[SOLVED, HARDWARE ISSUE] Occasional video corruption - failing video card?

  • I'm having some problems troubleshooting the setup for my current show.  I've got 4 projectors, each with their own different connections.  The one I'm having problems with is connected to an Aurora VLX-TC1-C video over IP, via an active minidisplayport to hdmi adapter.  I'm having intermittent loss of signal at the Aurora, as well as some corruption to video.  I've included a video of what I'm experiencing.  As you can see in the video, I seem to be having more trouble when I try to adjust any parameters, for instance when I adjust the contrast (within Isadora).  It seems to be a hardware issue, my cycles and FPS don't seem to be suffering with any changes I make.  I've heard of graphics card problems with the trash can Mac Pro, but it also doesn't really look like graphics card problems I've seen in the past.  Does that look like what's going on here?  Or could it be a problem with Aurora unit?  Maybe maxing out cable length?  Has anybody experienced anything like this?  I'm stumped...

  • Beta Gold

    Maybe it can be a ground loop issue with the video over IP? Do you use a CAT cable from the house or dedicated? A switch in-between?

  • Tech Staff

    @knowtheatre said:

    Aurora VLX-TC1-C

    Even though I don't have experience with this piece of hardware in particular, since you say you're getting signal loss, my bet is also that this is a hardware issue. Looking that piece of tech on the web turned up some tips: 

    "Note: The selected network switch needs to support:  1Gbps, Non-blocking IGMP & Jumbo Frame Packets. The raw network cabling as well as the patch cables are as important as the switch. When using copper, CAT5e, 6, or 6a cable is preferred for optimal performance and is important to follow the standard rules for running Ethernet cables. No sharp bends, coiling, putting near power lines, grouping tightly together with other LAN cables, etc. Shielding is not necessary but can be used for noisy environments."

    I'd also check the manual and see if there's a max distance it can go at the resolution you're using. (I once had an extender that boasted of being able to handle a 1080p signal and extend a signal up to 150 feet and came to find out, after much frustration and deep reading into the manual, that it supported 720p at 150 feet but you could only go 75 feet with a 1080p signal. Technically, they were correct in both of their claims, but when purchasing the product you didn't have access to the manual and were likely to assume that one could use it to extend a 1080p signal for 150 feet.) So maybe try using media of a lower resolution and see if that helps. (Also remember that sending 4k video to a projector only capable of HD [1080p] resolution is just a waste of computing power, so the "best" resolution possible isn't always the best option.)

    If you need to reduce the cable length, in extreme cases you can move the computer closer to the output device, then run ethernet cable from the computer back to another switch, then run another ethernet line from the switch to your tech table/booth then access the show computer remotely. I tend to have my show computer in the booth from day 1 and use a switch to access it remotely with my laptop from the tech table so that come time to dismantle the tech table, I don't have to unplug or replug anything from the show computer, thus eliminating the possibility of having to do any last-minute trouble-shooting.

    Best wishes,


  • @woland, after double-checking that the switch was up to spec, it was indeed a cable length issue.  We reduced as much length as possible to get us through tech rehearsals, and the dropouts were significantly less often and less extreme, although we still had the occasional signal loss.  Once we moved up to the booth, we've had no more issues.

    May I ask what set up you use to remote back to the booth?  I would love to keep everything up in the booth, and I use teamviewer to make small edits once the tech table goes away, but the lag time would drive me insane if I were to program an entire show that way....

  • @knowtheatre using teamviewer with a gigabit lan connection is very smooth for me. You need to enable incoming lan connections, you can also do this without internet. It will work pretty well over wifi, but I am not a fan of lag so hid a lan cable somewhere convenient for this purpose. Check out digitial snake/tactical lan or cat7 sftp cabling. It is shielded and rugged and can often get you more distance out of these kinds of extension systems.

  • Tech Staff

    @fred said:

    I am not a fan of lag so hid a lan cable somewhere convenient for this purpose

    Exactly what Fred said. I put the show computer in the booth and wire it up to a gigabit ethernet switch then run ethernet cable to the tech table for my laptop.

    On Mac you can also do screensharing this way (wired or wireless but I prefer wired): http://osxdaily.com/2012/10/10/remote-control-mac-screen-sharing-os-x/

    I only tend to go wireless when I'm bringing my laptop up onstage to fine-tune the mapping (and even then I'll stick to a wired connection if I can manage to do so).

  • @fred aha!  I think enabling lan connections did the trick.  I can't believe I've been dealing with the lag this whole time, and it was something so simple!  I also don't know why that option wouldn't be enabled by default...

    @woland, I think I've mentioned this before, but I often encounter a bug when using Mac's VNC.  It's like the client computer doesn't properly recognize the arrangement of the host computer's displays, and when I try to click on anything to edit, the cursor is actually on another screen.  https://discussions.apple.com/...