DVD-Audio Interview

Steven R. Rochlin interviews Jordan Rost who is the Senior Vice President of New Technology for the Warner Music Group.

 

Steven R. Rochlin: How do you see DVD-Audio being accepted by consumers?

Jordan Rost: We are extremely optimistic about the format and that is based on the consumers interest in sound quality and the acceptance of surround sound (20% of homes currently have surround sound system). The improvement is dramatic in sound quality as compared to CD...

 

SR: What advantages does DVD-Audio have over the currently available Compact Disc (CD)?

JR: DVD basic technology in its simplest form holds seven times the capacity of the CD. So when the music is digitized, the data that is captured is so much closer to the sound wave than what CD can do. So the resolution is greater (with the DVD-Audio Disc). Two advantages are:

1) Sampling rate and bit depth is more than double

2) Instead of squeezing things into 2-channel stereo, now they can place the music to six channels. In effect from an against the wall sound to that of more impact like in Carnegie hall. Sound does come from everywhere.

 

SR: Yes it does.

JR: Because of the flexibility and technology, we can give consumers more of what we can put on the disc. So if you are using a portable stereo unit, you get advanced resolution stereo. Put the same disc in your home surround sound system or car... and you'll have a fantastic experiences due to the surround sound ability.

 

 

SR: Are there any special recording/mixing technics used?

JR: A pop band might record to 48 tracks. This is all mixed down to two tracks.

 

SR: Right, a stereo studio master.

JR: When things can be spread around over six channels, more of the original recording can be heard in a blend that would be heard if consumers were in the studio or concert venue. It is less two-dimensional. They (studios) have experience with this as surround sound has familiarity with the concept.

 

SR: How does the two-channel "fold-down" work?

JR: Well, there was a concern when we designed the format. A high quality format like this, the audio professionals wanted assurance that the hardware would not make an arbitrary fold-down from the surround sound channels. To maintain the quality control of the fold-down of the stereo playback. The format allows two different approaches.

One is an exciting approach called "Smart Content". That is simply when the mixing engineer determines how the six channels fold down to two. Then instructions are placed (on the disc) to guide that fold-down operation as a data stream on the disc so that all the DVD-Audio players see "Smart Content" instructions. The players are required to follow those instructions. That also saves a lot of disc space to enable all the content to be placed on one layer versus two layers.

A separate stereo mix could also be placed on the DVD-Audio disc as well. In either case the player will not do an arbitrary fold-down so the stereo quality is assured. If you have an existing video player, the DVD-Audio disc will also be able to play the DVD-Audio disc through Dolby processing.

 

SR: And now the million dollar question, how about copy protection?

JR: This is not about copy protection as consumers are going to experience better audio and features, discography, lyrics, etc. We licensed the 4C technology for watermarking/encryption which sis seamless for consumers. We maintain 100% quality control.

I would say that really to understand and appreciate DVD-Audio, someone that cares about music will get it right away by listening. They will appreciate it even in an average quality surround sound system. There are a number of stores already who have players out.

 

 

Post Interview Information

DVD-Audio is the most recent addition to the WG-4 approved DVD family of pre-recorded optical disc formats. The full version, 1.0, was released in April 1999 (version 0.9 was released in June 1998) and today there are many manufactures making unit that will play DVD-Audio discs. Mainstream online/mail order retailer Crutchfield offers two units.

The Technics DVD-A10N DVD-Video/DVD-Audio/CD Player for $999.95 and the Panasonic DVD-A7 DVD-Video/DVD-Audio/CD Player $799.95 (all are "street prices" which are lower than manufacture's suggest retail pricing). Sony's proprietary Super Audio Company Disc (SACD) is not an industry standard format and not approved by the WG-4. Therefore very few major labels are supporting the format. Yes, Sony has quite a large catalog of music to choose from, yet it is small in the world marketplace when we look at the entire recording label industry.

The DVD Forum working group WG4 consists of 38 members. These members have worked together in the development of the DVD format. After much research and debate, the WG4 chooses what is going to be part of the DVD format. The approved DVD-Audio format offers a wide variety of both audio and video functionality (unlike SACD). DVD-Audio discs have the ability to offer video, still pictures, lyrics, menu interactivity. The "still pictures" mode allows for still pictures that are in the MPEG-2 Intra-frame and can, optionally, be accompanied by a subpicture for a menu. Transitions for still images include cut, fade, dissolve and wipe. Two modes are possible such as "slide-show" mode where the still pictures are displayed as they are loaded from disc while the audio is playing or "browsable mode" where up to 19 still pictures are pre-loaded into buffer memory before the audio starts and can be displayed under user or program control.

Another feature is "text information" for the contents, artists' names, Internet URLs, lyrics etc. Of course static text information can be employed for overall content while a more dynamic type text can be used for updating, say the song lyrics as each song is played. As for additional video content, various video clips are also allowed though, of course, the audio part of the video may be presented without the video as the recording labels so chooses.

On the audio side of things, there are many choices a music label can choose from. Multiple channels of sound at various bit and sampling rates plus unique two-channel "fold down: for those who choose stereo audio reproduction over a more multi-channel sound. Due to the dual layer structuring of the DVD-Audio disc, at least 2 hours for full surround sound audio and 4 hours for stereo audio can easily be handled. In the single layer capacity will obviously offer approximately half these times. For detailed specification please see the chart below.

 

DVD-Audio Specifications Below

Channels of Audio	Bit Rate	Type of Disc
		12 cm (normal)		8 cm (small)
		Single Layer	Double Layer	Single Layer	Double Layer
2-channel	2kHz/24-bit	258 minutes	469 minutes	80 minutes	146 minutes
2-channel	192kHz/24-bit	64 Minutes	117 minutes	20 minutes	36 minutes
6-channel	96kHz/16-bit	64 minutes	117 minutes	20 minutes	36 minutes
5-channel	96kHz/20-bit	61 minutes	112 minutes	19 minutes	34 minutes
5-channel + 2-channel	96kHz/24-bit + 48kHz/24-bit	43 minutes	78 minutes	13 minutes	24 minutes

Alas, all was not perfect as the Content Scrambling System (CSS) used in DVD video players was "hacked" which seemed to cause a delay in the launch of the DVD-Audio format. Since DVD-Audio players are designed to use the newer CSS2 system, a very different copy protection scheme from the original CSS is employed. Furthermore, other types of encoding and watermarking are also in the works.

In our interview with Jordan Rost, Senior Vice President of New Technology at Warner Music Group, the 4C protection scheme is being employed.

The 4C group is composed of IBM, Intel, Matsushita and Toshiba and works with the Copy Protection Technical Working Group (CPTWG). These companies have been working closely with many of the major recording labels to offer a very transparent yet secure protection system. i will avoid the specific details of various forms of using C4 and the Verance Watermark and simply agree with Jordan Rost, hearing will be believing, and as always...

Enjoy the music,

Steven R. Rochlin

PS: For specific details on DVD-Audio, please see the WG4 Fourm's PDF file titled Recommendation for DVD-Audio .