As I have been asked to make a comment on this thread, I will attempt to give a brief response. Since this thread is titled "CD Players that transmit 24bit/96kHz" we should address this aspect first. In a word, there are none. CD players (as opposed to DVD-V players) output 16 bit - 44.1 kHz data as this is the ONLY data that a CD contains. As for DVD there are basically two flavors. DVD-V and DVD-A. DVD-Video is a format that was released in 1997. DVD-V has within its specifications the following types of audio capabilities: Dolby Digital, DTS, MPEG and LPCM. It is the LPCM capability that allowed our group (Advanced Audio Disc) to launch the series of 24 bit 96 kHz discs and players that we introduced in January of 1998. When a disc is authored, a decision to "allow" the data to exit the chassis "in the clear" is made. As I did the authoring on many of the Chesky and Classic discs (and have been involved in the many of the others) I can tell you that all these discs allow the output of non - degraded data. Should the content provider choose to prohibit data transmission, the player is still allowed to output data in a degraded fashion. This involves limiting the sample rate to 48 kHz and the sample size to 16 bit (this is basically DAT quality). These limits apply equally to all players using bi-phase interfaces (S/PDIF, AES, etc). An exception would be the use of an interface that protects the data (by encryption) such as the Universal I2S. DVD-A is a new format that in many ways is similar to DVD-V with a few small (but notable) exceptions. DVD-V has a data rate limit of 6.144 Mbits for the audio portion of the stream. This allows for a stereo pair of 96 kHz - 24 bit audio channels. DVD-A has the same audio capabilities that I previously mentioned, but adds MLP and increases the audio data rate limit to the full capacity of the disc (9.6 to 9.8 MBits per second). It is MLP or Meridian Lossless Packing that allows DVD-A to accomplish 6 channel 96 kHz - 24 bit surround. DVD-A also has the capability to handle 192 kHz - 24 bit 2 channel, but I know of no content providers even considering this as a consumer format. Frankly, there is almost no quality improvement going from 96 kHz to either of the 2 higher (176.4 or 192 kHz) data rates that DVD-A allows. The main thrust behind DVD-A is its multi-channel features. In getting back to the theme of this thread, I should point out that there is no intention to allow DVD-A data to be output by a bi-phase interface, only via its analog outputs (protected interfaces aside). A DVD disc can contain content in both the DVD-V (VTS) and DVD-A (ATS) structures so as to be playable on both types of players. This is the intention of nearly all content providers as they fully understand the difference in the installed base; specifically that DVD-A capable players exist in few thousand homes, while DVD-V capable ones make up the rest of the estimated over 80 million devices (players, computers, automotive, portables, etc). I will take a minute here to announce that the work being done by Chesky Records in promoting the 6.0 format is something that is worth watching. This format is so clearly superior to simple stereo and other forms of surround (Dolby Digital, DTS) that I won't even attempt to describe the differences, as I can't find adequate words to convey the scale of the improvement. Kevin Halverson
