Sony has made a large effort to make unavailable computer emulation
of atrac. If you want to test a few specific files I would be happy
to convert a wave file to atrac and back to PC wave and send it back
to you to look at. I would make the transfer from wave to atrac all
digital but I only have an ablility to make the atrac back to wave
via line level analog. It would still be pretty clean but you may
want to use someone with a digital out on their Minidisc. The limit
on email to me for the conversion is 5 megs per message. please note
that the first 3 secs may be cut on a digital record. If you want
address it to richpeet(at)attbi.com and note at=@.
--- In Gianni Pavan <> wrote:
> I think the effect of compression on sound quality it is still a
debatable
> question. It is very important to know which sound features may be
affected
> by compression and how the acoustic context may affect the
compression
> algorithm's behaviour. I made some tests with MP3 encoding/decoding
and
> several effects can be easily detected by hearing or by
spectrographic
> analysis. Of course, with MP3 the compression is scalable and
alterations
> increase with increasing the compression factor (which corresponds
to
> reducing the bit rate).
> The MP3 works both in frequency and in time; by using algorithms
based on
> both frequency and time masking, it can cut a short segment of a
signal if
> it is just after a strong sound. This happens with sperm whale
clicks: if
> they are very loud, after each click the spectrogram shows a short
segment
> of silence (it is not noticeable by hearing, but it may cut some
important
> features we measure in the 10 ms after a click!).
>
> I don't know how ATRAC behaves. As I can't afford the buy of an MD
recorder
> only for this testing, I would like to know if there is some
software able
> to perform ATRAC coding/decoding I could use for doing some tests.
>
> Any information will be appreciated,
> regards,
> Gianni
> --------------------------------------------------------------
> Gianni Pavan
> Email
> Centro Interdisciplinare di Bioacustica e Ricerche Ambientali
> Universita' degli Studi di Pavia
> Via Taramelli 24, 27100 PAVIA, ITALIA
> Tel/Fax +39-0382-525234 Laboratori
> Tel/Fax +39-0382-526208 Segreteria
> Web http://www.unipv.it/cibra
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