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.
[quote="mcow"][quote="Eyal"]Standard [u]Audio CD[/u] is 16-bit/44.1 kHz. What you have is an [u]HDCD[/u] 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.[/quote]
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.[/quote]
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.