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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Pro AV Forum => Topic started by: Josh Hoag on June 05, 2013, 12:13:10 am

Title: LONG hd cable run
Post by: Josh Hoag on June 05, 2013, 12:13:10 am
I need to run some type of 1920x1200 resolution cable from my macbook pro to a HD projector for my church.  The run will be anywhere from 75 to 100 feet.  I know about signal loss with HDMI so if your solution involves signal amplifiers I'm all ears. 

This is a new venture for me so don't blow me out of the water!

Thanks!
Title: Re: LONG hd cable run
Post by: Ryan C. Davis on June 05, 2013, 12:32:21 am
Well, 75 really isn't that long. 75 is almost doable with a regular cable but my general rule for thumb is to cap it at 50.

There are any number of HDMI over CATx baluns that will work fine though. My advice is to use a single CATx balun which only requires one wire as opposed to two. the twos work fine but you'll run into clock errors and other problems if you don't do it just right.

Lately I've been using the Atlona... http://www.atlona.com/ATLONA-HIGH-SPEED-HDMI-EXTENDER-KIT-OVER-SINGLE-CAT-5-6-7-WITH-FULL-3D-SUPPORT-1080p-up-to-130ft.html

It supports your resolution.

Kramer and Gefen both make solid units as well.

Title: Re: LONG hd cable run
Post by: Tommy Peel on June 05, 2013, 01:05:26 am
It should be possible to do this with VGA(HD-15) too; I looked up a splitter/signal amplifier on Monoprice (http://www.monoprice.com/products/product.asp?c_id=101&cp_id=10104&cs_id=1010401&p_id=3569&seq=1&format=3#specification) and it's rated at >150ft and a maximum resolution of 2048x1536. Not sure how this compares to the HDMI over CATx in terms of price, image quality, or reliability but it might be worth a look.
Title: Re: LONG hd cable run
Post by: Brad Weber on June 05, 2013, 07:50:30 am
I need to run some type of 1920x1200 resolution cable from my macbook pro to a HD projector for my church.
Is the projector native 1920x1200 resolution?  You are going to get no benefit and likely some negatives from sending the projector a signal with a higher resolution than the projector's native resolution.
 
The run will be anywhere from 75 to 100 feet.  I know about signal loss with HDMI so if your solution involves signal amplifiers I'm all ears.
You can look at special HDMI cables, video over CAT cable solutions, etc. but one thing to consider regardless of the type of cable used is the cable route.  If the cable will be run in conduit the entire length you may not need any special ratings but if the cable will be run in walls or above inaccessible ceilings, run through a riser, run through a plenum space, etc. then it need to have the appropriate rating for that use.  http://www.bluejeanscable.com/articles/inwallrating.htm (http://www.bluejeanscable.com/articles/inwallrating.htm) is a pretty good article on this topic.
 
Be careful of "up to" claims for distances and resolutions.  To use the device Tommy linked as a reference, it claims to support transmission distances "up to 100m" and resolutions "up to 2048x1536" but what does that actually mean?  For example, can you get a 100m distance, but only with 640x480 or lower resolution signals?  Or can you run 2048x1536 resolution signals, but only for 15'.  And how was the resulting signal being acceptable determined?  I am not trying to pick on that particular device as this type of specification is quite common but it is also something that less reputable manufacturers can use to their advantage.
Title: Re: LONG hd cable run
Post by: Jordan Wolf on June 05, 2013, 08:21:30 am
I need to run some type of 1920x1200 resolution cable from my macbook pro to a HD projector for my church.  The run will be anywhere from 75 to 100 feet.  I know about signal loss with HDMI so if your solution involves signal amplifiers I'm all ears. 

This is a new venture for me so don't blow me out of the water!

Thanks!
Josh,

I have found this extender unit (http://www.monoprice.com/products/product.asp?c_id=109&cp_id=10110&cs_id=1011012&p_id=8122&seq=1&format=2) from Monoprice to be very reliable.  It will allow for full 1080p @60Hz and the 100m distance with use of shielded Cat6 cable. It will also transmit IR, so you don't have to aim the remote in funky directions.

