1. AUDIO FILE FORMAT
Kalpita Potawad
M.L.I.SC
2012-2013

2. CONTENT
 Definition
 History
 Types
 Audio file formats extensions
 Advantages and Disadvantages of audio file
format
 Three categories
 Examples

3. DEFINITION
An audio file format is a file format for
storing digital audio data on a computer
system. This data can be stored
uncompressed, or compressed to reduce
the file size. It can be a raw bitstream, but
it is usually a container format or an audio
data format with defined storage layer.

4. HISTORY
Phonograph
In the early 19th century, it was all
but impossible to imagine what
great changes were in store for the
world of audio. Although the first
successful recording device was
developed in 1855, it wasn't until
Thomas Edison's phonograph
(invented in 1877) and Emile
Berliner's Gramophone (patented in
1887) that the phonograph started
to come into its own.

5. RADIO
It's hard to imagine a world without radio,
but the technology has only been around
since the 1920s.The theoretical basis of
the propagation of electromagnetic waves
was first described in 1873 by James
Clerk Maxwell in his paper to the Royal
Society A dynamical theory of the
electromagnetic field, which followed his
work between 1861 and 1865.

6. 8-TRACK
Invented in the early 1960s by William
Powell Lear, and heavily marketed and used
in the '70s, the 8-track was the premier
portable audio format for almost 15 years.
The 8-track was designed around a single reel
with the two ends of the plastic recording
tape joined with a piece of conductive foil
tape to make one continuous loop.

7. CASSETTE TAPE
The cassette as we know it didn't come into
the average home until the late 1970s.
However, magnetic tape recording got its
start in music studios around 1950.
Musicians could record in longer sessions,
and seamless splice editing allowed artists
and producers to select and combine the
best cuts into polished songs. The allure of
magnetic tape as a recording medium
blossomed.

8. COMPACT DISC
A compact disc (or CD) is an optical disc used for
storing digital data. It was originally invented for
digital audio and is also used as a data storage
device, a CD-ROM. CD-ROM reading devices are
frequently included as a component in personal
computers. In general, audio CDs are distinct
from CD-ROMs, and CD players intended for
listening to audio cannot make sense of the data
on a CD-ROM, though personal computers can
generally play audio CDs.

9. DIGITAL AUDIO TAPES (DAT)
Introduced in 1987 for the studio market, digital audio
tapes quickly became de rigueur in professional
recording industry circles. Although DATs never fully
caught on in the consumer market because of the
high cost of DAT players, they remain a mainstay of
the pro-audio world because of their low price and
enhanced digital storage capabilities. Another factor
helped keep DATs from catching on with consumers:
A tax was added to each tape sold, earmarked to
compensate music companies for songs that could
be pirated. Most DAT users today use computer-
grade DAT tape to circumvent the tax.

10. MINIDISC
MiniDisc (MD) is a disc-based data
storage device for storing any kind of
data, usually audio. The technology
was announced by Sony in 1991 and
introduced January 12, 1992. MD
Data, a version for storing computer
data was announced by Sony in 1993,
but it never gained significant ground,
so today MDs are used primarily for
audio storage. The audio discs can be
premastered or recordable (blank).

11. MP3
Invented in 1989 in Erlangen, Germany, MP3
has quickly come to symbolize a paradigm
shift in the way many people access their
music. The home computer revolution, along
with the Internet, has allowed millions of Net-
connected music fans to take advantage of the
latest audio medium.
AAC
AAC is a new audio compression technology, Advanced
Audio Coding. This new standard, developed by Dolby, the
Fraunhofer Institute, and others, may become the major
ingredient in 21st century digital music distribution. The
AAC codec was formally introduced to the world at the
Consumer Electronics Show 2001, along with dozens of
new digital audio players able to play AAC files.

12. TYPES
 There are three major groups of audio file formats:
 Uncompressed audio formats, such as WAV, AIFF, AU or raw
header-less PCM;
 Formats with lossless compression, such as FLAC, Monkey's
Audio (filename extension APE), WavPack (filename extension
WV), TTA, ATRAC Advanced Lossless, Apple Lossless
(filename extension m4a), MPEG-4 SLS, MPEG-4 ALS,
MPEG-4 DST, Windows Media Audio Lossless (WMA
Lossless), and Shorten (SHN).
 Formats with lossy compression, such as MP3, Vorbis,
Musepack, AAC, ATRAC and Windows Media Audio Lossy
(WMA lossy)).

13. AUDIO FILE FORMATS EXTENSION
.mid MIDI (Musicl Instrument Digital Interface)
.wav Waveform Extension
.aif Audio Interchange Format
Motion Picture Expert Group Audio -
.mp2
also referred to as MPEG-1 layer-2 or
.mp3
MPEG-1 Layer-3
.ra
.ram Real Audio
.rpm

14. ADVANTAGE AND DISADVANTAGE OF AUDIO FILE
FORMATS
The following is a list of the more
common audio file formats along
with the advantages and
disadvantages of each for Web
design.

15. .MID
Wide support in many browsers with no need for a plugin.
They can have very good sound quality, but this can vary
somewhat with the quality of the sound card.
Very small file size for a lengthy selection.
The files are instrumental only.
The files can not be recorded. They must be synthesized on
a computer with special hardware and software.

16. .WAV
Very good sound quality.
Widely supported in many browsers with no need for a
plugin.
You can record your own .wav files from a CD, tape,
microphone, etc.
The very large file sizes severely limit the length of the
sound clips that you can use on your Web pages.

17. .AIF
Very good sound quality.
Widely supported in many browsers with no need for
a plugin.
You can record your own .aif files from a CD, tape,
microphone, etc.
The very large file sizes severely limit the length of
the sound clips that you can use on your Web pages.

18. .MP2/.MP3
This is a compressed format which makes the sound files
substantially smaller.
The sound quality is very good. If an MP3 file is recorded and
compressed properly, the quality can rival that of an actual CD.
New technology is emerging that will allow you to "stream"
the file so that the audience doesn't have to wait for the entire
file to download before they can hear it.
The file size is still larger than a Real Audio file and a whole
song would still take quite awhile to download over a
normal phone line connection.
Your audience must download and install a helper
application or plugin to hear the sounds.

19. .RA/.RAM/.RPM
Very high degree of compression with smaller file sizes than .mp2
or .mp3. Whole songs files are reasonable to download.
The files can be "streamed" from a normal Web server without any
special software so that the audience can begin listening to the
sound before the file has completely downloaded. Whole songs
will start paying within seconds over normal phone line
connections.
The sound quality is poorer than the quality of the .mp2 or .mp3
files, but the new G2 player and encoder have increased the
quality considerably.
Your audience must download and install a helper application or
plugin in order to appreciate the excellent quality of the new G2
standard. However, browser manufacturers are beginning to
include a plug-in for the older version 5 player with the browser
downloads.

20. THREE CATEGORIES
 Uncompressed audio formats A WAV audio file is
an example of an uncompressed audio file.
 Lossless compression The WMA audio file format
uses lossless compression.
 Lossy compression MP3 and Real Audio files
use a lossy compression.

21. EXAMPLE
 Example 1:
 audio-info (content): A song called "Hung Up" by
"Madonna"
 File-format (format): 4.5MB MP3 file encoded at
192Kbps bitrate.
 Example 2:
 audio-info (content): A music video called "Hung
Up" by "Madonna"
 file-format (format): 35MB AVI file, MP3 audio
codec encoded at 192Kbps, DiVX video codec
encoded at 600Kbps