Network Device Interface: Difference between revisions

Revision as of 01:01, 9 September 2024

Revision as of 15:10, 21 October 2024

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==Technology==

NDI is designed to run over [[gigabit Ethernet]]<ref>{{cite web|url=https://www.provideocoalition.com/newtek-announces-ndi-an-open-protocol-for-ip-production-workflow/|title=NewTek announces NDI, an open protocol for IP production workflow by Allan Tépper|first=ProVideo|last=Coalition|date=8 September 2015}}</ref> with the NDI codec.<ref>{{cite web|url=http://support.newtek.com/hc/en-us/articles/218109667-NDI-Encoding-Decoding|title=NDI Encoding/Decoding|website=NewTek Knowledge Base}}</ref> It delivers [[1080i]] [[high-definition video]] at [[variable bitrate|variable data rate]]s typically around 100&nbsp;Mbit/s.<ref>{{cite web|url=https://support.newtek.com/hc/en-us/articles/217662708-NDI-Network-Bandwidth|title=NDI Network Bandwidth|website=NewTek Knowledge Base}}</ref><!--[[User:Kvng/RTH]]-->

By default, NDI uses the [[mDNS]]multicast ([[Bonjour (software)|BonjourDNS]] / [[Zeroconf]]) discovery mechanism to advertise sources on a [[local area network]], such that NDI receiving devicesreceivers can automatically discover and offer those sources. It also supports 2two other discovery modes (NDI Access, NDI Discovery Server) that allow for operations across [[subnet]]s and without mDNSmulticast DNS. Sources are created using an arbitrarily selected [[Transmission Control Protocol|TCP]] [[Port (computer networking)|port]] from a range of ports on the NDI send hostsenders. When a source is requested, a TCP connection is established on the appropriate port with the NDI receiver connecting to the NDI sender. NDI 3.x has options to use [[User Datagram Protocol|UDP]] [[multicast]] or [[unicast]] with [[forward error correction]] (FEC) instead of TCP, and can [[Load balancing (computing)|load balance]] streams across multiple [[network interface controller]]s (NICs) without using [[link aggregation]]. The release of NDI version 4.0 introduces the ''Multi-TCP'' transport.<!--[[User:Kvng/RTH]]-->

NDI carries video, multichannel [[uncompressed audio]],{{Citation needed|date=September 2020|reason=Please link to an official source verifying this claim}} and [[metadata]]. Metadata messages can be sent in both directions allowing the sender and receiver to message one another over the connection with arbitrary metadata in [[XML]] form.<ref>{{cite web|url=http://www.content-technology.com/standards/?p=578|title=NewTek Announces NDI – Open Protocol for IP Production Workflow - Technical Standards|website=Content-technology.com}}</ref> This directional metadata system allows for functionality such as active [[Tally light|tally information]] fed back to sources to understand that they are on-air (program / preview). NDI also allows senders to determine the number of connected receivers, so they can skip unnecessary processing and network bandwidth utilisation when there are no NDI receiver clients connected. NDI Receivers can opt to connect to various combinations of streams, to support things like audio-only or metadata-only connections where video is not required.