HDCD Rips and NDX

One other thing–tracks ripped on a Naim server from HDCD-compatible discs will, if played back through an HDCD-compatible DAC, trigger HDCD decoding just as if played from a Compact Disc in real-time.

Dave - intereting - I am using dBPoweramp as the ripper and so haven't noticed that. Out of interedt what do the Naim rips look like when rupping HDCD, I  guess they are not creating 24 bit wav files?

Simon

A shame though that the Naim DAC isn't HDCD compatible. Is the one in the NDX?

Regarding HDCD, the UnitiServe and HDX will create a "bit-perfect" copy of any HDCD encoded disk inserted into it.

However, in order to enjoy the full capabilities of an HDCD encoded disc, the player must have a HDCD decoder/digital filter (e.g. Pacific Microsonics PMD-200) which is activated when playing encoded discs.

So, if you've got a DAC that can decode HDCD streams, you're in business!

Regards,
Michel

Keith - good question, I am hoping Dave can expand a little on his earlier post. However with dBpoweramp you can enable the HDCD plugin in the DSP settings, and this converts the 20bit HDCD data into a regular 24bit wave file (I assume by truncating the 4 least significant bits). This wav file can then be played back by any DAC that can handle 24bit PCM - and as per my OP - it sounds fantastic on the NDX DAC.

Simon

I'm a bit confused. On this thread: https://forums.naimaudio.com/di...ent/1566878604243397 I asked Phil Harris of naim whether an HDX would rip the full 20 bits of an HDCD, and Phil replied 'The HDX does not have an HDCD decoder, so no'. So does the HDX rip the 'extra' 4 bits or not, or is it that it just doesn't play them back?

There are no "extra" 4 bits–the HDCD process, if you recall, affects the filter coefficients and replay gain (to simplify matters) while utilizing the LSB to toggle the appropriate decoding.

As Naim Audio is an HDCD licensee (CD555 / CDS3 / CDX2 / CD5 XS), discussion of dBpoweramp's unlicensed hdcd.exe library for use as a playback alternative to Naim's own licensed HDCD products may be restricted–we'll leave this to the moderators to decide.

Bit-perfect ripping is one thing–post-processing using the in-band decoding flags (covered under the HDCD patent) is another.

Dave, I am not aware that Illustrate use unlicenced codecs - I think best leave assetions like that to another forum and not here.

However, my question to you remains unanswered?  So I have researched HDCD and discovered it uses inband signalling of the 16 bit PCM and the PCM is modified ti make it look like 20bits, at the expense of a tiny increase in noise.

Therefore any ripper by default will pass the HDCD in band signalling in the 16bit wav file. The software I use interpretes that signalling to create a 24 bit file. It may or may not use the same algorithms that Pacific Microsonics use... but I see Micorsoft windows machines using Windows Media Player 9 or higher can decode HDCD (Microsoft own the IPR) , so it might be that library that Illustrate are using on the Windows platform.

However as Phil from Naim has said the Naim Dacs don't support HDCD, I guess one would near a processor in front of a Naim DAC to allow the HDCD signal to be expanded into a 24 bit PCM signal.

Thanks

Simon

I'm still a bit confused - perhaps Phil Harris could clarify why he said 'no' when I asked him whether an HDX ripped the full HDCD information.

I can't find any mention of HDCD in the spec for the NDX or DAC either.

>"discussion of dBpoweramp's unlicensed hdcd.exe library for use as a playback"

HDCD is owned by Microsoft, who hold the relevant HDCD Patents. Microsoft have indicated that any software running on Windows does not need a Patent license from Microsoft for HDCD decoding, so this is our basis for a HDCD decoder. 

In order to listen to a HDCD at its full resolution via HDX or NDX you need two things:

First you need a bit perfect copy of the original HDCD (remember that a HDCD is 16bit plus a HDCD info "hidden" inside the 16bit data).

Second you need a software HDCD decoder that converts the 16bit WAV file to a 24bit WAV file, but it is not a true 24bit WAV file. It is "only" a 20bit WAV file.

In case you only make a bit perfect rip without using a HDCD encoder after the rip you get a 16bit WAV file.

And by the way: Creating a HDCD copy on a CD-R is a nice way to check whether your copies are bit perfect, since when the HDCD light with your HDCD capable CD player lights up you can be sure to have created a bit perfect WAV file and this is no rocket science at all although some people here want you to think so And I compared HDX made rips with dBpoweramp rips (of course using the "right" settings" and on my 100% Naim system there is no difference at all and believe me I would have liked my HDX made rips to sound better since I paid quite a lot for the HDX!

I do not think it matters, in that if an end user decides to run on Wine, Microsoft the Patent holder is never going to go after that individual (Patents tend to be governed around commercial interests, there is zero commercial interest in an end user doing something for their own use). This is of course different than if we created a dBpoweramp which ran on Linux natively.