MP3 - MPEG Layer-3, File Format Information and Conversion
MP3
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MPEG Layer-3
MP3 is a digital audio
compression algorithm that acheives a compression factor of about twelve while
preserving sound quality. It does this by optimising the compression according
to the range of sound that people can actually hear. MP3 is currently (July
1999) the most powerful algorithm in a series of audio encoding standards developed
under the sponsorship of the Moving Picture Experts
Group (MPEG) and formalised by the International Organization for Standardization
(ISO).
MP3 is very different from Layer 2, using an additional MDCT layer to increase
frequency resolution. Its scale factor groups are more optimised for the human
ear, and it uses nonlinear sample quantisation and Huffman coding. MP3 files
(filename extension ".mp3") can be downloaded from many World-Wide
Web sites and can be played using software available for most operating systems
(also downloadable), e.g. Winamp for PC,
MacAmp for Macintosh, and mpeg123 for Unix. MP3 files are usually downloaded
completely before playing but streaming MP3 is also possible. A program called
a "ripper" can be used to copy a selection from a music CD onto your
hard disk and another program called an encoder can convert it to an MP3 file.
Windows ships with limited MP3 encoding support. The output sample rate is
limited to 24khz and the bitrate is limited 56kbps. However, many add-on packages
from open source community make it possible to encode at higher sample rate
and bitrate.
A commonly used open source codec is LAME.
LAME comes in different forms, including a ACM (Audio compression manager) codec
and a DLL (lame_enc.dll). Caution: LAME ACM does not work well on many computers,
regardless which software is loading it. It is best to avoid installing LAME
ACM and use lame_enc.dll instead.
MPEG.ORG is an excellent source for additional
information on MPEG format and usage.
www.mpeg.org
Convert from
MP3(MPEG Layer-3)
To extract audio from MP3(MPEG Layer-3), you will need Audio Converter.
Please see the following tutorials.
Convert to
MP3(MPEG Layer-3)
To convert to MP3(MPEG Layer-3), you will need Audio Converter. Please see the following tutorials.
