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Digital audio is usualy compressed (made smaller) in different ways, and to a
different degree. Factors that can be changed (reduced) to achive this compression are
sample rate (number of samples per second taken from the original audio, usualy in Hz);
bit rate (amount of bits or
disk space used to
describe a sample, usualy in kb/sec), and number of chanels (e.g. mono, stereo, 5.1 surround,
etc.). The higher these factors are, the better the quality, the smaller they are,
the less space they take.
We group digital audio formats into two main categoties:
Lossy compression formats, and
Lossless compression formats.
As the names suggest, lossy formats lose some data, and sometimes some quality.
They also take up a lot less
space,
generaly TEN times less then lossless formats with no preceptible loss of quality.
Lossy formats are the choise for listening on the go, sharing, or streaming over the
internet.
Lossless audio formats do not lose any data. They take up much more space on your hard drive,
and are recomended for long term archiving of audio where high fidelity of sound is important.
Probably the most popular digital audio format, and certainly the most famous is
MP3. We will sometimes use MP3 as a kind of benchmark. We will say
"better quality than MP3" (at the same bit rate), or "takes more space than MP3".
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