Everything you need to know about NDI

NewTek’s Network Device Interface (NDI) was the first IP solution to really take the market by storm. Its productised, modular solutions, wide partner network and open SDK, make it easy to add NDI support to your current workflow. Many see it as an easier and cheaper route to IP-based operation than SMPTE’s slow-moving, costly to implement, standards. Here’s what you need to know before getting set up.

 

Liz Sunter

Firstly, it’s not about NewTek. They developed the platform and give it away for free, so the SDK has made its way into the hands of thousands of developers and customers. At any point in your NDI workflow, you’re able to choose from solutions by a range of vendors, which means an NDI setup is easier to customise than one based on other, more proprietary Video over IP standards: you won’t find yourself shackled to one vendor. No matter who makes a piece of NDI software or hardware they all speak the same language and are all using the same codec.

“The codec is really the jewel in NDI’s crown,” said Mark Gilbert, CTO of software developers Gallery SIENNA, one of the first and most prolific developers of NDI tools. “NewTek have spent years crafting it in machine language, and it’s much faster than anything else out there – with a standard like SMPTE 2110, you need a whole computer to handle one video stream, but NDI is so efficient that encoding each stream takes only a fraction of your computer’s CPU, and it’s an order of magnitude faster than anything else out there.”

So fast, in fact, that NDI claim it can encode 1000 frames of 4K video per second on a single CPU, with that figure jumping to 2500 for HD footage. As well as video data, each NDI stream can carry up to 16 channels of embedded floating point audio and bi-directional data, meaning you can use NDI to control tally lights, PTZ cameras and the like all over one network connection.

Each HD NDI stream has a data rate of up to 100 Mbps, which means one can transmit seven simultaneous streams of NDI video, audio and data using a 1Gbps network connection. This brings us to what is probably the best-known and most-discussed thing about NDI: its compression.

 
The case for compression

While other video over IP standards, such as SMPTE’s 2110 and 2022, make a point of moving uncompressed video around your network, NDI uses the same visually lossless compression that’s at work in ProRes and DNxHD, resulting in a high quality image that’s far easier to move. While this has been held against the standard in some circles, Gilbert insists: “Most people would not be able to see the difference on most material. For the vast majority of what people do, compression is a non-consideration. But it means you can move from SDI to IP for thousands of pounds, instead of hundreds of thousands, with access to a much broader range of functionality and the ability to do much more with the same hardware computing and networking resources.

“For a medium sized facility, moving to an uncompressed IP workflow is a huge upheaval. It’s a massive budgetary obligation, there’s a massive infrastructure requirement for dedicated fibre optic cabling, and then none of your end points work with 2110 anyway, so there’s work to do there. And at the end of the day you’ll see very little change for a lot of money, because you’re just replacing HD SDI 1:1.”

 

Why choose NDI? 
 

Low cost of entry NDI will work on your existing 1Gb network. If you decide that you do want to install a separate network specifically for NDI, you’ll be able to use cost effective, Cat6e cables and standard 1Gb switches, rather than having to upgrade your switches to 10GbE as you will need to in order to adopt standard like 2110. There are a number of free NDI tools from NewTek and developers like Gallery SIENNA which mean you can avoid purchasing expensive production gear, and move toward a more flexible and futureproof software-based workflow.

Bi-directional functionality Because it wasn’t designed to ape SDI, NDI offer several features that are missing from standards that aim to replicate the SDI experience. Tally lights can be controlled the same way. You can run elements of your NDI workflow off phantom power. The end result is a huge reduction in the amount (and cost) of connections needed, and the ability to send far less kit to locations or events you want to capture.

A simpler graphics workflow Fill and key alpha channel information can be sent over the same NDI connection as everything else, meaning fewer connections are needed. What’s more, every single graphics element can be sent as a separate NDI source. For example, a game clock, a live scoreboard and a news ticker could all be parallel, separate NDI sources, as opposed to separate fill and key pairs with all the infrastructure that necessitates.

Capture over WiFi with NDI | HX NewTek have produced a variation on their codec, NDI | HX, which is designed to work with PTZ cameras to deliver a NDI-compatible stream using their native H264 compression. While it results in slightly lower image quality, it does bring PTZ cameras into an ecosystem they’d otherwise be excluded from, which is great for live events and sports coverage, and the data rate is so low that you could conceivably send footage from the arena back to base over WiFi.

Intelligent streaming NDI streams carry a full frame, full resolution version of your footage and a lower resolution proxy version of your footage. This smaller version of your footage is ideal for reducing the load on the network when streaming to multi-viewers, vision mixers or preview screens. If you want to take a given source live, NDI can switch to the full-res version within one frame. It also handles multicasting in a more intelligent way than many other solutions. While many multicasting solutions cast everything just in case someone is listening, NDI only sends data to endpoints when it knows someone is listening, reducing the load on your network and CPU.

