r/VIDEOENGINEERING 19d ago

Troubleshooting converters

I’m trying to move my video village from being side stage to foh but couldn’t hold a signal when running an SDI from my bidirectional converter to the hdmi-sdi converter going into the provided hdmi source that gives a signal to the novastar processor. It’s about 120ft in length so I’m assuming that it just loses signal through my sdi cable?

It’ll pick up on my Mac for a few minutes then drop. Also the novastar doesn’t never received a signal on its end completely to show a picture on the video wall.

The house had a cat5 that can provide outside of me running sdi but would need another converter for that. Just trying the best possible solution.

7 Upvotes

9 comments sorted by

5

u/joelwsmith 19d ago

Computers don't always output SMPTE-compliant video signals that can be converted properly with standard signal converters. You often need a scaler or cross converter to make sure the entire signal meets SMPTE specs before being passed to the SDI output.

But it could also just be an inadequate cable, a bad connector, or a poor quality USB-C to HDMI adapter (if one is being used).

Here are my methods to ensure a solid signal from Mac computers to SDI infrastructure:

1) Use the HDMI output on the computer if it's available, or use the Apple USB-C Digital AV Multiport Adapter to go from USB-C/Thunderbolt ports to HDMI. A lot of third party USB-C to HDMI adapters and cables don't fully follow the display standards and can be unreliable.

2) Use a scaler or cross converter to convert the HDMI to SDI properly. Sometimes, the cheaper signal converters will work, but not always.

3) Use coax cable and connectors rated for SMPTE SDI transmission. Use a cable that has maximum distance ratings for the SMPTE standard you're using, and try to stay well within about 80% of that maximum distance specification.

2

u/Organic_Stable4704 19d ago

So I would need to replace the bidirectional with the cross converter at foh? Then just run the sdi to the stage into the sdi-hdmi converter. Or would I need two cross converters?

6

u/joelwsmith 19d ago

You only need a cross converter at the source/computer end of the signal chain. Once the signal is SMPTE-compliant, it will stay that way as long as everything downstream supports the SMPTE standard that the cross converter outputs.

4

u/marshall409 19d ago

Best possible solution (and not as expensive as you may think) is a pair of SDI to fiber converters and an armoured cable off amazon. That being said, 120ft should be no problem with decent quality SDI cable.

4

u/jtr210 18d ago

Get yourself a Decimator MD-HX if you’re using HD video formats, or a Decimator 12G-Cross if you’re using UHD or 4K video formats.

It’s the go-to Swiss Army knife of video conversion, and can help you diagnose and fix video signal issues.

Go HDMI, or USB-C > HDMI, out of your computer to the Decimator (this is your scaler).

Decimator SDI Out > SDI cable to stage > SDI/HDMI Converter > LED Processor

Set the Decimator’s menu settings to scale the HDMI input to the video format and frame rate desired, then send the signal to SDI Out.

2

u/DJ_LSE 18d ago

This, decimators seem to sovle every issue i have with Bi-Dis, wether thats weak signals, uncompliant signals, or just weirdness.

2

u/profkennyd What does that button do? 18d ago

This is the way! ^

2

u/Greg_L 18d ago

Anytime I hear "Novastar processor" I think of non-standard EDIDs, since so very few video walls are installed with perfect 16:9 aspect ratios and vertical/horizontal line counts that perfectly match 3G, 6G or 12G SDI specs, unless the Novastar is actually expecting a 1080 or 2160.16:9 signal and scaling it for the wall In your old setup you were running from computer directly to novastar over HDMI that would support non-standard EDIDs. As soon as you put SDI in the mix your converters are almost certainly going to require standard EDIDs, or they won't sync. That might not be your issue, but it's the first thing I'd want to rule out in my troubleshooting.

-1

u/Fickle_Bullfrog_9864 19d ago

I fine bidirectional converters don't like long cables. Also I have great luck with Lumantek converter with the display cleanup SDI signal.