Network Device Interface
Broadcasters rely on their cameras and computers to capture, edit, and transmit live video feeds. And most modern broadcasts rely on video feeds from more than one camera to create a seamless experience that shows the audience every angle.
The Network Device Interface (NDI®) protocol is the technology that allows all of those individual devices to connect. And without that connection, devices wouldn't be able to send and receive multiple signals. But thanks to NDI, audiences can use their home computers or even a smartphone to watch a live sports broadcast, attend a virtual learning event, or join a web conference.
What Is a Network Device Interface?
NDI® is an internet video transmission protocol that dictates how multiple devices connect and share large amounts of data with minimal lag. To put it more simply, NDI is the standard that allows for high-quality live streams that rely on more than one source of video and audio.
For instance, the NFL uses multiple camera sources to capture every angle of the field, along with shots of players and coaches on the sidelines. NDI is what allows the league to utilize them all in its broadcast to create a seamless experience.
Software company NewTek first announced the NDI protocol in 2015. And in 2016, NewTek made NDI publicly available and began offering a royalty-free download of the protocol and its accompanying software development kit (SDK).
Before the introduction of NDI, the best options for transmitting high-quality video were HDMI or SDI. These video transmission methods rely on physical cabling, which comes with limitations. Neither HDMI nor SDI compresses data, which means they can only send as much data as the cable can handle. And if the cable doesn't have enough bandwidth, broadcasting video will be like trying to put out a house fire with a garden hose — slow, and not enough data will come through to make a noticeable difference.
Without NDI, even something as simple as presenting a video can be a challenge, especially when you run into problems like short cabling. For instance, a public speaker won't be able to connect their personal computer to a projector without the proper length of cabling. But if the cable is too long, it could easily tangle itself or become a tripping hazard. But thanks to NDI, public speakers can use Wi-Fi to screencast presentations, eliminating the need to find an HDMI cable altogether.
How Does a Network Device Interface Work?
NDI is a capability that's built into devices themselves, including cameras, computers, and smartphones, as well as web-based applications like Zoom. It relies on a device's existing network infrastructure to share video rather than using physical cabling to connect devices.
Engineers build NDI directly into devices and apps themselves, which enables devices to connect and share data by compressing and encoding it. And other NDI devices on the same network can automatically access and decode the data.
There are two types of NDI connections that engineers can integrate into development:
Wired NDI: This type of NDI relies on a device's wired ethernet connection to transmit data between devices. While devices don't need to be connected to each other by cables, they do need their own physical connection to the internet. Wired NDI is often faster than wireless, but the need to connect physically with an ethernet cable means devices are tied to a single location.
Wireless NDI: When NDI devices are connected through a wide-area network (WAN) — what we commonly refer to as Wi-Fi — it's often referred to as "wireless NDI." While this requires a strong internet connection over Wi-Fi, a wireless connection offers greater flexibility without sacrificing high-quality video.
All developers need to do is download the appropriate SDK from NewTek to incorporate NDI into their app or device development. The standard SDK is the more basic of the two and is designed only for NDI application development. Meanwhile, the advanced kit includes additional resources for NDI hardware development. Both kits are free to download and include the key resources and tools developers need to create NDI applications, including:
- NDI encoding algorithm
- IP commands
- UDP transmission protocol
Once the protocol is built into a system, NDI works almost automatically. In most cases, all users need to do is enable NDI in a device's settings. Take Skype as an example. Users navigate to advanced settings where they can allow NDI usage within the app. After making this simple in-app adjustment, content creators can record and livestream calls. Then, Skype uses the camera and microphone on each meeting attendee's computer to capture video and audio before connecting to the computer's local network and transmitting the data.
NewTek regularly releases new versions of its SDK to enhance what it offers engineers and developers. Each updated release includes new capabilities, features, and tools, all of which are designed to improve media production. The most recent version, NDI 5.5, was released in August 2022 and includes a new router as well as an advanced audio input/output.
