@Archimago
I did no indeep reading leave alone understanding of that patent so i
may be wrong.
A blind quote that may not describe how the realworld implementation
" The listener with access to all 24 bits may use the decoder of figure
5B to enjoy full bandwidth lossless reproduction of the 13-bit signal at
point "A", i.e. with a resolution of 17 or 18 bits in the critical
frequency range 0-7 kHz as a result of the 96kHz shaper."
Thanks to esldude finding this :)
http://patentscope.wipo.int/search/en/detail.jsf?docId=WO2013186561&recNum=132&maxRec=599628&office=&prevFilter=&sortOption=&queryString=nano+OR+filter+OR+ceramic&tab=PCTDescription
Thanks for the link. I believe I linked to that patent but didn't click
on the adjacent tab to see the detailed description!
Interesting. Indeed, this implementation described looks like it only
leaves the 13 MSB's untouched, and the 14-16th bits "lossy" in some
form. Also, it looks like the intent is:
-"Thus, it is generally not possible to pack losslessly and with PCM
compatibility a 16-bit 96kHz signal into a 16-bit 48kHz channel, and
neither is it generally possible to pack losslessly and with PCM
compatibility a 24-bit 96kHz signal into a 24-bit 48kHz channel.
However, PCM-compatible lossless packing of a 16-bit 96kHz signal into a
24-bit 48kHz channel is usually feasible."-
and this:
-"The coefficients for Gerzon's 96kHz shaper, which provides nearly five
bits of perceptual improvement, were given in Acoustic Renaissance for
Audio, "A Proposal for High-Quality Application of High-Density CD
Carriers" private publication (1995 April); reprinted in Stereophile
(1995 Aug.); in Japanese in J. Japan Audio Soc, vol. 35 (1995 Oct.);
available for download at www. meridian- audio.com/ara. Stuart provides
a careful analysis considering the capabilities of human hearing
("Coding for High-Resolution Audio Systems" J. Audio Eng. Soc, Vol. 52,
No. 3, 2004 March, see especially figure 16) from which one may conclude
that a 44.1 kHz sampled digital system properly quantised with TPDF
dither (but without noise shaping) to 20.5 bits will always provide
sufficient dynamic range as a distribution medium. The non-noise-shaped
noise spectral density is reduced by a further 3.4dB when 96kHz sampling
is used. We can conclude that a 16-bit 96kHz channel with appropriate
noise shaping is entirely adequate as a distribution format, meeting
audiophile requirements with some margin to spare"-
Interesting, Meridian is indeed feeling that dithered & noise-shaped
16/96 is good enough for "audiophile requirements". The technique is
more complicated than I envisioned. The technique can compress 16/96
into 24/48 "usually feasibly" in a "lossless" fashion in about 97% of
those songs analyzed because it just so happens that there's not too
much happening in the upper frequencies in most songs (no surprise!).
Presumably then, if a piece of music had a lot of "detail" above 48kHz,
then this system would not be able to capture it all... Hmmm, this is
certainly a different type of definition of "lossless" than what we're
used to isn't it? Some kind of "limited" losslessness depending on how
close the music conforms to expectations.
It'll be good to see how this all works out!
Archimago's Musings: (archimago.blogspot.com) A 'more objective'
audiophile blog.
------------------------------------------------------------------------
Archimago's Profile: http://forums.slimdevices.com/member.php?userid=2207
View this thread: http://forums.slimdevices.com/showthread.php?t=102934