NDI Vs SDI, What Are Their Differences?

NDI (Network Device Interface) and SDI (Serial digital interface) are industry standards that are used for transmitting uncompressed video over Ethernet. These technologies enable efficient acquisition, distribution, and cabling of video signals within a facility or across an IP network. 

 

Delimiter will now share a detailed comparison between NDI and SDI in order to help readers understand the technical details of these standards.

 

With these reasons, let’s find out the difference between NDI and SDI. 

What is NDI?

SDI ptz camera 1
Source: Telycam

NDI stands for Network Device Interface, which is a protocol that enables applications to discover and interact with network devices. It’s an open source protocol that has been developed by NewTek and can be used across multiple platforms.

NDI is a low-latency, high-performance transport layer designed for real-time applications such as audio/video streaming, digital signage, collaboration and remote desktop. It has been designed to be agnostic to the underlying transport layer (e.g. UDP), making it ideal for use over any type of network connection including WiFi and cellular networks.

Video sources include video capture cards, graphics-processing units (GPUs), webcams, and streaming servers. Video sinks include video display devices (such as projectors, monitors and TV screens), recording devices (such as cameras) and streaming clients (such as mobile devices).

NDI is a complete and open standard that allows any vendor to develop NDI compatible products without having to pay royalty or license fees.

What is SDI?

SDI Signals
Source: unsplash

Serial Digital Interface (SDI) is a serial digital data protocol and video transmission standard used in professional video applications. SDI is a standardized version of the Electronic Industries Alliance (EIA) RS-170A, which was created for analog video. SDI is also used in consumer applications such as high definition television (HDTV) and high definition serial digital interface (HDSDI).

 

The SDI standard defines the physical layer, including the electrical interface, signal levels, and other considerations for use in professional video equipment. The SDI standard specifies bit rates from 270 Mbit/s to 1250 Mbit/s. SDI can be transported over either coaxial cable or fiber optic cable, commonly called “light pipe.” The choice between coaxial cable or fiber optic cable depends on the length of the cable and whether it will be installed as part of an outside plant (OSP) or an inside plant (IP).

 

A single-link SDI signal can be transported over three types of cables: Type A, Type B and Type C.

What are differences between NDI and SDI?

NDI and SDI are standards used to transport video across a network. They both support HD and Ultra HD formats, but they differ in how they handle resolution and frame rate.


NDI is a packet-based protocol that uses UDP/IP as its transport mechanism. It supports resolutions up to 4K NDI camera and allows for real-time streaming of uncompressed video over the network. NDI can also compress video on the fly before sending it over the network (this feature is known as NDI Studio).

NDI Pros

NDI is a protocol for sending video and audio from one device to another. It was created by the Video Services Forum (VSF), a non-profit organization that aims to standardize the way in which video is transmitted over IP networks.

 

Because NDI is an open protocol, it can be used by any application or hardware manufacturer for free. This means that NDI devices can communicate with each other, regardless of their manufacturer and software.

 

The advantages of using NDI include:

NDI Cons

There are a few disadvantages to using NDI. 

The first is that it's not as widely available as other streaming technologies, such as RTMP and RTSP. Many devices don't support NDI, and some that do may not work with your system or application.

The second disadvantage is that there are no standards yet for how to create an NDI stream. That means that if you want to broadcast to multiple devices at once, you'll need to set up individual streams to each device. You can also create multiple streams per device and send them out at different resolutions (for example, 720p and 1080p).

Another disadvantage of using NDI is that the protocol isn't always reliable. Sometimes there are network issues or problems with your hardware (such as faulty drivers) that cause NDI streams to drop out or be delayed by several seconds when they get going again.

NDI Attributes

The NDI protocol is optimized for low latency, high performance video and audio streaming. It is also designed to be flexible and extensible.

 

Here are some of the key attributes:

Low latency – NDI is designed to be as low latency as possible, so it can be used in live production environments where feedback from a user or control input needs to be reflected on screen immediately.

High performance – NDI uses UDP (User Datagram Protocol) multicast packets which allows NDI devices to transmit data with minimal overhead. This means that NDI can support very large numbers of connected devices without impacting network bandwidth or CPU usage at the source device.

Flexible – The architecture of NDI allows developers to create custom device drivers that can be added into the ecosystem using an open source SDK. This makes it easy for developers to integrate their existing products into an ecosystem where all the devices work together seamlessly.

Extensible – The architecture of NDI allows developers to create custom extensions without having to modify any core code in the base library.

SDI is a bit-encoded protocol that uses SDI cables for transport. It supports resolutions up to 2K ptz sdi , which means that it’s not as good for high-resolution applications as NDI. However, SDI is more reliable than UDP/IP because it has been around longer and has been optimized for audio/video transport over long distances.

SDI Pros

SDI could be used in various devices to improve their performance and productivity. It can be used to run applications across multiple devices, including Television, laptops, smartphones and tablets.

The following are some of the pros of using SDI:

Lossless: SDI signal stands for Serial Digital Interface. SDI is an uncompressed signal, with lossless image quality, stable transmission and high reliability;

Real-time: The signal transmission delay rate is very low, there is almost no image delay, and the live broadcast effect is very good; the quality of video is broadcast grade.

