I'll bet it is able to decode but doesn't infringe patents'. Tbh lots of players have included decoding (burr brown added it to some dac's and iirc oppo players do it as well. However I do wonder if they are just converting to a reasonable 20bit or actually doing it properly.
Probably found a away to do it basically to not infringe patent. MS never wanted it for audio I'll bet till Pacific came along everyone said you couldn't reliably use LSB. I'll bet MS use it's patents in data compression of some sort. Iirc in the original spec there were all sorts of funnies I'll bet aren't in the decode it wasn't just a straight hold 20bit on a 16bit format. It raised volume of very quite input signals so allows more bits to describe the recording then embeds the info in the LSB on reducing volume again. There were also a choice by encoder of 7 different filters that could be chosen to better represent/work with the program material at that point of process. And codes are embedded to tell pmd filter which was used at which point in music so it can reconstruct properly. I'll bet the reconstruction filter stuff insnt replicated in software as well it needs done in filter... It's actually a very clever system much more complex and capable than people realise (it wasn't just a expansion of dynamic range). A small extract about how filter thing works follows and link to site with most interesting and accurate write up on how it works. They knew their stuff as created a damn good filter for redbook cd as well > The HDCD documents also aim at tackling what the creators see as > another limitation of Audio CD. The choice of conventional LPCM with a > 44,100 sample/sec rate places an upper limit of 22.05 kHz on the range > of frequencies that can be recorded without risking problems. > Conventionally, engineers employ time-symmetric filtering to avoid > problems due to the input being recorded having components above 22.05 > kHz. However this has lead to worries, partly about pre-ringing > effects, and partly due to the loss of high frequencies that may have an > audible effect. > > HDCD claims to tackle this by using a choice of filters when recording. > As with the peak limiting and low level gain adjustments, the aim is > that an HDCD player can then process the values on the disc and be told > via the hidden control codes - which of a menu of replay filters to > use for each section of music. So, for example, sustained notes and > chords can be replayed using a filter similar to the classic > time-symmetric (sinc-like) form. But transient spikes can be replayed > using a filter that causes the output to contain some frequencies above > 22.05 kHz, so trying to mimic reproducing a wider bandwidth. > ------------------------------------------------------------------------ mr-mac's Profile: http://forums.slimdevices.com/member.php?userid=65394 View this thread: http://forums.slimdevices.com/showthread.php?t=105158
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