As Brad said, you will need to verify the classification of the cable if installing it; if this is temporary, you should be fine with "normal" cable. Monoprice's Cat6 STP only comes in blue for 100' runs; I was okay with that - you may not be.
Title: Re: LONG hd cable run
Post by: James Feenstra on June 13, 2013, 01:01:45 am
Hd/sdi is fine over runs of 75'-100' and should be easy to convert to....theoretically hdmi has no maximum signal length, but I wouldn't really run over 100' with it
Title: Re: LONG hd cable run
Post by: Brad Weber on June 13, 2013, 08:10:04 am
Well, 75 really isn't that long. 75 is almost doable with a regular cable but my general rule for thumb is to cap it at 50.
Hd/sdi is fine over runs of 75'-100' and should be easy to convert to....theoretically hdmi has no maximum signal length, but I wouldn't really run over 100' with it
I have definitely seen good results with much longer HDMI cables, however I believe that the HDMI standard defines a 15' distance and I have encountered devices that had problems with standard HDMI cables any longer than that.  I don't know if it is still the same but at one time even tested and certified HDMI cables allowed you to test a length and apply that to all cables that were identical other than in length, thus being able to test a 15' cable and apply those 'certified' results to 50' and 100' cables.
 
From experience, HDMI-to/from-HD-SDI conversion is not always easy.  I have not only runb into some fairly popular converter devices that didn't work as expected but HD-SDI does not support HDCP, making that a potential issue in some applications.  After a few bad experiences I just about always include a dedicated scaler as part of any HDMI-to-HD-SDI conversion so that you know there can be a stable and compatible signal to the converter.
Title: Re: LONG hd cable run
Post by: James Feenstra on June 14, 2013, 01:39:39 pm
Well by easy I mean its one piece of gear in line to do the conversion.

Something along these lines will work just fine; http://www.blackmagicdesign.com/products/miniconverters/

I've run 100' of hdmi straight out of a media server to a lcd tv without any sort of da and had zero issues

I generally do hd/sdi or dvi over fiber or cat 6 distribution though, as I'm frequently faced with much longer runs
Title: Re: LONG hd cable run
Post by: Brad Weber on June 14, 2013, 04:43:05 pm
Something along these lines will work just fine; http://www.blackmagicdesign.com/products/miniconverters/ (http://www.blackmagicdesign.com/products/miniconverters/)
They should work fine as long as the HDMI involved is a) one of the resolutions and scan/refresh rates supported by the converter (which are all 'video' and not any standard computer graphics resolutions), b) YUV color space and c) not HDCP protected (for HDMI-to-HD-SDI).
 
The color space issue is interesting as HDMI, I believe since v1.2, supports both YUV and RGB color space.  YUV color space is common in the video production and broadcast world while RGB color space is used in the computer graphics and digital media world.  Apparently Blackmagic and others coming from the production video side decided that since HD-SDI is YUV only then HD-SDI>HDMI and HDMI>HD-SDI converters only need to support YUV color space, so they do not include RGB color space support or color space conversion.  That's fine unless the HDMI source or destination is limited to or wants to be RGB color space.
 
In comparison, http://www.grassvalley.com/products/advc_g1 (http://www.grassvalley.com/products/advc_g1) accepts several common computer resolutions as well as standard 'video' resolutions and accepts YUV or RGB color space signals while http://www.grassvalley.com/products/advc_g3 (http://www.grassvalley.com/products/advc_g3) will output YUV or RGB color space.  Not pushing those specific products, just trying to show the differences between some HDMI/HD-SDI converters that may be relevant for some applications.  These kinds of details are often not relevant but when they do come up there may not be an easy fix other than changing hardware.
 
I also encountered one HDMI-to-HD-SDI converter that apparently wanted to see audio as part of the HDMI signal or it would not work properly.
Title: Re: LONG hd cable run
Post by: Jonathan Kok on June 27, 2013, 07:07:14 pm
They should work fine as long as the HDMI involved is a) one of the resolutions and scan/refresh rates supported by the converter (which are all 'video' and not any standard computer graphics resolutions), b) YUV color space and c) not HDCP protected (for HDMI-to-HD-SDI).
 
The color space issue is interesting as HDMI, I believe since v1.2, supports both YUV and RGB color space.  YUV color space is common in the video production and broadcast world while RGB color space is used in the computer graphics and digital media world.  Apparently Blackmagic and others coming from the production video side decided that since HD-SDI is YUV only then HD-SDI>HDMI and HDMI>HD-SDI converters only need to support YUV color space, so they do not include RGB color space support or color space conversion.  That's fine unless the HDMI source or destination is limited to or wants to be RGB color space.
Got burned by that one. Had to reconfigure the video design, since the damn BMD HDSDI->HDMI boxes wouldn't do RGB (which the projectors required). Laaaame...
Good to know about the GrassValley boxes.