Ease of use: An SDI cable only transmits one signal, and the logical relationship between the signal and the cable is clear, no settings are required, and it is easy to locate and troubleshoot.

Compatible with most video sources

Camera Link, USB3 Vision and others all require a computer in between the camera and the monitor. Howerever, direct connection between the camera and the display could be achieved by using SDI.

True plug and play solution is possible with SDI. That is why it could be used to live streaming and create monitor system.

SDI Cons

There are a number of cons to using SDI, such as:

The transmission distance of SDI cables is limited: one line and one signal lead to too many cables, and there will be hundreds or even thousands of SDI cables in the broadcast equipment room of the TV station, which increases the difficulty of wiring and maintenance. In the event of a failure, the solution is usually to add a new line instead of replacing the failed cable;

The resolution and frame speeds must be preset (lose flexibility);

There is no problem with the transmission of high-definition digital TV signals through SDI cables, but it is difficult to transmit ultra-high-definition TV signals. Four 3G-SDI cables are required to transmit a 4K ultra-high-definition signal, and the requirements for the device interface are too high; although a single 12G-SDI cable has appeared, the high price makes it far away from entering the practical stage, and it is not compatible with IP Compared with transmission, there is no advantage. Therefore, to develop 4K ultra-high-definition digital TV, we can only abandon the SDI architecture;

The cost of SDI cables and corresponding processing equipment is high. Now the signal source and output have increased, the scale of SDI scheduling signals has continued to expand, and the cost of system implementation has also increased significantly. Moreover, It is a purpose specific interface, which requires more cost especially for 4K SDI.

There is no monochrome because the standard is designed for color cameras (but now there are some solutions)

SDI Attributes

Serial digital interface (SDI) is a family of digital video interfaces first standardized by SMPTE. SDI consists of consists of 3G-SDI, 6G-SDI and 12G-SDI and so more. SDI and HD SDI are commonly used in professional video equipements like PTZ living streaming camera. The quality of image is uncompressed during the transmission, and could connect different pieces of devices like monitors, PCs and vision mixers, recorders. Moreover, the distance of video transmission is typically less than 300 meters, but shorter lengths are preferred. The HD bitrates have a shorter maximum run length, typically 100 meters (330 ft).

Which one is better to for PTZ camera: NDI vs SDI?

ptz camera for education
Source: Unsplash

Both SDI and NDI will aid us in producing high-quality picture and outstanding audio as 2022 ushers us into the future of video communication. Since the 1980s, SDI has been the digital video standard, but NDI is gaining momentum as the best network link for broadcasting video communications.

 

With quicker, higher-quality images up to 4K and superior audio quality, NDI is the better choice for 2022. SDI cameras have been pushed out due to their lack of mobility and lack of PoE capability due to NDI’s ability to completely optimize interface controllers, mixers, and PTZ cameras. In general, NDI is the digital interface of the future for streaming and video communication.

Where to get NDI PTZ camera?

NDI PTZ cameras are getting popular in the market, and they are increasingly used in many fields.

 

The most important feature of an NDI PTZ camera is its high resolution. In addition to the high resolution, it also has a wide viewing angle, which can meet your needs very well.

 

The question is, where can we purchase one? Although there are lots of PTZ camera factory or webcam suppliers today, choosing the most trusted one is  a must. You can either buy it through a physical store or online. However, the most convenient one is through online since you’ll just swipe out from your phone or pc in taking your orders.

 

Start your purchasing at: Telycam (Telecam Technology Co.,Ltd) is a specialized manufacturer of PTZ Cameras for video conferencing and live streaming. Telycam, which has been involved in the audiovisual business since 2014, combines the benefits of a solid supply chain, well-organized production, significant R&D capabilities, and expert services in order to provide the finest audiovisual solutions to our consumers. They have established their name  because of their Telycam webcam & PTZ.


Telycam has grown at a quick pace since its inception in 2014. Throughout the years, we have insisted on innovation and have achieved little successes. We are known for webcam & ptz camera company Telycam, and will continue to raise our brand globally.

Other questions

What is the difference between NDI and NDI HX?

NDI Camera Discovery
Source: Google

NDI is a protocol created by NewTek to allow the connection of all video sources to almost any other video source.

NDI HX is a newer version of NDI, which introduces some improvements over the original version. It’s primarily used for high-resolution applications such as 4K and 8K. It can also be used as ptz live stream camera.

The main difference between NDI and NDI HX is that, while both can be used to send video over Ethernet ( ndi ptz camera) , NDI HX supports higher resolutions than NDI. Specifically, it can send 4K, 5K, 6K and 8K video at up to 60 frames per second (fps). On the other hand, NDI supports only 720p resolution at 30 fps and 1080p resolution at 60 fps.

NDI HX also supports more audio codecs than NDI — AAC-LC, Dolby E and PCM — while NDI only supports AAC-LC audio compression format.

Conclusion

The SDI standard is supported by a multitude of equipment manufacturers, most mainstream content creators, and most transmission infrastructure providers. 

 

However, NDI is a promising young contender that has been gaining much attention in the industry. It supports capabilities that SDI does not, and its advanced networking features may provide the killer edge that it needs to really take off.


Choosing a reputable PTZ manufacturer, like Telycam, is key. Contact them immediately if you want to have a standard ptz camera!

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