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Author Topic: HDMI distribution amp and cable run problems  (Read 4213 times)

Andersongates

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HDMI distribution amp and cable run problems
« on: March 12, 2013, 04:02:57 pm »

My company has been making the switch to full high def shows. We deal with mostly corporate events in hotel ballrooms.

What we are currently doing is using computers with HDMI outs into the black magic 1m/e (which I love), then splitting it with a Kanex 1x4 da, then to vanco 2x cat5 transmitter/receivers which should cary hi def 100', then to our high def Sanyo projectors or a wide variety of flat screen monitors.

The problems I have run into is mostly when using the monitors but I've seen it once with the projectors in less than a 100' run. What I get is a flicker. A 3 second black screen then the image is restored. The image always looks great, just the flicker. And the longer the run, the worse it is. In the projectors case only the one further away from the source was the one to flicker. If I introduce a second da after a 100' run, forget about it. Flicker time, so everything so far has had to be home runs.

If I bypass the da, there is no flicker, but the black magic only has 1 HDMI out so a DA is more than a necessity as I have had shows with 5 monitors. In my head I am thinking my distribution amp is too cheap and is overheating or something. What I can't figure out is what the more expensive da's provide. And should I just trust a bigger name brand?

I'm also wondering if HDMI to HDSDI would be a better/easier application because you only have to run 1 cable. Not sure is anyone has run into this problem or has any knowledge that could help me out.

Thanks,
Anderson
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Christopher Young

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Re: HDMI distribution amp and cable run problems
« Reply #1 on: March 14, 2013, 08:30:35 am »

I ran into almost the exact same problem a couple of years ago with a brand new Crestron DM system.  We sub contracted the install (bad decision, not mine) and the AV company could not solve it.  In our case, it was happening in two separate scenarios.  One was too low a resolution from the source (composite in from DVD/VCR) not being handled by the projector.  In the other it was a mismatch between the EDID table in the projectors and the source.  I'm guessing in your case it's either EDID or HDCP problems.  Info is being mangled or not passed by the DA. I would suggest you get the Extron EDID reader, or Moninfo and load it on to your laptop, then take a look and see what you are getting from the projectors with the DA in and bypassed.  That will at least give you a bit of info to work with.

Good luck


My company has been making the switch to full high def shows. We deal with mostly corporate events in hotel ballrooms.

What we are currently doing is using computers with HDMI outs into the black magic 1m/e (which I love), then splitting it with a Kanex 1x4 da, then to vanco 2x cat5 transmitter/receivers which should cary hi def 100', then to our high def Sanyo projectors or a wide variety of flat screen monitors.

The problems I have run into is mostly when using the monitors but I've seen it once with the projectors in less than a 100' run. What I get is a flicker. A 3 second black screen then the image is restored. The image always looks great, just the flicker. And the longer the run, the worse it is. In the projectors case only the one further away from the source was the one to flicker. If I introduce a second da after a 100' run, forget about it. Flicker time, so everything so far has had to be home runs.

If I bypass the da, there is no flicker, but the black magic only has 1 HDMI out so a DA is more than a necessity as I have had shows with 5 monitors. In my head I am thinking my distribution amp is too cheap and is overheating or something. What I can't figure out is what the more expensive da's provide. And should I just trust a bigger name brand?

I'm also wondering if HDMI to HDSDI would be a better/easier application because you only have to run 1 cable. Not sure is anyone has run into this problem or has any knowledge that could help me out.

Thanks,
Anderson
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Brad Weber

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Re: HDMI distribution amp and cable run problems
« Reply #2 on: March 14, 2013, 02:39:17 pm »

With the ATEM all inputs and outputs are assigned a single resolution and refresh/scan rate.  The default is 1080i/59.94 and the other options are 720p/59.94, NTSC (SD), 1080i/50, 720p/50 and PAL (SD).  525i/59.94 and 625i/50 are also available for anamorphic SD.  That means that unlike many HDMI sources the ATEM will not read the EDID of the attached devices and match its output to them, its output is set in its configuration and all of your sources and displays have to be compatible with whichever one of those options is selected.

The ATEMs don't support HDCP.  It is usually more relevant for sources, however if something looks for a HDCP handshake it will not get it.

