft and Apple's
QuickTime
nipping at its heels. But there are quite a few others out
there as well.
Xing StreamWorks
is a streaming format that's been around almost as long as
RealAudio, but somehow never caught on as they did. Another
of note is
Liquid Audio,
which offers a complete end-to-end music distribution system
which includes not only a way to deliver sound over the
Internet, but ways to prevent copyright infringement and
track payments due for music downloaded through the system.
Streaming media is appropriate either for continuous
broadcasts, or for situations where you want instant
gratification. It's also good for situations in which you
don't want the user to save the file - you just want to
give them a sample. If you want the user to be able to
save the file, and trade it with their friends (or pass it
on to a record company exec), then simply use a downloadable
file.
Of course, just as with any other files, sound files of
any format can simply be posted on a Web site for users
to download. The large size of audio files has always been
a constraint, however, which led to the development of
various compressed formats, the most popular of which is
MP3. MP3 files use a lossy compression scheme. They're quite
small, and the audio quality is good, although not quite up
to CD standard. For distributing music to end users, the
best way is still to mail them a CD (or better yet, a DVD).
But for distributing "promotional" copies of songs, MP3 is
the way to go.
Web Audio 2000
Web Audio 2000
Time for a Timeline
|
