# Adding DVI to existing Projection System



## jstroming (Mar 23, 2011)

Hey guys-

So I was tasked to add a DVI send from a a second output on a graphics card (from a Mac Pro, Win7 or similar) to an existing video system that is all composite (source to screen). Instead of downconverting the DVI to composite (which is going to look terrible for the text-based images) I thought it would be better to upconvert the composite feed to DVI via a switcher/scaler, utilizing that same switcher/scaler to select between the 2 inputs for output to the Projection Screens. So here's my playout/hardware tell me if you think this will work.

*DVI Source* & *Composite Source* feed into>
*Kramer VP-729 Scaler/Switcher* outputs HDMI to>
*Kramer VM-4HDCP DVI Distro* outputs DVI to>
*2x Gefen EXT-DVI-CAT5-MS Extreme Extender* outputs via CAT5 100' to receiver, then via short 3' DVI to>
*Projectors*

I can sacrifice a little bit of quality here, let me know if I am way off base with my thought process. Also, I know there is some difference between HDMI & DVI, and I'm using them pretty interchangeably here. Thanks!


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## JohnHartman (Mar 23, 2011)

Since you are looking at Kramer, I will stick with them...since you could argue numerous manufacturers who make similar hardware.

The 729 is not spec'd to support a true DVI in according to Kramer but can be adapted. Perhaps you should look at the vp-747 VP-747 - Scalers - Kramer Electronics. Then you can put the 2 cat-5e extenders right on the outputs program and preview if you don't need the preview option. or use the DVI-DA if you want to preview.

I would be concerned about any possible interface issues, DVI and HDMI have the same legacy heritage in terms of signal structure, but then you are depending on having DVI-HDMI cables and hoping the computer is not sensitive to the difference. 

In an overall what you picked out 'should' work but being conservative I would go with the DVI-DVI connection.

and I am always for cables that can be locked in and can't "walk" their way out of the jack.


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## museav (Mar 23, 2011)

Theoretically, the video signals on HDMI and single link DVI-D are directly compatible, of course "DVI" could also refer to DVI-A, which is comparable to analog RGBHV, or DVI-I, which handles both digital and analog video signals.

I'm not sure that using the VP-747 Preview and Program outputs instead of a DA is necessarily practical as these are two separate buses. The advantage of this is that you could route different inputs to each output, the disadvantages are that routing a source to both outputs would require making separate selection for each output and you would lose the ability to make any transitions between sources other than hard cuts.


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