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发表于 2022-3-13 18:32:09
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MP3 versions were judged favourably in both of the tests in which they appeared, with the mean
values being 4.95 and 4.68 for Tests A and C, respectively. Surprisingly, the MP3 versions also outscore
the CD versions(and by a clear margin for Test A), as both were created using an identicalsource file.
Data would appear to suggest that this unexpected result may be attributed to Test A only. If taken
on face value, then our result indicates that the process used to encode the song‘Charm Offensive‘
to a 192kHz MP3, yielded a better (if not equivalent) result than the dithered version down-converted
to 16 bit/44.1kHz (for CD). Thisresult wasseen assomething of an anomalyand therefore, the CD and
MP3 files were checked again to ensure that levels were matched, which they were to within 0.01
LUFS. Further frequency analysisshowed the MP3 version exhibiting a greater reduction in higher frequencies and much more abrupt filtering after the Nyquist frequency. Although there are differences
between the files, one would not expect the loss of high frequency information to contribute to the
perception of improved audio quality. |
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发表于 2022-3-13 11:23:00
发表于 2022-3-13 14:24:38
