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MP3 - MPEG-1 Layer III (or MPEG Audio
Layer III)
MP3 was introduced as a part of the official MPEG-1
standard in 1992 and until today it is the most successful
audio-standard since WAV. The german Fraunhofer Gesellschaft
(FhG), which has developed this audio-compression still
holds the key patents the MP3-techology inherits. The development
started back in 1987 at the Fraunhofer Institut Integrierte
Schaltungen as project EUREKA EU147. The final compression
algorithm became later known as MP3. In April 1989 Fraunhofer
applied patent on MP3 in Germany and it became part of the
MPEG-1 standard in 1992. It was in january 1995 when Fraunhofer
applied patent on MP3 in America as well and it was granted
in November 1996. Using MP3-compression PC-users were able
to compress an ordinary music-CD to one tenth of it’s original
size - thus 12 hours of music could be stored on a recordable
CD that on the other hand could be played by a MP3-CD-player
or an ordinary PC. What made MP3 that popular in the end was
the online peer-to-peer program named Napster. Millions of
songs were exchanged every day via the popular program. That
was solely possible by MP3, because conventional formats such
as WAV or AU were way to big in size with similar quality.
MP3 also offered like WMA later the big advantage of being
streamingable (not all of the file has to be downloaded to
listen to it).
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WMA
- Windows Media Audio
Microsoft’s
respond to MP3, the Windows Media Audio-standard. As it is
part of the Windows Media package, Windows Media Audio 8 was
presented in early December 2000 and it is until now the best
Windows Media product.
Windows Media Audio among other things is firmly integrated
in Microsoft’s Windows Media Player.
Microsoft promises with this version almost CD-quality with
just a third of the source-file’s size.
Above all WMA offers the advantage that copyright-protected
songs cannot be published any further (Digital Rights Management).
That’s not the only reason why many music- and movie-corporations
meanwhile decided in favour of WMA instead of MP3. Like MP3
WMA is almost predestined for the internet by offering streaming
capabilities (see MP3 for details) both with WMA and WMV (Windows
Media Video).
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OGG
The
development of the OGG standard began in 1993, then known
as “Squish”. OGG was right from the start an open source project
and hence is free of any patents. It was designed as a substitute
for MP3 and WMA and by now it is almost as popular and well
known as MP3. Above all, the algorithm is still being developed
what is mainly due to its flexibility. Although the sound-quality
gets better with every further development the files are backwards
compatible and can be played with older players as well. Like
MP3 OGG offers encoding at variable bitrates. Using this compression
parts of the song are encoded with a higher compression than
others what depends on the source. Most times, this compression
goes along with squishy noises or even small interruptions.
OGG is also one of the very few formats that support multi-channel
compression. Surround-files could theoretically be compressed
with more than two channels. OGG is, like it’s predecessors,
streamingable and although the used player has to support
this feature, it’s one of many good reasons for OGG.
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VQF
It
was back in 2000 when another audio-standard was “given birth”
and since then struggles for the users’ favour. VQF however
suffers mainly of two things: first it is hardly known anywhere
and second it takes the PC about three to four times longer
to convert a song in VQF than in any other format.
At a bitrate of 80 kbps VQF promises the same quality MP3
does at 128 kbps - this would mean that VQF-files would take
30 % less space. Unfortunately it takes twice the CPU-capacity
to play VQF than MP3.
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mp3PRO
mp3PRO
is the next generation of MP3. A divison of the Fraunhofer
Institute is working on this together with Thomson
multimedia. mp3PRO is said to offer the same quality of
MP3 at half the file size. This is achieved by a further compression
of a tone’s high frequencies. This SBR (Spectral Band Replication)
is believed to be almost loss-less and represents the PRO
in the name. Sooner or later mp3PRO will take the place of
MP3 as a common standard. Like WMA mp3PRO is backwards compatible,
that means mp3PRO-files can be played with common MP3-players.
These files however sound very dull and rustled. In 2001 the
new format was first presented to the public - now like WMA
equipped with a watermark for copyright-protected files. Whether
mp3PRO is to take the place of the worthwhile proven MP3 -
no one knows; it’s advantages to portable MP3-players are
obvious. Streaming capabilities surely prepare mp3PRO for
the internet as well.
This format is still being developed. A final release is expected
for the end of 2001.
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AAC
- Advanced Audio Coding
After
MP3’s marvelous success especially with the internet-users,
the limits of this new format unveiled quite soon: in lower
bitrates MP3 rapidly lost quality although the file size was
reduced remarkably. This is where AAC comes in. Also developed
by the Fraunhofer Institut the format was meant to
be MP3’s successor. However the aim was not achieved, even
at 96 kbps a heavy loss of quality is noticable. Maybe that’s
why AAC is hardly known anywhere, although it was introduced
in 1999. Above all there are hardly any software-players that
support AAC.
Due to these restrictions AAC was not considered in these
test. Some helpful homepage-links dealing with AAC can be
found in the links-column.
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WAV
One of the first audio-standards; WAVE-files are virtually
of the same quality as data on audio-CDs and therefore offer
the best quality. At the same time these files are very large
(10 MB / min.), that’s why they are unsuitable for everyday
exchange via the internet.
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