# Low latency video over IP



## Lextech (Jun 15, 2020)

Has anyone found a low latency video over IP set up? I'm not overly concerned about audio, just need to move picture as quickly as possible. Can be software, hardware or a combination.


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## MNicolai (Jun 15, 2020)

Crestron NVX or some of the low-latency ZeeVee products that are based on SDVoE. Probably similar products available from Extron/Atlona/etc but I haven't personally used them.

Lot of the higher end video over IP products you will only lose 1-2 frames in encoding/decoding and microseconds over the network. If you run at 60Hz, that would be half the latency you might have than running your video at 24 or 29Hz, so run at a faster frame-rate if possible.

Most of the actual latency occurs at the endpoints where the TV's process those digital video signals in. TV's should be set to "Game Mode" or have all the extra processing features turned off if you want the lowest latency over digital. Also helps sometimes to run at native resolutions without scaling -- especially scaling video in the TV itself.

There are plenty of lower grade sports bar type video-over-IP systems which have lots of latency -- this is an area where you generally get what you pay for.


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## Lextech (Jun 16, 2020)

Have you used the NVX gear with Dante?


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## MNicolai (Jun 16, 2020)

Yes, though there is a little oddity with that application. NVX doesn't play well on Cisco SG350/300 switches, which are the de facto standard switch used by most everyone for Dante.

From Crestron's support database:
_"Crestron recommends using the SG series switches in a single switch configuration only. This is due to limitations in the IGMP querier used within these switches. All multicast traffic must be contained within the single switch. For larger more complex switch configurations, we recommending consulting with a network design professional when architecting your specific solution."_

Not a huge deal -- Dante plays nicely on plenty of other switches, but if you're incorporating into an existing network I would be aware of that issue in advance.

One other consideration I would offer. If you want to treat this as a video switching system as opposed to just an extender over IP, I would go with Atlona, ZeeVee, or Visionary Solutions instead. All three of those play well with Q-Sys cores, so I imagine they are compatible with most other control systems you may want to use (Symetrix, Biamp, etc.). With NVX, you can certainly always manually log into the NVX units to set up routing but if you want dynamic routing via a control system you would need to throw an RMC-3 processor in the mix and have a Crestron programmer set it up to play nicely with whatever control system you might have -- which I would avoid in any portable/non-fixed/non-permanent application.


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## Lextech (Jun 16, 2020)

Visionary Solutions has a Duet Encoder & Decoder that runs on Dante but I can't seem to find out if i can choose any Dante stream as the audio as apposed to the HDMI audio.


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## MNicolai (Jun 16, 2020)

It's all assignable in Dante Controller.


> The DuetE and DuetD allow for the extraction and insertion of Dante™ audio onto and off of the Dante™ network. Each DuetE allows up to 4 channels of LPCM audio to be extracted and made available as Dante™ channels to the Dante Network™. Also, up to 4 channels of Dante™ audio may be inserted into the AV stream from the encoder and sent to any decoders tuned to the stream. Each DuetD may subscribe to up to 4 channels of Dante™ audio and insert that into their HDMI output instead of the AV stream audio. Each DuetD also makes up to 4 transmit channels of Dante™ audio available to the Dante Network from the AV stream audio being decoded.


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## Dan Fischer (Jun 24, 2020)

We use http://justaddpower.com/ for our video over IP solution and it's bullet proof. Plays nice with Crestron, AMX, C4 & RTI as well.


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## MNicolai (Jun 24, 2020)

Been a few years since I evaluated they product, but last time I looked at Just Add Power the latency was too extreme to use in the KVM application I was looking at it for. Would've made people nauseous trying to drive a mouse or type if they were watching the screen. I also vaguely recall their protocol for video over IP involved something along the lines of using network switches in a manner they weren't intended to make routing changes. Probably was back in 2015 since I looked at them last so they could be doing better these days but I would exercise caution and scrutiny before buying into their lineup.


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## Lextech (Jun 25, 2020)

Well I am getting Duet and Crestron demos soon and I will report back on how it goes. I actually asked "permission" from our IT department to borrow some unused lines between classrooms and the concert hall for testing. I love it when the stuff we do confuses the people who run the networks....


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## rwhealey (Jul 19, 2020)

I have had several successful projects with the AMX/SVSI 1000 series which has 10ms of latency, including virtual orchestra pits where this kind of thing is critical. They also have AES67 audio which works great with Q-Sys.

The bandwidth requirements are huge - I usually spec a Cisco 3650 switch as a minimum, but have been successful with the SG-300s.

Unfortunately, Harman seems to have stopped investing in improving SVSI. I’m not sure what the future of the product looks like.


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## MNicolai (Jul 19, 2020)

@rwhealey, I'm not sure it's Harman as much as Samsung that's driving the boat these days, Sounds like they've had an additional round of layoffs at Harman this summer.


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## EdSavoie (Jul 19, 2020)

I'm late to the party, but NDI is very speedy. By nature of the compression algorithm, it works better with 1080p or larger though. 720p and below tends to be a little wonky in terms of artifacts


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## Lextech (Jul 20, 2020)

So we did the test. All audio routed via Dante, CL-1 as control in the concert hall, RIOs in two classrooms. Video handled by Visionary Solutions boxes. Conductor and pianist in concert hall with camera feeding classrooms, mic on piano and a wedge. Vocalist in each classroom with a mic and a wedge. Audio was sent from each mic to the other two rooms, no signal in local wedge. Volumes were reasonable, not rock and roll but enough to hear the others comfortably. Note that neither singer is used to monitors, purely classical guys. We did one test piano and single voice and one with everyone. Video was a little slow, guessing 4-5 frames, but once people figured out that listening was not lagging they adjusted just fine. So my music department has decided that this is a workable solution if they need to split out into separate spaces. Now just trying to fit things into budgets and waiting to see the final university plan for fall.


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## Lextech (Jul 20, 2020)

I should mention that I used dry lines and a separate switch for audio and video.


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## MR_AV (Oct 22, 2020)

The IP-NINJAR series from IDK performs very well. It uses SDVoE (same as ZeeVee) and without using the scaler on receiver side the latency is below 200µs. They also have a bridge between SDVoE audio and Dante audio. 10G network is a must and the switches from Netgear play very well. M4300 and M4500 series are plug'n'play with SDVoE. For larger networks they introduced a technology called IGMP Plus, so you don't need to setup PIM routing. SDVoE uses a pixelpipeline CODEC, sending video lines as soon as they arrive to the encoder. The ACR (advanced clocking and resynchronization) technology allows the receiver to recreate the signal on the output same way as it came to the input of the transmitter. Each 10G switch on the path will add a latency below 10µs. If you do not need to scale the video you will always stay below one frame of latency.


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