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Audio over internet protocol (IP) got all the press at one point in time. But video over IP, specifically, is the rising topic of the moment. With 2022 freshly upon us and world events of the past two+ years opening our eyes to all the new ways that churches can use video to connect with those outside (and still inside) their walls, IP video workflows—their scalability and affordability, the ease of storage and access they engender, and the ultimate creativity they unleash—are the hot topic for churches that want to start strong in 2022.
Yet, with any growth spurt comes growing pains, and as a church tech, you know this all too well. In the following report, CPM starts from scratch and builds out informationally from there, so that churches can see where they are in the progression of working toward what video-over-IP might look like internally in their own production workflows. And from there, tech leaders can understand and envision the next logical steps to propel their workflows forward, keeping an eye on newer emerging technologies for video-over-IP, such as NDI (now on version 5), SRT (Secure Reliable Transport), Dante AV, SMPTE ST 2110, and others.
So where do we start? Maybe the best way to ease into this techno world of signal distribution is to start with the original way of getting audio and video from Point A to Point B, then move on.
What is SDI and why not HDMI?
A signal in SDI can contain up to 16 independent digital audio signals along with the video signal.
Serial digital interface (SDI) is a standard for delivering baseband video and audio over standard cabling. It was the replacement for good ole fashioned professional analog signals. Think old school. It requires 75 ohm coax cable which can be bulky and expensive. A signal in SDI can contain up to 16 independent digital audio signals along with the video signal. It’s robust and has been the choice for moving signals until both proprietary and acknowledged industry specifications for digital arrived.
So, what’s the difference between High-Definition Multimedia Interface (HDMI) and SDI? First, consider that HDMI was designed as a proprietary interface by a consortium of consumer equipment manufacturers for consumer use (that included High-Bandwidth Digital Content Protection (HDCP) copy protection features to make Hollywood happy). HDMI and SDI both support uncompressed video and compressed or uncompressed digital audio, but there is a big difference in installs and associated costs. In most cases, an HDMI cable cannot extend much beyond 50 feet without needing an amp to boost the HDMI signal or converting the signal to SDI and then back to HDMI (very common in daisy-chaining a number of monitors together when separated by large distances). So, although HDMI makes for a great monitor feed, it’s not ideal for those long cable runs from a camera up in the balcony.
What is NDI? | www.newtek.com | www.vizrt.com
NDI 5 allows churches to easily share live, high-quality, low-latency video with anyone else in real time, using billions of devices.
Here is a great description of NDI from the professionals at Newtek/Vizrt: “Network Device Interface (NDI) is a royalty-free software standard developed by NewTek to enable video-compatible products to communicate, deliver, and receive high-definition video over a computer network in a high-quality, low-latency manner that is frame accurate and suitable for switching in a live production.” Version 5 (NDI 5) came out in June 2021, loaded with new features such as NDI Bridge and NDI remote. You can read up on those and other features at https://www.ndi.tv/blog/ndi-5/.
A number of industries use NDI and like its simplicity over SMPTE ST 2110 (more on this later). Additionally, less expensive equipment will have NDI and not SMPTE ST 2110, while more expensive (purely broadcast) equipment will have SMPTE ST 2110 and not NDI. Remember, the right tool for the right job.
In houses of worship, in particular, computer networks often serve many functions, including internet and email connectivity—mission critical items. But on the weekends, video is mission critical too. So having two vital functions sharing a single network could be problematic. Hence the need for managed switches that effectively partition parts of your network for specific purposes, and hence the need for trained people who understand AV and IT.
An important item to note in Vizrt’s definition of NDI is the term “low-latency,” which can be a dangerously relative term. A bit of latency in a live stream or digital signage feed can be perfectly acceptable. Latency in your IMAG feed, though, is distracting and largely unacceptable, and a part of that comes from the monitors and projectors themselves that add latency as they convert the incoming signal to something to be displayed. We’ve all seen it and we all hate it, but it’s a fact we have to live with to a degree: we’re going to have latency. The goal, however, is to keep it as low as possible.
Let’s talk SRT | www.matrox.com
Image courtesy of Haivision.
