AAC (.aac) - "Advanced Audio Coding", next
generation audio codec developed by Fraunhofer that seeks to
preserve audio quality at lower bitrates. High licensing
costs have kept this audio codec from the mainstream
AIFF (.aiff) - default sound file on Macintosh
computers
ADPCM - Compressed WAV format. ADPCM (Adaptive
Differential Pulse Code Modulation) is an audio compression
scheme which compresses from 16-bit to 4-bit for a 4:1
compression ratio.
ALAW - Compressed WAV format. A-Law (or CCITT
standard G.711) is an audio compression scheme common in
telephony applications. It is a slight variation of the
u-Law compression format, and is found in European systems.
This encoding format compresses original 16-bit audio down
to 8 bits (for a 2:1 compression ratio) with a dynamic range
of about 13-bits. Thus, a-law encoded waveforms have a
higher s/n ratio than 8-bit PCM, but at the price of a bit
more distortion than the original 16-bit audio. The quality
is higher than you would get with 4-bit ADPCM formats.
Encoding and decoding is rather fast and generally, widely
supported.
ALF2CD - Compressed WAV format. ACM codec
developed by the NCT Company. Good for keeping of CD-quality
music.
audiophile - one with extreme interest in high
quality sound
bitrates - speed at which audio data travels per
second
BURN-Proof - short for "Buffer Underrun Proof",
this technology was developed by Sanyo to combat the most
common problem in burning CDs. If a data stream is
interrupted while burning, the cd creation process is often
ruined. BURN-Proof combats this by connecting the data
seamlessly between the recorded point and the recording
start point
burning - term for writing data to a cd
codec - short for "compression/decompression",
basically an algorithm or system of rules to transform a
file.
.cda - not a file format but a way of displaying
audio tracks, much like a menu
CDDB - "Compact Disc Database", online lookup
tool for retrieving album, artist, and track information,
especially helpful for completing MP3 ID3 tags
cd-r - short for "cd-recordable", this media type
allows you to record audio or data files and does not allow
erasing. Recording audio files allows for compatibility with
car and home stereo systems.
cd-rw - short for "cd rewriteable". These discs
can record and erase audio and data up to 1,000 times.
However, most car and home stereos do not support this media
type yet.
cd text - disc and track info embedded on an
audio CD
CCIT U-Law - Compressed WAV format.
constant bit rate (CBR) - bit rate remains the
same throughout the audio file. Compare with variable bit
rate (VBR)
converter - software program that transforms one
file format to another
decoding - making a format readable. MP3 players
"decode" MP3 by being able to play the data format as audio.
However, the term usually refers to the process of
converting MP3 to WAV
disc-at-once (DAO) - single session burning
process that cannot be interrupted and does not allow any
data to be added once burned on a disc. Does not add 2
second gaps between tracks as does track-at-once recording
encoding - the process of converting any audio
format to MP3
GSM - Compressed WAV format. Good for keeping of
human speech.
G.726 - Used for computer telephony. Good for
keeping of human speech.
ID3 - small file that can be attached to an MP3
that contains album, artist, track, and other info.
jitter correction - jitter occurs with digital
audio extraction (ripping)or when digital audio is converted
to analog. This correction feature helps restore the audio
to its original condition
kbps - "kilobytes per second", a measurement that
is used to judge the size of an audio file. Uncompressed
audio such as WAV format is 1411 kbps, MP3 compresses this
size to about 1/10 on average (varies depending on user
settings when encoding)
MP3 (.mp3) - MPEG Layer III, digital audio
compression format achieving smaller file sizes by
eliminating sounds the human ear can't hear or doesn't
easily pick up.
mp3pro - audio codec developed by Thomson
Multimedia that attempts to achieve the same audio quality
in smaller file sizes than MP3
normalizing - the process of making audio files
the same volume
OGG Vorbis - open source audio codec designed to
compete with MP3. Since it is not licensed like MP3,
software using this codec does not have to pay royalties.
psychoacoustics - study of what sounds the human
ear can detect. MP3 exploits the limits of human
psychoacoustics to get smaller file size with limited
detectable quality loss.
PCM - Standard Windows WAV format for
noncompressed audio files. Pulse Code Modulation (PCM) is
the standard method of digitally encoding audio. It is the
basic uncompressed data format used in file types such as
Windows .wav.
RA (.ra) - "Real Audio" file type from Real
Networks. Usually produced by any of Real Networks'
proprietary software.
RAW - Raw format of audio files. Doesn't contain
header of an audio file.
ripping - also called digital audio extraction,
this is the process of taking CD audio and recording it to a
computer in any file format. When the transfer is from CD to
MP3, the process is both ripping and encoding.
RM (.rm) - "Real Media", fie type from Real
Networks.
track-at-once (TAO) - this burning process can
write tracks individually, up to 99 total. Automatically
places 2 second gaps between tracks.
ULAW - Compressed WAV format. u-Law (or CCITT
standard G.711) is an audio compression scheme and
international standard in telephony applications. u-Law is
very similar to A-Law, a variation of u-Law found in
European systems. This encoding format compresses original
16-bit audio down to 8 bits (for a 2:1 compression ratio)
with a dynamic range of about 13-bits. Thus, u-Law encoded
waveforms have a higher s/n ratio than 8-bit PCM, but at the
price of a bit more distortion than the original 16-bit
audio. The quality is higher than you would get with 4-bit
ADPCM formats. Encoding and decoding is rather fast and
generally, widely supported.
VOX - Dialogic ADPCM format. The Dialogic ADPCM
format is commonly found in telephony applications, and has
been optimized for low sample rate voice. It will only save
mono 16-bit audio, and like other ADPCM formats, it
compresses to 4-bits/sample (for a 4:1 ratio). This format
has no header, so any file format with the extension .VOX
will be assumed to be in this format.
variable bit rate (VBR) - encoding process where
the codec makes the choice for how many bits are used on
each segment of music. More complex segments get more bits.
VBR was created with the goal of efficient use of file
sizes.
WAV (.wav) - uncompressed audio format developed
by IBM and Microsoft. Became standard audio file used on
PCs.
WMA (.wma) - "Windows Media Audio", Microsofts
proprietary audio codec designed to compete with MP3. Claims
competitive sound quality at lower bitrates