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Alcorn McBride MP3 Audio Machine User’s Manual • Rev H • April 2, 2004
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Encoding
Making MP3 files involves using an encoder, and you can find them readily available
from the web. A couple that we have seen work well are
Audio Catalyst,
which is
available from
Xing Technology Corporation
(www.xintech.com), and
Music
Match JukeBox
available from
MusicMatch
(www.musicmatch.com)
.
Fraunhofer
IIS Institute in partnership with Thomson Multimedia own patents on tools that make
MP3-compliant bitstreams. Due to the fact that Fraunhofer charges a royalty from
each encoder distributor, it is difficult to find a freeware MP3 encoder. But at the
time of this printing, MusicMatch (mentioned above) does have a free encoding
utility in their Jukebox. Audio Catalyst is a lot more flexible than MusicMatch
Jukebox, but you’ll need to purchase it.
Quality
The 16-bit linear PCM format, like a WAV file, can provide higher quality audio
playback than the MPEG format, but at the same time it consumes about ten times as
much storage space per minute. This is based on a 128Kbps sample rate.
You CAN
get better than CD quality audio in an MP3 file
– you just have to encode it at a
higher bitrate, like 160Kbps. You also have to make sure your source material is not
from a CD, because then you could never get any better quality than CD anyway.
Below is a useful comparison of bitrates, quality, and file size. All you will need to
do is choose the bitrate at which you want the file encoded, which best fits in with
your storage space requirements. The most common, and recommended bitrates are
bolded.
Bitrate
(Kbps)
Quality
File Size
Original
WAV
Best quality achievable is whatever the source is.
10.47Mbytes
80
FM radio quality.
.594Mbytes
96
Near CD quality
.712Mbytes
128
Close enough to CD Quality most listeners can’t tell a difference 0.950Mbytes
160
Better than CD quality (at 48KHz) – good for high end stereos
1.19Mbytes
320
Best quality, good for archiving, but takes up lots of memory
2.38Mbytes
