24 bits 96 kHz CD question

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ianm0
Posts: 6
Joined: Mon Nov 21, 2011 9:10 pm

24 bits 96 kHz CD question

Post by ianm0 » Sat Nov 26, 2011 5:24 am

I have a CD of 24 bits + 96 kHz. When I play it, my Cambridge Audio Dacmagic DAC shows it's 44.1 kHz. So I view the files on my PC, the Audio Properties page indicates the CD is of 16 bits, 44.1 kHz. I do that twice using different CD's players as transports & get the same result. I then rip a track using MediaMonkey and view the ripped file. Again it shows 16 bits, 44,1 kHz.

I then subject Reference Recordings' "30th Anniversary Sampler" (a 24 bits CD, but sampling rate not known to me) through the same process, it is shown as a 16-bits, 44.1 kHz CD.

Could it be that once a CD is detected, the default CD red book metadata of 16-bits & 44.1 kHz are displayed irrespective of the actual number of bits and sampling rate?

Out of curiosity, I do one more thing on my PC, which has a Realtek onboard sound card. I set the default digital output to 24 bits and 96 kHz and route the digital signal from my PC via coaxial SPDIF to my Cambridge Audio Dacmagic DAC , the latter displays the correct 96 kHz. (Edit: forgot to mention that if default digital output is set to 16 bits & 44.1 kHz, DAC will show 44.1 kHz)

Can anyone explain what is going on with 24 bits, 96 kHz (or higher sampling rate) CD's? In particular,

1. Are the CD players used as transports (in para 1) outputting 44.1 khz data to the DAC?
2. Refer to preceding paragraph, is the DVD in my PC retrieving the actual 96 kHz data from the CD, or my PC has upsampled 44.1 kHz data to 96 kHz (due the default output setting of 24 bits, 96 kHz)?

Mystery thickens and needs clarification from my learned friends.

Eyal
Posts: 3110
Joined: Sun Jun 26, 2005 9:27 am
Location: Québec

Re: 24 bits 96 kHz CD question

Post by Eyal » Sat Nov 26, 2011 8:03 pm

Standard Audio CD is 16-bit/44.1 kHz. What you have is an HDCD which is coded at 24-bit/44.1 KHz.
Most CD readers can read this 24-bit format, but most software just ignore it thus strip the additional 8 bits of data.

From what I recall, the only way to directly extract to 24-bit is by using specialized software like HDCD.EXE, dbpoweramp or Foobar w/specific plugin.

Some refs.:
http://en.wikipedia.org/wiki/High_Defin ... le_Digital
http://forum.doom9.org/showthread.php?t=129136
http://lukeskaff.com/?tag=hdcd
http://forum.dbpoweramp.com/showthread. ... -to-24-Bit

Eyal :~)
Skins for MediaMonkey: Cafe, Carbon, Helium, Spotify, Zekton. [ Wiki Zone ].

ianm0
Posts: 6
Joined: Mon Nov 21, 2011 9:10 pm

Re: 24 bits 96 kHz CD question

Post by ianm0 » Sat Nov 26, 2011 11:26 pm

[quote="Eyal"]Standard Audio CD is 16-bit/44.1 kHz. What you have is an HDCD which is coded at 24-bit/44.1 KHz.
Most CD readers can read this 24-bit format, but most software just ignore it thus strip the additional 8 bits of data.

But if I have a 24-bit/96khz HDCD, I could understand that 8 bits of data are stripped, but why the sampling rate is changed to 44.1 kHz?

1. If so, any way to avoid this?
2. I am using Win 7, a 24-bit/96khz track is shown as 16-bit/44.1khz via Explorer. Is there any software which will display the metadata of a 24-bit/96khz track correctly?

mcow
Posts: 820
Joined: Sun Sep 21, 2008 9:35 pm
Location: Cupertino, California

Re: 24 bits 96 kHz CD question

Post by mcow » Sat Feb 18, 2012 2:18 pm

Eyal wrote:Standard Audio CD is 16-bit/44.1 kHz. What you have is an HDCD which is coded at 24-bit/44.1 KHz.
Most CD readers can read this 24-bit format, but most software just ignore it thus strip the additional 8 bits of data.
That's not correct.
HDCD data is 16/44.1. It uses the lowest-resolution bit of each sample (which on regular CDs is dithered—essentially random) to encode extra modal information which allows it to get an extra four bits of virtual info, and also to shape the oversampled signal. In effect, you get 20/176. A DAC without HDCD yields a signal that is less detailed and slighty compressed: the loud parts are slightly quiet, the quiet parts are slightly loud, compared to HDCD playback.

I don't know what kind of CD ianm0 has. As far as I know, 24/96 discs are SACD or DVD Audio. Many SACDs were printed with a redbook (16/44.1) image on the flip side.

Ternaugh
Posts: 13
Joined: Fri Aug 10, 2007 4:05 am

Re: 24 bits 96 kHz CD question

Post by Ternaugh » Thu Feb 23, 2012 3:20 am

mcow wrote:
Eyal wrote:Standard Audio CD is 16-bit/44.1 kHz. What you have is an HDCD which is coded at 24-bit/44.1 KHz.
Most CD readers can read this 24-bit format, but most software just ignore it thus strip the additional 8 bits of data.
That's not correct.
HDCD data is 16/44.1. It uses the lowest-resolution bit of each sample (which on regular CDs is dithered—essentially random) to encode extra modal information which allows it to get an extra four bits of virtual info, and also to shape the oversampled signal. In effect, you get 20/176. A DAC without HDCD yields a signal that is less detailed and slighty compressed: the loud parts are slightly quiet, the quiet parts are slightly loud, compared to HDCD playback.

