TerraTec M3Po, Руководство пользователя

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m3po 47
How come?
"Layer 3" is a clever combination of data compression and data reduction. This means that
digital data is being compressed (The PC calls this
'
packing
'
, for example when converting to
the .ZIP format). In the process, the data will be scanned for repeat data. To save space, this
data will only be saved once and tagged with information, where it needs to re-appear. This
can account for massive reduction in storage space and means that the data will be identical to
the original, once
'
unpacked
'
(i.e. decompressed).
In order to achieve a decrease of 1:11 or more, another process will be required - data reduc-
tion. You may have guessed by its name, that some data will actually be cancelled in this proc-
ess. As the most important aspect is what you are left with, we will take a quick look at the
actual process:
The applied data reduction is based on algorithms, which cancel out inaudible data. For exam-
ple, the brain can hardly hear very quiet sounds, which occur immediately after (a few milli-
seconds) after a loud signal. If the sounds are outside the frequency spectrum of the human
hearing, it becomes literally impossible.
Canceling this data in the recording process leads to another significant reduction in data. This
data has now been permanently erased from the original file. This shouldn’t be too much of a
problem. Reducing data to one eleventh of its original size (128kBit/s) in this manner, does
lead to an audible difference to CD, but the quality should not really be the issue here. .MP3
was never developed in competition to CD, but to offer an alternative option of storing your
audio data. And .MP3 is a great alternative, which is a great benefit to the user.