While NewTek's website notes that they are subject to change, the current minimum system requirements to use the NDI 5.5 SDK include:
- 8 GB system memory
- Processor: CPU, GPU
- Operating system: Windows 7
- Minimum screen resolution: 1024 x 768
- Network: Gigabit internet
3 Benefits of Using Network Device Interface
The primary benefit of NDI is the ability to simultaneously transmit and receive multiple video inputs through Wi-Fi. This makes it easy to upload, edit, and broadcast professional videos in real time. However, you will also:
1. Save Money
NDI is widely compatible with popular broadcasting equipment and software, so you won't need to buy additional tools to connect devices or transmit video. In fact, NewTek offers a variety of free tools that enhance NDI video, including a virtual remote and integrations for Adobe Creative Suite.
However, if you don't already own a modern ethernet cable for wired NDI, you still may need to purchase a high-bandwidth cable for a fast and reliable NDI connection. So technically, NDI might require you to buy one additional tool.
But NDI's alternatives often require additional equipment beyond cabling to effectively connect devices and broadcast video. In addition to either HDMI or SDI cabling that's compatible with your chosen device, you may need to invest in:
- Extenders, to stretch the reach of your existing cabling
- Encoders, which compress and convert data packages for different purposes
- HDMI matrix switcher, to route and centralize all device inputs and outputs
2. Simplify Streaming
In some cases, individual cameras capturing and transmitting video may each have their own human operator. But thanks to NDI, that doesn't always have to be the case. The built-in protocol includes both encoding and decoding algorithms, which means all NDI devices can both send and receive signals.
This two-way communication allows you to control multiple devices from a single location — as long as they're all on the same network. For instance, a computer in the control room can issue commands to individual cameras, instructing each one to point, tilt, or zoom.
3. Improve Low-Latency Broadcast Quality
NDI uses compression to shrink video data packages before transmission. This means it requires less bandwidth to transmit a professional, high-quality broadcast. And other NDI devices that tune in to the broadcast can easily decode the data in real time, creating a frame-accurate and "visually lossless" experience for the audience.
Because NDI allows multiple sources to transmit simultaneously, it also gives you the ability to choose the best video angle for the story. The ability to control individual devices lets you pivot to get the best angle or zoom in for a closer look. Since NDI tools allow you to edit each video feed in real time, you can make adjustments to balance colors, boost brightness, or correct for shakiness. And you can do it all even with limited bandwidth, thanks to your device's built-in NDI.
5 Everyday Uses for NDI Video
NDI has become so widespread that it is now the standard, which means you encounter examples of it more often than you might think.
1. Live Event Broadcasts
It takes multiple cameras to get all of the different angles of a football field, basketball court, or hockey rink. NDI allows all of those cameras to connect and upload to a single control room, where editors choose which feed viewers see on their broadcast at home. And with the right NDI devices and tools, broadcasters can even enhance and improve the video audiences see.
For example, Australia's Collingwood Football Club relies on NDI cameras to capture high-quality video of each moment of the game. The team in the control room can then edit the footage to create highlight reels and instant replays that make the game even more exciting for fans at home. By using NDI, the Collingwood team is able to get the clips it needs in as little as 10 seconds.
But the benefits of NDI aren't exclusive to sports broadcasts. They also apply to other live-streamed events that involve multiple video and audio sources. For instance, Sir Elton John's recent performance at Dodger Stadium used 23 cameras, drones, and helicopters to film the event — NDI was what allowed all of the sources to connect so Disney could broadcast the iconic musician's final performance
Just like live sports, esports involves more than one video source that allows the audience to watch multiple players. But unlike an NFL broadcast that uses multiple cameras, an esports tournament also relies on each gamer's computer or gaming device. And NDI can broadcast a live feed of their screens as they compete.
Even outside of official tournaments, streamers like the two friends (Frankie and Booker) who created Rift Watch Gaming TV (RWGTV) rely on NDI video to share video content with their audience. Even though Frankie and Booker live more than 4,000 miles apart, they can both stream a live feed of their own gameplay simultaneously. And each video feed goes to the same channel where their audience can tune in to watch them interact with each other both in the game and on the live stream.
3. Web Conferencing
NDI video also has corporate applications. Businesses can use it to livestream company events as well as broadcast informational meetings with platforms like Zoom. Just take a look at Shopify. As a hybrid company with offices and remote workers around the world, NDI is crucial for keeping teams connected.
