“The audio compression standard Mp3 (MPEG 1 Layer 3) has become
very popular recently. Mp3 is a “lossy” compression, that tries to
reduce the audio data to the information which is actually heard by
a human. The Mp3 encoder uses a psychoacoustic model to decide
whether information is relevant or not. A strong signal, for
example, will “mask” some of the following (weaker) signals.
Because of this, it is complicated to technically measure the
quality of Mp3 compressed music. The only way to “measure” the
quality of an Mp3 encoder is to use human testers, which tend to be
very subjective. So much on the theory, now lets have a look on
what you need to encode/play Mp3’s on your Linux box.”
“In case you want to convert your old audio CDs into Mp3, you
will need a CD-ripper. A CD-ripper gets the digital data from the
CD without loss. If you would use a standard wave recorder, the
data on the CD would be converted into a analog signal and back
into a digital signal by your sound card, before it would reach the
recorder. This causes quality loss, but if your cdrom doesn’t
support ripping, it is your only choice. One of the most used
CD-ripper is probably CDParanoia , it exports the audio data as
wave or aiff file which can be used by an encoder.”
“The next thing you need is a Mp3 encoder to compress your sound
files. There are several Mp3 encoders for Linux, most of them
are based on the dist10 ISO demonstration code. One of those
encoders is Bladeenc. It’s quality is limited by the ISO
psychoacoustic model and it doesn’t support variable bit rates.
Variable bit rate means that the encoder can adjust the bit rate to
the complexity of the signal. There’s another program named LAME,
which stands for LAME Ain’t an Mp3 Encoder. As the name indicates
LAME is not an Mp3 encoder, but a GPLed Patch against the dist10
code. This way LAME doesn’t violate any Copyrights of the FhG.”