MP3/RealAudio
This section has answers to questions
about RealAudio / MP3 files
What is MP3? MPEG (Motion Picture Experts Group)
Audio Layer 3, to use its full name, is a standard for
encoding and compressing audio signals. It does a great job of
making audio files smaller without losing much quality.
"Perceptual audio coding" and "psychoacoustic compression" remove
parts of the signal that don't make much difference to the way we
actually hear sounds.
The upshot of all this is that it is now practical to transmit
high-quality audio over the Internet and store it on a hard drive.
Of course the decoding the signal to play it back requires a
computer, but the processing power for this will eventually be
included in standard hi-fi gear. And there are Walkman-sized
devices that let you play MP3 files away from the computer.
Are MP3 files legal? Some MP3 audio is legal and some is not. Only certain artists
(or their record companies) have agreed to make their music
available in this format. If you are unsure whether the MP3 audio
file you'd like to download is legal, you may want to check the
authorized Web site of the artist or label and look for any MP3
information.
What do I need to get started with
Audio online? If you don't need "near-CD quality," almost any computer with
a speaker will give you intelligible sound with many file types:
If you're not sure if you can play a given format, just click on
the link to hear it. The latest browsers offer a lot of audio
support, and will often let you know if you need additional
software, and even help you download and install it.
What do I need to play higher-quality
audio? These days, high-quality audio on the Web means MP3. Here's
what you need to get started with that format.
First, you need a suitably powerful computer. If yours was made in
the last few years it should be ok: minimum of a Pentium, Mac
Power PC, or comparable processor. And, since the files can be
quite large, it helps if you have a reasonably fast modem-56K,
ISDN, DSL, or Cable.
You also need a sound card and speakers, and special software.
There are a lot of choices here, from simple playback software to
systems that let you convert CD tracks or other audio input to
MP3. To find such software, we suggest you visit our download
area. Finally, you can buy a standalone MP3 player about the size
of a Walkman that lets you take you music with you. To find out
more about MP3 players, visit Afghan Bookshop and search for MP3
Players.
What do I need to know about audio
file types?
Different file types require different playback software, although
some players can handle more than one type. Some file types are
proprietary, that is, the software for them is controlled by one
company. Commonly used audio file types include WAV, MP3,
and RealNetwork's RealAudio (.ra).
How can I download an audio
file?
Steps for downloading depend on the Web site. Often it's as simple
as click and listen - some files play while they're downloading.
One important but often overlooked step is to note where on the
disk the file is being downloaded.
The path to the download folder is usually displayed in a dialog
box that appears while the file is being downloaded. If for some
reason you miss that, you start downloading the file again and see
where they intend to put it. Then stop the download and look
there.
If all else fails, search your hard drive with your computer's
Find command. In Windows, click the Start button and Select Find
> Files or Folders. With a Macintosh, press Command-F while
using the Finder. Enter whatever you can remember about the name
of the downloaded file, for example its file extension (e.g.,
"MP3") and start the search.
Searching FTP sites for MP3
Files
An FTP (for File Transfer Protocol) site is simply a place on a
network where people store files, typically for download by
others. There are a lot of public FTP sites on the Web, and many
of them store audio clips, especially MP3s. Leave the FTP box on
the AltaVista Search screen checked to search FTP sites. However,
many of them are "ratio" sites, which require you to upload files
before you can download. Typically the ratio is 4:1, meaning that
you can download four MB of files for every one you upload. To
upload files, you need an FTP program, which you can find on the
Internet at low or no cost. To download a FTP client application,
see bottom of this page.
What is "streaming audio"? Streaming audio, or streaming media, refers to a technique for
listening to audio files in such a way that they start playing
before the download is complete. It works by downloading and
storing enough of the file to act as a buffer, a reservoir that
will let the music keep playing if the transmission is briefly
interrupted. It's great because it lets you sample the audio and
decide whether you want to continue downloading or just cancel. It
also gives you something to listen to while you wait. Of course,
if for any reason the transmission slows too much, the buffer can
be used up, and the playback can sound choppy.
