Realtime Audio
The ability to receive audio signals in "real time" (as it is happening) is a
recent and rapidly growing development on the Web. We shall demonstrate some
applications with RealAudio Player
3.0 beta, a freeware realtime audio player
available for PowerMacs, Windows, and Unix systems from
RealAudio (a commercial version with
additional features is available from the same site). A
RealAudio FAQ is also available.
RealAudio Player
can function either as an independent application to
access realtime audio on the net, or as a plugin application that is
launched automatically by the Web browser when you connect to a site
transmitting a realtime audio stream.
Some Caveats
The present Mac version of the RealAudio Player
is only available for
PowerMacs running 7.x operating systems,
not older Macs running 680xx chips or earlier operating systems.
Furthermore, the transmission
of high quality
realtime audio on the network generally requires at least 28.8 kbaud modem
connectivity. You can still connect at slower speeds, but the
sound quality will be diminished. Over ISDN and faster connections the sound
quality can be quite high
from sites offering a 28.8 kbaud stereo audio stream if you use
version 3.0 of RealAudio Player
and
have stereo speakers on your computer.
The Timecast RealAudio Guide
A starting point for exploring realtime audio sites on the Internet is
the
Timecast RealAudio Guide
(Unfortunately, it is also one of those awful sites where content takes a
back seat to flashing lights and truly annoying commercial advertising
that makes loading extremely slow; thus, it serves as an excellent example of
how NOT to construct Web pages). From this
site, you can find a variety of News, Industry, Business, and on-line radio
broadcasts of all types, as well as special events
(sample special event:
the live audio feed from Space Shuttle missions can often be
found at
SPACEZONE). Assuming that
RealAudio Player has been
installed and configured to launch automatically from your browser, you can
explore a variety of sites simply by clicking and following the instructions.
Example: News and Information Soundclips
As an example, let us use the Timecast page to select an audio clip of
the lead story of the day from
National Public Radio
(NPR), and an audio clip
from the informative
Earth and Sky
daily radio thumbnail sketch. From the
Timecast RealAudio Guide,
select the "Daily Briefing" tab. On the resulting page,
click the buttons for "NPR Lead Story" under
"National/Global News" and "Earth & Sky" under "Entertainment".
Once you have made the selections, click the "Start" button to play the clips.
Example: Live Rock Radio from Sweden
The preceding example played a fixed soundclip.
A more powerful application is the transmission of "live" sound.
As an example, let us illustrate the use of "on demand" radio by
connecting to the live audio stream for a Swedish rock radio station, FM 105.5
"Bandit Radio". Use the browser to access the
Timecast RealAudio Guide
Select "Find the newest and best RealAudio sites", and from the resulting page
select "Rock" from beneath the "Music" heading.
This should bring up a scrollable menu of
rock-oriented radio stations; scroll down the page until the following entry:
Click on the highlighted link "Bandit 105.5 Rock" to bring up the main page of
the radio station (which, not surprisingly, is written
in Swedish). On this page there
is a link labeled "Lyssna paa Bandit genom realaudio!", which is Swedish for
"click here to hear the music" (well, it's a loose translation!):
Click on this link to launch RealAudio Player.
This should bring up
the following window
which will load data for a few seconds, play a voice blurb in Swedish, and
then launch the audio feed for the station broadcast (the DJ is Swedish but, as
is true the world over, most songs on rock radio are in English). This
audio stream will generally
remain on as long as the above RealAudio window remains open,
even if you go and do other things with the browser.
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