Who needs SDI? Your guide to IP workflows

Between NewTek’s NDI product suite, Audinate’s Dante solutions and SMPTE 2110, there’s a lot of scope for moving away from SDI in favour of an IP workflow. But who are IP workflows really right for now? When is the right time for you change your set-up? And how is this going to affect your workflow and your network bandwidth needs? Here’s what you need to know before jumping on the bandwagon.   


Liz Sunter

There are some fairly obvious benefits to moving to an IP workflow if you’re updating your facility or building a new one. CAT6 cables cost about a sixth of what HD-SDI ones do per metre, and you may be able to use some of your existing cabling. You can use cheap, off the shelf hardware to route signals, cutting costs further. If you’re using a virtualised workflow using virtual sound cards, interfaces etc, working over IP allows you to connect directly to a CPU without the need for any external devices and controllers. The amount of cabling it lets you cut out of an OB truck allows you to cut the weight of one by half.   

However, SDI is still very good at what it does, and whether it’s in your best interests to move to an IP workflow now depends on what you want to do, what equipment you want to do it on, and which standard you want to use.     


Let’s start with the standards 

There are a few competing ones, but the three you’ll most readily encounter are:  

SMPTE 2022: The first SMPTE standard for video over IP, which delivers a combined audio and video signal that basically acts like an SDI signal, but is delivered over IP. If you’re working with audio, you’ll need to get familiar with PTP syncing in order to meet the strict synchronicity requirements of 2022. 

SMPTE 2110: A more recent standard for audio and video over IP. Notable for sending video and audio as separate data streams rather than embedding the audio; useful in mixed media facilities as it means you can pull an audio feed (for monitoring, say) without having to de-embed and re-embed the video. Is supported by AES67 compatible audio streams (i.e. Ravenna, Dante running in AES67 mode, etc…)

NewTek NDI: An IP solution developed by Newtek, but which they’ve opened up for all, so there are now huge numbers of hardware and software developers creating creative, useful and essential components, that really consolidate this open standard. Primarily focused on working within a single LAN, it is the only standard that is completely resolution, frame rate and SDR/HDR agnostic, and will run on off-the-shelf IT hardware. It’s a remarkably efficient wavelet codec, along the lines of DnXHD or ProRes.


Which is right for you?  

As mentioned before, NDI is designed primarily for video use, specifically to move video signals around a single facility. We’re seeing it used heavily to connect cameras, vision mixers, displays and other inputs in studios run by our corporate, HE and sports clients, as it offers a cost-effective way to implement a broadcast workflow with limited budget and no television delivery obligations. (That it integrates seamlessly with NewTek’s TriCaster mixing and streaming solutions, and can deliver any resolution or shape of footage, rather than just your traditional 1920x1080, doesn’t hurt if you’re primarily delivering footage to mobile devices of every shape and size.)  

NewTek promise NDI can deliver multiple streams of HD video over a CAT5e network and 1GB switches – a typical NDI steam takes up about 100Mbs of bandwidth. Adding 10GbE switches or CAT6 networking can improve your stream count considerably, as can choosing cameras that support NDI|HX, a new codec NewTek recently pushed out as a firmware update, which can reduce the bandwidth needed per stream of HD to as little as 10Mbps.   

We’ve seen our customers in larger facilities take advantage of this by replacing expensive routers with an NDI solution – video is sent from a central machine room over the network to individual edit suites, where a NewTek NC1 convertor is used to turn that signal back into a baseband signal that can be read by editors’ monitors.   

There are two main things to be aware of when using NDI: as stated above, it’s not very precise about its timing (a frame sync is used to ensure video and audio are delivered at the same time, but it doesn’t insist that every device on the network be clocked, or that endpoints be synchronised. This is good because it means a lot less setup and configuration is needed to get NDI systems off the ground – the main response you’ll get if you ask around is that NDI ‘just works’ – but that comes at the expense of it being suitable for high end audio work.   

