Image Processing Reference
K-1 A Variety of Audio Formats (Continued)
MPEG-1 audio—layer 1
A simplified variant of MUSICAM.
MPEG-1 audio—layer 2
This is identical to the MUSICAM standard.
Also known as MP3, it is based on the ASPEC
Masking pattern adapted Universal Sub-Band Integrated
Coding and Multiplexing. This is designed to be used in
Digital Audio Broadcasting (DAB Radio).
This is considered to be a legacy codec, which was quite
complicated to operate. A newer version is available in
QuickTime but this will likely be superseded as the AAC
codec increases in popularity. The version 2 codec is about
the same as MP3 in terms of quality but stores the
information in a more compact form, resulting in smaller file
sizes. MP3 beats it on popularity but in terms of quality
versus size it is somewhere between MP3 and AAC.
A telephony codec that is good for speech but not much else.
It is useful for extracting voice from recordings with other
ambient noise since it ignores everything but speech. This
codec is not great at high signal levels so you may want to
adjust levels before encoding. Compression ratio is very good
when it is used for speech-only audio tracks.
A family of codecs for different applications from low-quality
voice to high-quality stereo music and surround sound.
Surround sound 5.1 format. Also being proposed for
delivering satellite radio to moving vehicles.
Windows Media Audio
These are otherwise known as WMA. There are several
alternative codecs but they are not all available on every
platform. Naturally, they are all well supported on Windows.