Hdmi or VGA... And a bunch of other stuff!

[TheWordSpreader]

Hey I'm the sound tech of a small church and I am about to do some video upgrade to our computer.

Ok so at the moment I have a 256mb ATI radion graphics card and I am having problems with the computer shutting down when I play hd videos... I have come to the conclusion that it is a result of running out of memory so I plan to install a 1gb nvidia card...

Ok so the problem is that I'm not sure weather to keep running VGA to the projector or to go ahead and run hdmi... We also use a DVD player with hdmi capabilities... So my plan is to run the PC and DVD player into an hdmi switch and then to the projector which is a 75' - 100' cable run! Would I be better off sticking to the VGA connection from the PC and the RGB from the DVD player or go ahead and convert everything to hdmi?

Also we plan to add another projector in the future so if I ended up using hdmi I planed on just adding a splitter right before the projector since the projector has NO hdmi out...

PC / DVD -> hdmi switch -> 100' hdmi cable -> splitter -> 2 projectors

Is the hdmi setup a good idea or a waist of time and money? Also would I need a "hdmi booster"?

THANKS!!! ~Jason

[Paris MkVI]

I do not think you will be able to run HDMI that far - well, maybe with an active HDMI cable. Likely you'll need to convert to something - usually CAT 5 - then back at the projector. Someone like Magenta Research makes units for this purpose. I use these, but other manufacturers/options exist. You can learn a ton of stuff about HDMI here on Wikipedia.

HDMI also carries digital audio, which you likely do not need at the projector. On the digital video side of things, HDMI and DVI are identical - only the "plug" changes. So you might want to convert to DVI. You can get adapters for this purpose.

Why convert to DVI? Because DVI plugs can be latch or screw-connected for a secure connection. HDMI is a push/pull connector which, if it works loose, can be a little inconvenient - especially up at the projector location. That should not happen of course, but in our tech world a lot of things "shouldn't" happen!

[petereit]

If playing an HD video crashes your computer, it can be a whole HOST of reasons, but the video card wouldn't be my first suspect.

What are the total specs of the computer you're trying to play HD videos from? (how much RAM, how many processors, what type of processors, what version of OS are you running, how big is the hard drive, are there more than one hard drive, how much free space on the hard drive(s)?)

What kind of HD video are you trying to play from the computer? (What file format is it in and what codec does it use?)

What program are you using on your computer to play that HD video?

A 100' HDMI cable will not work without amplification (increases the signal strength) and equalization (makes the square digital waves square again). The general recommendation is an equalizing amplifier every 35', but with quality HDMI gear, you could most likely get away with running two 50' HDMI cables with an equalizing amplifier midway.

So your final signal path would be:

HDMI cable from PC, HDMI cable from DVD player into a 2:1 HDMI switcher.
50' HDMI cable from switcher to an equalizing HDMI amplifier.
50' HDMI cable from the amplifier to an active (powered) 1:2 HDMI splitter.
No greater than 35' cables from the splitter to your two projectors.

And unless you pay a lot of money for a really high-end HDMI switcher, expect the video on your screens to completely drop out when you switch from the PC to the DVD player (probably resulting in the projector's default "HDMI Signal Lost" screen to display for a second or two) then glitch a few moments while it syncs to the new HDMI signal source, and do it all over again when you switch back.

And, having said all that, you're still going to have fits with all the HDMI connections since they are not locking connectors. Any jiggle or bump of the cable can cause your entire signal chain to drop out.

(My background: we ran all HDMI everywhere in our church for over a year, including one 75' main "trunk", two 50' projector cables, multiple 35' cables, multiple 1:2 splitters, a 4x4 HDMI matrix switcher, and a very nice Gefen 1:10 HDMI distribution amp. We have since replaced almost all of our HDMI cabling with SDI cable, and if I had to do it all over again, I'd START with SDI.)

[TheWordSpreader]

PC Specs - windows 7, 4gb ram, amd processor (4 core I believe) running the videos (not for sure on the file type at the moment) with mediashout 4. Not for sure on the exact hard drive size but it is over 500gb with over 75% free space...

I didn't suspect the video card at first, but when I seen it only had 256mb dedicated memory I borrowed a nvidia card from a friend that had 512mb dedicated and the problem ceased (so far) and the only time the PC ever crashed was under "high" video demands...

How does sdi cabling work? Do I need a special video card or are there converters for something more common such as dvi? Would dvi have just as good of quality as hdmi and also I already have the cables ran for VGA would the increase in video quality be enough to justify rerunning a different cable?

[petereit]

To get SDI to work, you'd need a broadcast video card with SDI out, or you'd need a box to convert your signal to SDI, or as in our case, run a broadcast switcher that accepts DVI input and converts to SDI.

In your case, if you already have VGA run everywhere and it's providing good video, just stick with VGA. (Much, much, MUCH cheaper!!) But when the day comes that you want to run true HD everywhere, just spend the extra money and go with SDI. (See my profile pic? HDMI did that to me.)

You could eliminate the need for a switcher by eliminating the DVD player and just rip any DVD content you need to a video file in a format that works best with your presentation software. At first this can seem like a lot of work, but if you can nail down the workflow you can do it fairly quickly. We just had a guest minister who handed us a DVD as he was walking into the sanctuary to preach. We had it ripped and staged in ProPresenter in less than 5 minutes.

[TheWordSpreader]

Hey thanks for all the advice and thanks for answering all my questions. I'm a fairly new tech so this has been vary helpful along with all the information I read on this site!

[Brad Weber]

Some clarification since the terminology being used may potentially leading to misunderstandings. SDI is a robust transmission format with roots in the broadcast and production markets. A SDI signal can carry video information as well as ancillary data such as multi-channel audio and timecode and because of the intended use SDI has no inherent Digital Rights Management. However, "SDI" can be used to refer to SD-SDI (480i/576i), ED-SDI (480p/525p/576p), HD-SDI (720p/1080i), Dual Link HD-SDI (1080p) or single link 3G-SDI (1080p). "True HD" video including both 720p and 1080p are supported by DVI (-A, -D or -I), HDMI, VGA and SDI, however 1080p would specifically require Dual Link HD-SDI or 3G-SDI and not just SDI in general.

A factor for some is that to prevent direct digital copying of protected content the HDMI to HD/3G-SDI converters sold in the US are not permitted to be HDCP compliant. If you try to use them on HDMI source devices and the content or device activate HDCP you will just get snow. So this is not necessarily the best choice for computer, DVD, Blu-Ray, gaming devices, etc. if the device or content may ever include HDCP protection.

Unless everything in the path is HDCP compliant many of the same Digital Rights Management issues may apply to the conversion of HDMI to other signal formats. For example, there are HDMI-to-VGA converters avaiable but they are intended to be attached to a display device input, in effect turning a VGA input into a HDCP compliant HDMI input, and are not intended to be used to make the high resolution HDMI signal available for other purposes.

Off topic but I would also be careful with ripping DVD content, especially with guests. Playing a copyrighted DVD as part of a service may be covered under the religious service exemption and the original purchaser ripping a copyrighted DVD and then using that file rather than the DVD may be allowed. However, copying and ripping are not covered by the religious service exclusion associated with performance rights and I believe that copying protected content that you did not purchase or where it results in multiple copies having been created are not permitted.