20 Now that I know how to assess quality, come on, tell me the results of these tests. (MPEG-Audio)
Description
This article is from the MPEG FAQ, by Frank Gadegast phade@cs.tu-berlin.de with numerous contributions by others.
20 Now that I know how to assess quality, come on, tell me the results of these tests. (MPEG-Audio)
Well, for details you should study one of those AES papers
listed below. One main result is that for low bitrates (60
or 64 kbps per channel, i.e. a compression ratio of around
12:1), Layer-2 scored between 2.1 and 2.6, whereas Layer-3
scored between 3.6 and 3.8.
This is a significant increase in sound quality, indeed!
Furthermore, the selection process for critical sound material
showed that it was rather difficult to find worst-case
material for Layer-3 whereas it was not so hard to find
such items for Layer-2.
For medium and high bitrates (120 kbps or more per channel),
Layer-2 and Layer-3 scored rather similar, i.e. even
trained listeners found it difficult to detect differences
between original and reconstructed signal.
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