Each week, Shopify hosts a livestream for all of its employees. Even though the ecommerce company's broadcast team is based in Ottawa, Canada, employees all around the world can join in the event.
4. Online Learning
Institutions turned to NDI en masse in 2020 when the COVID-19 pandemic shifted schools and colleges to online learning. And many of them continue to rely on NDI to connect students and keep them engaged, even now that they are back on campus. Just take a look at how educational institutions are using NDI to enhance virtual learning for their students.
The University of Wisconsin-Parkside began using auto-tracking NDI cameras and was able to livestream 30 classes in a single semester. The cameras operated independently from the professors, tracking them as they moved through the classrooms, which meant lessons still felt lively and engaging despite moving to an online livestream.
Meanwhile, Fort Hays State University uses the two-way communication capabilities of NDI devices to connect students and their professors. By scheduling virtual meetings, students have an opportunity to meet with their instructors virtually. The connection provided by NDI allows students to have productive conversations with educators who can offer feedback and ask questions in real time.
5. Virtual Fitness Classes
Companies like Peloton are taking advantage of NDI video to broadcast live classes directly to the NDI-equipped home workout equipment they sell to customers. For instance, Peloton bikes come with built-in screens that connect to Peloton's New York studio.
The built-in video monitor allows users to join any of the daily live spin class broadcasts without purchasing any additional display equipment. And because Peloton's customers can view the broadcast directly from their bike's monitor, it's easier for them to stay focused and engaged in each workout.
Frequently Asked Questions
What is the NDI protocol?
NDI® is an internet transmission standard created by NewTek that allows devices to share high-quality, low-latency video in real time by connecting through shared networks like LAN and WAN. To use the protocol, developers download one of two NDI SDKs, which include tools and resources to build NDI capability directly into devices and web applications themselves. And once NDI is built into a device, users simply need to enable it in the device’s settings in order to connect with other NDI devices and livestream video.
What is OBS NDI?
Software designer Stéphane Lepin — sometimes referred to by his GitHub username: Palakis — created the NDI plugin for the popular open-source video streaming platform Open Broadcaster Software Studio (OBS Studio). The streaming platform was launched in 2012 and doesn't have its own built-in NDI. As a result, the OBS system isn't able to communicate with NDI devices without an additional integration.
Since NDI is the new standard for internet video streaming, the plugin is essential for the many OBS users, many of whom rely on NDI devices. Once users implement the OBS NDI plugin, they can:
- Add NDI devices as sources within the OBS platform
- Transmit signals to other NDI devices and systems, like Twitch
- Integrate other NDI tools to better-edit video in OBS
Palakis' OBS NDI integration is available to download for free on GitHub.
What is NDI HX?
NDI HX is an updated version of the NDI protocol that compresses data into smaller packages and does not require gigabit internet. However, while NDI HX can support multiple signals with reduced bandwidth, those streams may be slightly delayed compared with a standard NDI transmission — exactly how long the delay is will depend on the device and the internet connection.
Is NDI better than SDI?
NDI offers greater flexibility for high-quality, low-latency video streaming than the SDI protocol, which makes it a better option for broadcasting video. And while both SDI and HDMI were widely popular video transmission standards less than a decade ago, since the 2015 introduction of NDI, they have become less common.
SDI (as well as HDMI) relies on physical cabling to connect and transmit video and audio signals between devices. And the more devices, the more cabling you need. SDI also presents other problems, such as:
- The number of connections a device can make depends on how many SDI ports it has
- Reliance on physical connections means you’ll need to buy additional tools, including cables, adapters, routers, and transmitters
- Cable length dictates how far devices can be from each other before connection becomes impossible
Using NDI helps you avoid these problems by using ethernet or Wi-Fi rather than cabling to connect devices and transmit video in real time. Because it’s built into devices, it’s also user-friendly and requires little experience to start live streaming.
Is NDI better than SRT?
Both the NDI and Secure Reliable Transport (SRT) protocols enable low-latency, high-quality video streaming. But unlike NDI, the SRT protocol supports end-to-end encryption. While NDI will work well on its own for most common uses, professional broadcasters and others that need more security should combine it with SRT.