Digital DVD Video Right Now
Dear Gary: In Alan Koebel’s article on “Digital Video Interfaces And Consumer Displays” in Issue 47, he asks: “Is either SDI or its high definition sibling likely to be used in consumer equipment?” His answer is “a definite no.” However, the facts say otherwise. As noted by Richard Hardesty in the same issue,Theta Digital “used a serial digital interface to connect their DVD player to a huge professional digital projection unit for an impressive, all-digital-video “home theatre” demonstration at the last CES. Theta has offered an SDI output option for their DaVid II and Carmen DVD players for several months. German Vigatec sell a DVD player that they call the DVD-MAX (an SDI-modified Pioneer DV-37, known outside the U.S. as DV-737) to go with their video scalers which offer an SDI input as an optional extra. Electrograph Delphi already offer SDI inputs on their plasma displays. The first U.K. reviews were published last summer. And Manh Nguyen of Crystalimage of California informs me that they will add SDI in/out to their video scaler this year. So “a definite no” seems a bit exaggerated. Inspired by the Theta presentation in Las Vegas, I recently borrowed a Vigatec DVD player and scaler for an article for High Fidelity magazine (Denmark/Sweden) on the politics and the potential of SDI. The difference is not subtle. It is also heartbreaking to discover the true signal quality available NOW from DVD, if only the paranoid intellectual property owners would allow us to bypass two crippling stages of digital-to-analog and analog-to-digital conversion. I hesitate to describe the stability, clarity and color purity of a direct digital SDI connection for fear of arousing disbelief. I strongly suggest that your readers and staff take any given opportunity to experience SDI DVD and I hope that this format succeeds at least as a high-end alternative, in keeping with your magazine’s credo to make home theatre “the best that it can be.”
Al Jones,
mailto:leemedia@mail1.stofanet.dk
Contributing Editor Alan Koebel Comments:
I should have been more clear in my statement about SDI, which I intended to be interpreted within the larger context of the article. I did not mean to imply that we will never see the interface on consumer equipment (your examples clearly show that is not the case), only that it will never become widespread. The likelihood that SDI will be offered by the major CE manufacturers on equipment intended for consumer use (two important distinctions) is small in the extreme, for the reasons I stated in the article. High-end and other small-run manufacturers such as those you name (some of who modify equipment from the major manufacturers) can get away with it; they aren’t a real concern to the content providers precisely because they ARE small. Neither does the presence of SDI on commercial and professional equipment cause much concern. Some of these products, offered through value-added resellers like Electrograph Delphi, will indeed find their way into homes, but not in large numbers. The original manufacturers of these products never intended them for consumer use. As one who designs high-end and professional projection equipment, I have a lot of experience viewing SDI—albeit from sources such as D-5 and Digital-S VTRs, not DVD players—so I do appreciate the signal quality that this digital interface makes possible. But SDI is not a panacea. For one thing, it only transmits standard-definition signals (which means SDI output from a scaler is of questionable utility). HD signals, in particular, require a different interface, such as SMPTE 292M that uses different transmitter and receiver chips (a combined interface is possible, but expensive). And SDI does not lead to “virtual HDTV image performance” as one manufacturer of scalers with SDI input claims. Even when using analog component, true HD is much better than scaled standard-definition regardless of how the latter is connected (provided the display device is capable of showing the difference). Finally, describing the two stages of respective D-to-A and A-to-D conversion required for an analog connection as “crippling” is, in my opinion, overstating the case. I too would prefer they not be present but, with careful design, excellent image quality can still be achieved.
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