But I'm not sure EDID or HDCP are the issue.  It sounds like the problems occur only when the DA is inserted and primarily for the displays with longer cable runs.  That makes it seem like a signal loss issue caused by the DA and technical data on  the existing DA may be difficult to find.
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Andersongates

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Re: HDMI distribution amp and cable run problems
« Reply #3 on: March 17, 2013, 04:47:50 pm »

Yes I definitely think its a problem with my da. It was an inexpensive unit sold in a local store. I would like to upgrade my da, do I just trust a bigger name brand? Should I just trust the price? Meaning the more expensive just must be better?

I was also wondering about the units that would take the one hdmi output and split it to numerous cat5 immediately such as the atlona AT-HD19SS. Rather than splitting the hdmi 4 times into separate extenders for each send. Does anyone have a success story about these units?
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Christopher Young

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Re: HDMI distribution amp and cable run problems
« Reply #4 on: March 19, 2013, 08:18:50 am »

I don't think there's much question as to whether it's the DA that's at fault or not, it's why.

It may or may not be an HDCP problem, or EDID, although based on what Brad said regarding the ATEM, I would doubt it has anything to do with EDID. (I'm not familiar with this piece of gear)  I've so far had personal experience with the Kramer transmitters and the Crestron DM both the new and old, and we had a contractor install a bunch of Extron stuff that I had no personal contact with.  I tend to like Extron stuff in general, but in this case they could not get it to work, and I think it all got replaced with the next generation stuff.  I'm not sure price can be your guide on this.  I've also used (only once so far) the new Digital link system that Panasonic is selling, and in a demo seen is work straight out of a Crestron DM, and I have installed it in a room using their own switcher/scaler (Panasonic ETYFB100G) and it worked flawlessly.  So far I don't know of any projectors using it other than Panasonic, but it is slick, basically the receiver is built in to the projector, and it also caries the control protocol so no RS232 connection is required at the projector end.

If you're going the TX/RX route, you really need to go Cat6e, and it should be crimped with the best crimpers you can afford.  More than once we've had funky performance that turned out to be a bad Cat6 crimp, and re crimping fixed the problem.  We now have a couple of the Crestron crimpers and we're using their connectors and termination problems have been eliminated.

On shorter runs, (less than 75') I highly recommend forgoing the cat6 route completely and using the Blue Jeans BJC Series1 HDMI cables straight through.  I've run several at 30 to 50' distances and they are solid beyond 1080p. (Blue Jeans claims 1080p at 75' but I haven't gone that far)  These are special "bonded pair" cables that were developed in a joint venture between Belden and Blue Jeans and the only down side for me is that they are not plenum rated so they must go through conduit.  http://www.bluejeanscable.com/store/hdmi-cables/hdmi-cable.htm



Long answer to a short question but there you go.  I have no experience with Altona stuff at all so I can't comment on that. Good luck.

Chris
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Andersongates

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Re: HDMI distribution amp and cable run problems
« Reply #5 on: March 19, 2013, 08:23:36 pm »

I understand HDCP and why it exists, but almost all of our shows are run on MacBooks or dell's with HDMI outs straight into the ATEM. Just power points or keynotes and in house movies. Never anything that would be protected.

With that said does this eliminate my need to worry about HDCP issues?
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Christopher Young

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Re: HDMI distribution amp and cable run problems
« Reply #6 on: March 20, 2013, 08:00:15 am »

Yes and no. 

Certain laptops (mini Mac is a usual suspect) turn on HDCP regardless of content being presented.  I haven't had enough experience with this yet to know exactly how to deal with each machine, but apparently if you know where to look, you can turn it off.  So far we've been dealing with it by ensuring all our gear is HDCP compliant, because we simply don't have the staff to run all over the place showing people how to turn it off on their laptops.  (assuming we knew how in all cases)  If you're using the same machines for every event you should be able to deal with it at the laptop end.  In my case, (University campus) I would much rather run SDI everywhere and pass completely on HDMI.  Unfortunately we have to support protected content for playback on Blue Ray in our installations, so until something better comes along I'm being dragged kicking and screaming into the HDCP compliant world.   

I understand HDCP and why it exists, but almost all of our shows are run on MacBooks or dell's with HDMI outs straight into the ATEM. Just power points or keynotes and in house movies. Never anything that would be protected.

With that said does this eliminate my need to worry about HDCP issues?
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