The other thing to bear in mind is that video delivered over NDI is compressed. It’s wavelet compression, which NewTek have been keen to point out is the same kind ProRes uses, and its 150 Mbps data rate is fairly typical in editing environments, but if you need to move an uncompressed video signal around your facility, NDI isn’t the option for you. In fact, in both cases, you’re going to need to turn the SMPTE-sanctioned options: 2110 and 2022.   


The SMPTE options 

SMPTE standards 2110 and 2022 may differ in how they handle audio, but they’re sufficiently cooperative that they will coexist on the same network, meaning a mixed installation is fine as long as you have a vision mixer which also understands everything.    

Both standards deliver uncompressed video and AES67-compitible audio, though 2022 delivers the two as a single data stream, while 2110 delivers the two in separate, but strictly synchronised streams. As the video stream is uncompressed, working over SMPTE standards requires more expensive 10GbE cabling and switches, especially if you’re working with higher resolution videos.   

However, if cost is not your overriding concern, using the SMPTE standards can have several advantages. Kitting out an OB van in this way, rather than using SDI, will cut its weight by about half. Extracting, changing and re-inserting an audio stream is far easier over 2110 than any other available standard, and the audio industry’s broad adoption of Dante and Ravenna technology means that there is a full range of compatible hardware and software solutions available for anyone wanting to work with audio over IP.    

In fact, audio facilities who want to reduce costs without sacrificing precision have been using the AoIP standards to drive their workflows for years now, and if you’re upgrading a space where you work solely on audio projects, it’s well worth looking into how much of your workflow you could complete over IP.

Considering core hardware A key factor when choosing between standards – and especially between the two SMPTE options – is which key hardware you have to support, particularly in the audio space, and the two standards handle audio slightly differently.    

Ravenna hardware works natively with 2110 and Dante endpoints will need to be operating in AES67-compatibly mode to work natively, although both audio protocols can be integrated with both standards with appropriate hardware. However, if there is a key piece of hardware at the core of your studio workflow, testing this with each protocol and leading with the workflow that is most suited to that particular piece of kit is the best way to ensure you get the most out of your updated network – if you still can’t decide, bear in mind that Dante’s reach and product range make it the more futureproof of the two.

NewTek have opened the NDI standard to developers and manufacturers for free, meaning that the range compatible hardware and software is large, and constantly expanding. While NewTek only issue Windows-compatible versions of many of the key software tools, third parties such as Sienna have been hard at work developing macOS-compatible versions, so you can now use NDI solutions as part of a Mac or PC workflow with more or less the same result.    

When planning your NDI workflow, you do need to bear in mind that it’s a compressed format, designed to move video signals around a single facility, rather than sit as part of a delivery pipeline. While it’ll be fine for almost 100% of your internal monitoring, you will need to give some thought to how you will convert that signal should it need to become part of your broadcast chain.    


So, is it time for you to leave SDI? 

Ultimately, it depends on the complexity of the material you want to move, and the complexity of the workflow you’re moving it within. For simple routing round facilities, or for very local broadcasts (such as campus or stadium networks), NDI is an ideal, low-cost way to move video in a variety of shapes and sizes without any particularly damaging compression.   

For audio-only workflows, there are a wealth of solutions on the market, and uptake among existing facilities is pretty high, meaning most of the available solutions are fairly futureproof and investing in IP workflows is low risk, if you are upgrading or moving studios and want to make the switch.   

For video workflows, or facilities that handle audio and video, things are slightly more complicated. SDI is currently still the best way to handle uncompressed, high res video, but in situations where your initial outlay makes you a long term saving – kitting out IP trucks, or any situation where building constraints make it difficult and expensive to run new video cabling – IP workflows could be right for you. Similarly, if you want to develop studios with a degree of future-proofing, it would be wise to consider making provisions for an IP workflow. The key thing is not to assume that any given solution will simply work off the shelf (though NDI comes close). If you’re considering the move to IP, get in touch with our consultants on the details below to find out how they can help you, and for any advice on how IP solutions can be adapted to suit your particular workflow.     


If you want to know more, give us a call on 03332 409 306 or email broadcast@Jigsaw24.com. For all the latest news, follow @WeAreJigsaw24 on Twitter, or ‘Like’ us on Facebook.


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