DVI and HDMI Connections and HDCP Explained
Since the rollout of HDCP, there hasn't been very much, if any, consumer education. I think some of this might have been intentional, as products with non HDCP compliant DVI would be essentially useless. Read my article from 2003 if you haven't yet, it's a good reference on what is now the "standard".
Both major satellite manufacturers (Dish and DirecTV) are now using HDCP in the DVI connections with the satellite boxes. DVD manufacturers are required to use it for DVD-based material. Thus, if you really want to use DVI, you need to be HDCP compliant, from the source to the display. This means processors, buffers, amplifiers, and switches all must be HDCP compliant. If you bought an HD TV/Projector with DVI that doesn't support HDCP, you have a problem.
Unfortunately, consumers with analog displays are completely in the lurch, as many new video processors support DVI, but cannot display that content to the component video output. The DVDO HD+ video processor is a perfect example. Technically you could connect a DVI cable from a DVI output on a satellite box to the DVDO processor, scale, massage, and output it via component video in HD. But (and it's a big but) DVDO is required to shut off the component outputs when an HDCP encoded signal is present. It's frustrating, because HDCP licensing has tied the hands of premiere manufactures like DVDO.
To top it off, many projectors being sold today that have DVI still do not have HDCP (all HDMI devices are HDCP compliant). Make sure that if you buy a HD capable device and intend to use it with DVI/DVD, or DVI/Satellite, your projector has HDCP compliancy.
DVI-I and DVI-D
DVI-D is the same cable as DVI-I without the pins or wires to carry the additional RGBHV signal. DVI-D cables have 24 pins arranged in 3 rows of 8. One video signal requires 12 of these pins, meaning that your typical DVI cable can carry two video signals. Complicating this is the DVI-D Single Link vs. DVI-D Dual Link. We have found problems using Dual Link cables with DVD players and digital displays. So far, the Single Link seems to work fine.
Here is a link to a page that describes terms and compatibility of the numerous DVI connectors.
DVI-D to HDMI converter cables and adapters are inexpensive. This means in the near future that a single cable can be connected from each source to your home theater receiver, and then to the display device. Pioneer Electronics has been a proponent of HDMI technology, and their DV59-AVi was one of the first to market with HDMI jacks. HDMI will become the de-facto standard for home theater connectivity. One cable for both audio and video, and just one connector. You don't have to worry about Dual Link or Single Link, or D, I, or A variations like there are with DVI. At CEDIA 2004, new DVD players and projectors had HDMI, but no DVI, which means DVI is just about gone after only one year on the market.
From JJ's article on HDTV Repeaters:
DVI is an 8 bit RGB signal, while HDMI can be 8 bit RGB, or 8 bit, 10 bit, or 12 bit YCbCr. If you have a DVI source and DVI display, there will be no problem. If you have a DVI source and an HDMI display, again, no problem. If however, you have an HDMI source and a DVI display, the below-black video information may be lost in the translation. There is a bug in the Silicon Image HDMI transmitter that pops up when converting YCbCr to RGB. The HD TiVo and Pioneer 59AVi do not have this problem.
Even though source information (DVDs, HD) is all 8 bit color, if DSP is applied in 8 bit, such as in a video processor, rounding errors will toss out some of the data. On the other hand, if the data are 10 bit, such as with YCbCr, then the rounding errors don't occur. In fact, 14 - 16 bit is optimum for processing. Also, DVD data are YCbCr, and are converted to RGB in the player for the DVI output. RGB cannot represent all the data in YCbCr, and this is why the below-black information gets truncated.
If you have an analog component display, the good news is that most manufacturers are providing HDTV content over component video connections for the time being. If replacing equipment, make sure that you move to HDMI. The bad news is that content providers can (and will) pull HD content from component video outputs at some point, forcing HDCP on the masses. Expect HD DVD players to only support HDCP.
If you have an RGBHV analog display such as a CRT projector, trancoders can bring you to component video, but unfortunately nothing can bring you to HDCP. I hate to think that my Runco DTV-933 CRT display will at some point not be able to display HD content as HDCP gets enforced. But unless someone makes retrofit cards for our CRT projectors, there is no hope.
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