Film-Tech Forum ARCHIVE: laptop guest inputs (DVI, etc.)

This is topic laptop guest inputs (DVI, etc.) in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Scott Norwood (Member # 30) on 09-24-2010, 11:31 AM:

What is everyone doing for laptop guest inputs at the lectern location in new multi-use facilities?

A few years ago, these would have all been HD15 VGA, with 5-wire coax to an Extron (or similar) switcher and/or scaler to a video projector. Easy, simple.

While VGA inputs are still necessary, laptops are increasingly coming with DVI and/or Displayport outputs. Is anyone installing DVI guest inputs? If so, how do you get around the 25-foot DVI run length limit? Do you convert the signal to HD-SDI at the lectern and run coax to the booth? Are there DVI signal amplifiers that can extend the signal range?

Posted by David Zylstra (Member # 4230) on 09-24-2010, 01:37 PM:

I have not used them yet for a long run of DVI or HDMI but Rapid Run has cables with active "flying leads" that extend DVI and HDMI connections.

I have used their cables for a long VGA run and they work well.

Posted by Sean McKinnon (Member # 612) on 09-24-2010, 02:18 PM:

I used to conver DVI to HD-SDI and run on coax back to the booth.

Posted by Kris Verhanneman (Member # 5562) on 09-25-2010, 02:42 AM:

We still use de VGA connection when they place the pc in the auditorium (we have 2 sets of VGA over CAT5 cables).

When the pc is in the projection room we use HDMI/DVI or VGA when HDCP problemes occur.

I do hope that we can add a 100m optical DVI cable to our gear.
On our largest screening rooms it would be usefull Just trying to get the money for it...

Posted by Steve Guttag (Member # 268) on 09-25-2010, 07:37 AM:

There are several means of breaking the 15' barrier of DVI/HDMI. Better cables w/equalizers is one way but it gets expensive and getting those cables routed can be difficult. The DVI over Cat 5 solutions are attractive since CAT 5 pulls easily in conduit. And, in the case of Extron, it also adds RS232 connectivity without pulling an additional cable.

http://www.extron.com/product/product.aspx?id=dvi201txrx&s=0

If you use shielded Cat 5 (STP) cable, you can get up to 200-feet with typical resolutions (note they make an HDMI version, which also supports HDMI audio).

This year, they introduced "the bomb" for covering your basis.

http://www.extron.com/product/product.aspx?id=tphdutad&allparts=1

The problem with Cat 5 solutions is the distance versus resolution...which can be out of your control. That is, you don't know what the resolution is going to be if you are renting the theatre and 1080p/60 tends to have a much shorter distance than traditional XGA (1024x768) resoltion which can often get a couple hundred feet.

As for SDI solutions, you are then forcing the resolution to fit into an SDI known frequency/resolution. SDI should be able to get just under 300-feet before a repeater is necessary to refresh the signal though.

For DVI, one can also convert to analog RGBHV and transmit using traditional means (or existing infrastructure). For most "Power Point" presentations, this should be sufficient. I've had mixed results from the conversion in terms of color accuracy.

Crestron has a whole family of dealing with DVI/HDMI in their "DM" series. Not cheap but they can get pretty long distances and incredible control.

The end-game, for the foreseeable future is fiber. Fiber extenders normally rate their distances in MILES, not feet and most any resolution in use today. The hitch there is cost. The fiber cable isn't so much but the boxes at either end are still pricey, in my opinion.

Posted by Scott Norwood (Member # 30) on 09-25-2010, 11:57 AM:

That Extron thing looks ideal for this purpose. The run length (stage to booth) should be in the 100' range.

Steve--I'll be in touch about this if/when the venue in question decides to actually buy this stuff (within the next year, I hope).

Posted by Daniel Morez (Member # 5787) on 10-13-2010, 01:40 PM:

We (colleagues and I) have had good results with Aven View brand optical extenders,

Aven View DVI extender