What is SDI? SDI stands for Serial Digital Interface, and is a way to transport digital component video between video devices. In this instance, the video device that generates the component video is a DVD player and the video device that processes it is an HTPC.
Why is SDI beneficial? First, you do not lose any video picture quality as the video is transported. Second, the video is retimed upon arriving at its destination, so the video should be smooth. Third, SDI signals can be sent long distances without loss of quality.
What do I have to do to take advantage of SDI? In this instance, you need a DVD player and HTPC that both have SDI connections. DVD players normally don't come with SDI connections, so you have to
get one specially modified ($525 for the mod).
Until the beginning of this week , there haven't been any consumer-priced SDI input cards for HTPCs ($399 + s/h for the board).
What else is required for the HTPC to process the video? For best performance, for hardware you need a Radeon or GeForce 2 or higher video card and a CPU of about 800 MHz or greater. For software, you need the video processor application
DScaler and many will want to use
Powerstrip to dial in a good resolution and refresh rate for your display device.
Why bother with an HTPC, when you can get a good scaler that has better ergonomics? That is a very valid question, whose answer hinges on price and personal preference. Scalers are normally several times more expensive than HTPCs and/or have limited upgrade capabilities.
Why bother buying an SDI DVD player and SDI input card, when I can use WinDVD? Again, a very valid question. The answer hinges on many factors, of varying importance to each videophile. First, SDI appears to me to have a better image than WinDVD and the other software players. Second, SDI should have smoother video, especially on pans. Third, on video source materials and on improperly mastered materials, the DScaler video processor discussed above is superior to the software players.
There are other factors that you may consider. Normally, standalone DVD players have better controls than the software players. Also, standalone DVD players sometimes have other features, like DVD or SACD audio, for instance.
I want to input good quality analog sources to my HTPC. Can SDI help? Yes. There are SDI products on the market to convert to SDI from component, s-video, and composite. While not cheap, some of these solutions should produce fairly clean video for processing by DScaler.
What kind of cabling does SDI use? Standard 75 ohm cable with BNC connectors. Sometimes you will find 75 ohm cables with RCA connectors which will work OK too, if you buy two RCA > BNC converters. Better Cables sells appropriate cables, I think. Or you can use another
outfit .
My SDI input card only has one SDI input. Are there any switchers available? Yes, switchers for SDI are fairly inexpensive and are controlled in a varity of ways. Please see the
Poor Man's SDI Switch thread in the Video Processor forum for more discussion.
Why is SDI gear so expensive? In the past, SDI gear was used solely by professionals, where these prices did not affect how many people bought the gear. For videophiles, these rules no longer apply, and the community is making progress in keeping the prices affordable for the vast majority.
Will there be any way to get the SDI advantage with the DVD player in your HTPC? I don't know. The DScaler developers have looked at this a lot, but there appear to be challenges to making it happen at a satisfactory quality level for now.
Why is there so much banter in these SDI threads? Because everybody is happy. Previously, a videophile-good way of transporting video was unavailable for HTPCs. These methods revolved around doing an analog > digital conversion inside a PC case. A PC case environment is very interference-prone and resulted in "noisy" video.
More to come. I'll edit it in.