More than just a broadcast standard “NDI’s flexibility extends its usefulness beyond the broadcast space and into AV applications,” said Corcoran. “You can deliver content to third screens and mobile phones because it doesn’t care about screen geometry, and as of version 3.0 it has support for multicasting, which is a popular delivery method for large scale corporate comms. It’ll even work with the standard controllers in most presentation environments.”

Gradual, manageable migration It’s hard to move from SDI to a standard like 2110 piecemeal, but switching everything over at once is too expensive for many companies to contemplate. With NDI, you can switch over gradually, using low cost converters to move SDI signals onto your NDI network for easy routing round your studio or facility, then reconverting them back to SDI when they encounter an SDI endpoint (the monitor in a grading suite, for example). Then, you can replace your SDI inputs and endpoints with native NDI ones as and when the budget becomes available.

Broad vendor support base NDI is supported by more developers and vendors than any other standard. Notable names include: Vizrt graphics and production systems; Panasonic’s range of PTZ cameras; Adobe and Avid NLEs; Birddog converters, and Telestream, Teradek and Softron solutions.

Ready-made ‘glue rack’ tools Developers are producing tools for very specific tasks, like audio de-embedding and frame rate conversion, that allow you to replace traditional hardware stacks with NDI solutions without losing any of this vital functionality. Mark Gilbert, from Gallery says;

“Most of our customers have an entire rack of sound synchronisers, aspect ratio convertors, audio embedders and de-embedders – all those little boxes and cards that allow you to build a broadcast facility or a production facility. These things don’t exist in the 2110 world, but our NDI Process Engine functions like a virtual glue rack, allowing you to carry out all these process that we’ve all come to depend on.”

 

The day one experience

Getting started with NDI is simpler than most people imagine. A lot of the basic tools are free, and setup can take minutes. “NDI is designed to deliver a good ‘day one’ experience,’ said Gilbert.

You can download free apps and run them on your existing network, and you’ll be doing NDI within ten minutes. There are loads of free tools that run on your existing computers, network and switch, and move high quality video from one computer to another. You then start to discover that there’s a massive array of software and hardware from different vendors that supports NDI, and they’re all 100% compatible. And it gives you this enormously broad toolkit to start building on.”

 

We recommend...

Birddog Encoder One of our favourite camcorder encoders, Birddog’s effort delivers dual colour tally and power over Ethernet at the same time as encoding your camera’s output to NDI. Decoders also available in case you need to monitor SDI at the other end, and BirdDog have just announced their own range of NDI PTZ cameras at IBC

NDI Router As well as basic tools like SDI converters, scan converters and NDI monitoring solutions, Gallery SIENNA have developed a number of applications that make it easy for end users to handle the transition to NDI. NDI Router, for example, simulates the experience of defining inputs and outputs in an SDI router, even though these things are decided at the endpoint in an NDI workflow. All this means that users with experience of SDI workflows don’t need to retrain for NDI. You can find out more about Gallery SIENNA’s products here.

SIENNA Cloud for NDI Got production facilities in several locations? SIENNA Cloud extends NDI functionality from your LAN to your WAN, and means that any user in any facility can see any NDI inputs on the WAN as if they were local. For example, if a London facility were bringing in NDI feeds from cameras at Wimbledon, editors at different branches around the world would be able to see, mix and edit from those sources to create different packages for their regions.

Panasonic’s NDI|HX PTZ cameras Panasonic were instrumental in developing the NDI|HX codec, and a number of the PTZ range already support the standard. The AW-HN130, AW-UN70, AW-HN40 and AW-HN38 can stream 1080p full HD footage at just 15Mbps. And for ease of use, your NDI system will automatically detect NDI|HX-capable cameras, making seamless integration with TriCasters, NewTek IP switchers, and any number of the NDI software plug-ins products available. If you’d like a non-NewTek control panel, it’s also worth taking a look at their AV-HLC100.

Softron MovieRecorder This multicam edit-while-ingest tool for Mac can handle up to 16 channels on one computer, and offers support for NDI, external audio sources, effects and overlays and HEVC (H.265). Download a demo version here.

Telestream Wirecast Telestream’s established solution for streaming has already added NDI to its long list of supported inputs and outputs, meaning if you have the latest version, you can multicast and unicast over your LAN via NDI without any real change to your Wirecast workflow.

Wowza Media Distribution System This MDS is fully equipped for existing and emerging SDI, IP, and hybrid workflows, with flawless, multi-format processing allowing supported source types to be used interchangeably on each channel. Streaming signals are acquired through direct, physical input using 3G/HD/SD-SDI hardware connections, over IP via NDI, NewTek’s innovative Network Device Interface technology, and from other sources, including TCP/IP, webcams, and USB capture devices.

 

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