Network Device Interface: Difference between revisions

Revision as of 16:03, 28 April 2024

Revision as of 14:25, 10 May 2024

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By default, NDI uses the [[mDNS]] ([[Bonjour (software)|Bonjour]] / [[Zeroconf]]) discovery mechanism to advertise sources on a local area network, such that NDI receiving devices can automatically discover and offer those sources. It also supports 2 other discovery modes (NDI Access, NDI Discovery Server) that allow for operations across [[subnet]]s and without mDNS. Sources are created using an arbitrarily selected [[Transmission Control Protocol|TCP]] [[Port (computer networking)|port]] from a range of ports on the NDI send host. 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.

NDI carries video, multichannel [[uncompressed audio|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 utilisationutilization 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.

The NDI [[software development kit]] (SDK) is available for [[Microsoft Windows|Windows]], [[Linux|Linux,]] and [[MacOS]],<ref>{{cite web|url=https://www.newtek.com/ndi/sdk/|title=NewTek NDI SDK|website=Newtek.com}}</ref> and has also been ported to [[iOS]], [[tvOS]], [[Android (operating system)|Android]], [[Raspberry Pi]], and [[Field-programmable gate array|FPGA]]. The Standard NDI SDK is available via a royalty-free [[Proprietary_software|proprietary]] license.<ref>{{cite web |title=NDI® license agreement |url=http://new.tk/ndisdk_license/ |website=new.tk |accessdate=3 June 2020}}</ref> The NDI Advanced SDK offers OEMs direct access to and from compressed data and other features, with a commercial license.

==Comparison of common IP video protocols==

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==History==

NDI was publicly revealed by NewTek on 8 September 2015 and was demonstrated at the IBC broadcast exhibition in Amsterdam that week.<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|date=8 September 2015|website=Provideocoalition.com}}</ref> The first device shown using NDI was the NewTek [[TriCaster]] which delivered an NDI feed from each of its SDI inputs as well as four output feeds from its vision mixer. The TriCaster could also receive up to two NDI sources from other devices (increased to 12 in later releases and up to 44 in NewTek's IP Series ).<ref>{{cite web|url=http://www.sportsvideo.org/2016/09/19/newteks-will-waters-says-ip-series-will-appeal-to-new-markets/|title=NewTek's IP Series Video-Production System Targets New Markets|first1=Ken|last1=Kerschbaumer|date=September 19, 2016|website=Sports Video Group}}</ref>

NewTek had previously created a predecessor of NDI called AirSend to get video from external devices into their TriCaster products. AirSend had been implemented by a number of [[character generator]] (CG) vendors including [[Vizrt]] and [[ChyronHego|Chyron]]. In order to quickly bring these products into the NDI space, NewTek created a new driver to replace the existing AirSend driver, which could be installed on these existing AirSend-compatible devices, instantly converting them to NDI-compatible devices with no change required by the original CG vendors.<ref>{{cite web|url=http://pages.newtek.com/NDI-Upgrader-Download.html|title=NDI AirSend Updater-NewTek|website=pages.newtek.com}}</ref>