Here’s a good tech definition of SRT from the team at Matrox: “Secure Reliable Transport (SRT) is a royalty-free, open-source video transport protocol that supports low-latency, high-performance streaming over noisy or unpredictable networks such as the public internet. Matrox is a member of the SRT Alliance that manages and promotes the use of the SRT protocol…
“Many protocols have addressed compatibility distribution of streaming video to a very large volume of viewers who are consuming content from disparate devices and appliances. However, one of the best ways to leverage the assets already on premises at various organizations, as well as the considerable investment by service providers in the cloud, is to feed streaming distribution tools with very low-latency video and do so very reliably. SRT takes some of the best aspects of User Datagram Protocol (UDP), such as low latency, but adds error-checking to match the reliability of Transmission Control Protocol/Internet Protocol (TCP/IP). While TCP/IP handles all data profiles and is optimal for its job, SRT can address high-performance video specifically.”
This all means that SRT promises higher performance with very low latency using an IP computer network.
So what is Dante and Dante AV? | www.audinate.com
Learn more about Dante and Dante AV enabled products at www.audinate.com.
Audinate’s Dante hardware or software in a device takes digital audio and “packetizes” it. The audio is segmented and wrapped in IP packets suitable for transmission across a standard IP network. The packets contain timing information and source and destination network addresses, allowing them to be routed through the network to the correct destination.
When a device receives Dante audio packets, it reconstructs them back into a continuous digital audio stream, which is then played out, recorded, or digitally processed, depending on that device’s role in the audio system. Performance can be impressive: all Dante audio is 100% lossless, 24- or 32-bit, and sample rates from 44.1 kHz to 192 kHz are supported.
Dante AV does the same job with video, taking compressed video signals and converting them into IP packets that share the same timing and control mechanisms as Dante audio.
SMPTE ST 2110 | www.smpte.org
SMPTE ST 2110 is a very promising suite of standards for delivering media over IP networks. It’s designed specifically for high-end, high-capacity environments and it’s complicated. It’s being adopted by broadcast and media organizations to replace SDI to bring the benefits of a virtualized IP-based environment to those industries – although both are digital formats, they are handled very differently. So while it’s a technology to watch for production, storage, and distribution, it’s not likely an option for most houses of worship … yet.
If you want to get ahead of the pack, read up on SMPTE ST 2110 at https://www.smpte.org/smpte-st-2110-faq.
Moving on …
In the church world, many will say that what they have in their venue for signal distribution right now is working, so why change it? While this is understandable, there will likely come a time in the near future when the technology a church has in place right now may not be able to keep up. Video is becoming too important. At some point, tech leaders and their teams will need to rethink what is required to route HD or 4K (or higher) video around their facilities, to and from storage and content management systems and out to online audiences. And the new equipment they will be considering will have some, or maybe all, of the formats noted above. And that will mean starting out with a basic understanding of signal flow in order to set up or reset a video infrastructure. In order to do that, church teams will need to know what questions to ask and they will need to have some basic signal management understanding.
A smart move – reaching out to experts
If you do your research on the subject of signal distribution and reach out to some of the brightest engineering and production people you know, they will likely all say pretty much the same thing: managing signal flow and the potential for upgrading is really all about two things. The first is knowing the signal flow distribution options within the venue, or “on premises” or “on prem” for short. The second is knowing how robust the internet service is in your city or town. This will be a big factor in decision making, especially when it comes to network crunch time.
These same engineers and production pros will also recommend that if you aren’t sure how everything currently goes together in your facility, then you might start by making a simple diagram, on paper, so you can visualize exactly what you have. This will include things like cameras, video switchers, displays and audio, as well as any other gear you have in the pipeline. In addition, this will be a good opportunity to update your equipment list if you haven’t done that in a while. (If you already have all that information on hand, good for you!) And make sure that your administration has a copy for insurance purposes too. Once you have all that information down, then you will be ready when it’s time to figure out your next steps.
Parting thoughts
By now, you may be thinking that video over IP (and AV over IP, at large) is either a pretty cool subject or a huge headache. There is a sizable learning curve for church techs, to be certain. And you will have a lot of questions. So it’s a wise move to seek out and talk to other techs and tech pros in your area. In the end, this legwork will help ensure that whatever solution you choose is the right one for you and your mission. Godspeed!