I don't know what kind of CD ianm0 has. As far as I know, 24/96 discs are SACD or DVD Audio. Many SACDs were printed with a redbook (16/44.1) image on the flip side.
SACD is 1-bit/2.8224 MHz, and can only be played back on SACD equipment. No drives were ever released for computer, to the best of my knowledge. Some SACD discs have a CD audio layer for compatibility (one of the releases of Pink Floyd's "Dark Side of the Moon" comes to mind), but that will be standard Red Book audio (16-bit/44.1kHz), and most often on the same side of the disc as the SACD version. Like dual layer DVDs, the laser for SACD playback can focus through the CD layer.

DVD-Audio is usually recorded in MLP (Meridian Lossless Packing), and is an encrypted format. I had an old Creative Soundblaster card that came with DVD-A software, but it was limited to Windows XP, and didn't allow ripping. A couple of albums lying near my desk have both CDs and DVDs with DVD-A, and they are listed as 24-bit/96kHz for the MLP. They also have DTS and LPCM versions, which are playable in a standard DVD player (with decoder for DTS). On those albums, both DTS and LPCM are listed as 48kHz/24-bit. It's fairly common for these "audiophile" packages to either have a separate DVD or, occasionally, Blu-Ray for the higher quality audio. Rarely, the package will be a DualDisc, where one side is CD and the other the DVD-A. These sometimes don't play right on CD players, however, because the CD layer is closer to the surface than on standard CDs.

There are certain CD manufacturers who claim 24-bit for their discs--but it's in the mastering stage. JVC's K2 and XRCD discs both use 20 or 24-bit masters at high sampling rates. The masters are converted down to 16-bit/44.1kHz (standard Red Book) when the glass master is made. One additional claim is that the process used for cutting the glass master is extremely accurate, and eliminates or reduces "time jitters". Sony's Superbit mastering system is similar, though I don't think that they claim the high accuracy in the CD manufacturing process. I'm guessing that ianm0's disc is probably one of these, or a similar process. The reason that it identifies as 16-bit/44.1kHz is because it's technically a standard Red Book disc.

As you note, some discs use HDCD encoding, and this does expand the information (using special dithering codes and playback algorithms) to 20-bit/44.1kHz. HDCD playback (but not ripping) is built into Windows Media Player 9 and above. DBpoweramp does have a good plugin to rip HDCD to 24-bit/44.1kHz FLAC, and will either leave the top 4 bits unused, or will shift all bits upward, depending on the DSP settings for the HDCD plugin. Ripping HDCD encoded discs using most other rippers (including MediaMonkey) will result in a 16-bit/44.1kHz rip of the standard audio, with any compression artifacts, but without the extra HDCD information.

MusicBringer
Posts: 622
Joined: Wed Oct 25, 2006 12:53 pm

Re: 24 bits 96 kHz CD question

Post by MusicBringer » Thu Feb 23, 2012 8:16 am

This is interesting.

I'd like a program that can display the bits and bobs and kHz's, the mp3 bitrate, the flac quality level and so on.
I think we have found that Explorer is not reliable and cannot display the truth.
I used to use old programs such as:
Mr Question Man http://www.burrrn.net/mrq/,
MP3-Info Extension http://www.mutschler.de/mp3ext/
Audio Identifier http://www.softpedia.com/get/Multimedia ... fier.shtml.

Trouble is these are rather old now and cannot cope with today's formats.

What is a modern easy to use program that will tell me the details of my music files.
Thanks,
MediaMonkey user since 2006

Ternaugh
Posts: 13
Joined: Fri Aug 10, 2007 4:05 am

Re: 24 bits 96 kHz CD question

Post by Ternaugh » Thu Feb 23, 2012 4:06 pm

MusicBringer wrote:This is interesting.

I'd like a program that can display the bits and bobs and kHz's, the mp3 bitrate, the flac quality level and so on.
I think we have found that Explorer is not reliable and cannot display the truth.
I used to use old programs such as:
Mr Question Man http://www.burrrn.net/mrq/,
MP3-Info Extension http://www.mutschler.de/mp3ext/
Audio Identifier http://www.softpedia.com/get/Multimedia ... fier.shtml.

Trouble is these are rather old now and cannot cope with today's formats.

What is a modern easy to use program that will tell me the details of my music files.
Thanks,
dbPoweramp has a windows extension which will provide an Audio Properties tab to the file properties. It will also show as hover text. It has things like size, original size, channels, sample rate (kHz), sample size (bit depth), bit rate, encoder, encoder settings, and so forth.

I use dbPoweramp as my main ripping tool, and MediaMonkey for playback and library organization. The dbPoweramp CD ripper tends to be faster than MM with AccurateRip enabled, and allows HDCD to be fully converted to 24-bit FLAC (20-bit, padded with 4 bits, based upon source limitations) with the paid version. http://www.dbpoweramp.com/

MusicBringer
Posts: 622
Joined: Wed Oct 25, 2006 12:53 pm

Re: 24 bits 96 kHz CD question

Post by MusicBringer » Thu Feb 23, 2012 6:14 pm

Thanks Ternaugh, yeah I now use dBpoweramp myself. It's very good, innit.
Just wondered if there was anything else around these days - that simply displayed the quality of a music file.
MediaMonkey user since 2006

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