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Thursday, 11 August 2022 07:04

Network Device Interface - Beginners Guide

sdi vs ndi sdi vs ndi https://www.pexels.com/photo/cables-connected-on-server-2881229/

Network Device Interface (NDI) is a royalty-free software specification that NewTek developed. Its purpose is to allow video-compatible products to interact, deliver, and obtain better video over a computer network.

All this in a manner that is high-quality, low-latency, frame-accurate, and suitable for switching in a live production environment. Many major firms like medical molding company are now utilizing this technology for video streaming. 

NDI was named "Network Device Interface" because of its ability to communicate, deliver, and receive high-definition video. NDI enables multiple video systems to recognize and communicate with one another over IP. It enables these systems to encrypt, transmit, and receive multiple streams of high-quality, low-latency, and frame-accurate video and audio in real-time.

This new protocol can benefit from graphics systems, capture cards, Video mixers,  and many other production devices.

NDI's Technical Science

It is expected that the NDI codec will be able to deliver 1080i HD video at VBR data rates of around 100 Mbit/s over gigabit Ethernet.

Two other discovery modes are available (NDI Access and NDI Discovery Server), which allow NDI receiving devices to automatically discover and offer these sources. This can happen even when they are not connected to the local area network via the mDNS (Bonjour / Zeroconf) discovery mechanism. The NDI send host provides a list of available TCP ports from which to choose when creating new sources.

In order to establish a TCP connection with the NDI sender, a request for a source is sent to the appropriate port on the NDI sender. 

NDI 3.x has the capability to load balance streams across multiple network interface controllers (NICs) without the utilization of link aggregation. Also, it has the option to use UDP multicast or unicast with the forward error correction (FEC) in place of TCP. With the release of NDI 4.0, multi-TCP connections are now possible.

Multichannel, uncompressed audio, and metadata are all carried by NDI. The sender and receiver can exchange XML-formatted metadata messages over the connection, allowing them to communicate with each other.

With this type of directional metadata system, features such as active tally information can be sent back to the sources, letting them know when they are airing (program/preview). When no NDI receiver clients are connected, senders can avoid wasting network bandwidth and processing by using NDI to count the number of receivers connected.

NDI Receivers can connect to various stream combinations, including audio-only and metadata-only connections if the video recorded in the best led strip light ideas isn't needed in the connection.

Equipment Supported By The NDI 

The Network Device Interface (NDI) is supported by various companies that produce hardware and software. Video mixers, graphics systems, capture cards, and a slew of other production tools support NDI because it benefits any network-connected video device and software. 

Some of the most important are as follows:

  • NewTek
  • Creative Cloud / Adobe
  • JVC's top-tier professional division
  • Panasonic
  • Evertz
  • LiveU
  • Deltacast
  • NewBlue

Examples Of NDI Compression 

As opposed to an uncompressed version of the same format, NDI video streams are distributed over the network at a 15:1 ratio. NewTek's "Adding NDI to your network" documentation estimates how much bandwidth each NDI video stream consumes.

  • A single stream of SD video consumes 20 Mbps of bandwidth.
  • A single stream of 1080p50/59.94 video consumes 125Mbps
  • A single stream of 720p50/59.94 video consumes 90Mbps
  • A single stream of UHDp30 video consumes 200Mbps
  • A single stream of 1080i50/59.94 video consumes 100Mbps
  • A single stream of UHDp60 video consumes 250Mbps

NDI In Video Compression

Video streams can be transmitted over a network using NDI's compression technology. NewTek claims that NDI is one of the best efficient codecs on the market. 

Most codecs that have been accepted for broadcast use are significantly less efficient than NDI. At 250 frames per second, the codec can compress 1920x1080 video using a single core on a modern Intel-based i7 processor.

When using the NDI codec, typical video content has a peak signal-to-noise ratio (PSNR) of over 70dB. NDI is the first codec to offer multi-generational stability, making it a significant innovation. If you compress a video signal, you won't lose any data.

Regarding latency, NDI has a theoretical maximum of 16 video scan lines, but in practice, most implementations will only have one.

Conclusion

If we talk about sdi vs ndi, NDI clearly wins as it can support multiple video streams over a single local area network connection in a bidirectional fashion. Resolution and frame rate are not factors in the encoding algorithm's design; it can handle 4K and up to 16 floating-point audio channels. 

Video access rights, grouping, bi-directional metadata, and IP commands are also included in the protocol. And it's fantastic.

It is possible to switch facilities to an incredibly flexible IP video production pipeline thanks to the performance over standard GigE networks.