Editing Serial digital interface (section)

{{Short description|Family of digital video interfaces}}
{{About|the serial digital interface used in professional video|serial interfaces in general|serial communication}}
{{More citations needed|date=September 2008}}
{{Infobox technology standard
| title = SDI
| long_name = Serial digital interface
| native_name = <!-- Name in local language. If more than one, separate using {{plain list}} -->
| native_name_lang = <!-- ISO 639-2 code e.g. "fr" for French. If more than one, use {{lang}} inside native_name items instead -->
| image = BNC 75 ohm connector.jpg
| caption = Serial digital interface uses [[BNC connector]]s
| status = Active
| year_started = {{Start date|1989}}
| first_published = <!-- {{Start date|YYYY|MM|DD|df=y}} -->
| version = 24G
| version_date = 2020
| preview = 
| preview_date = 
| organization = [[SMPTE]] (The Society of Motion Picture and Television Engineers)
| committee = 
| editors = 
| authors = 
| base_standards = 
| related_standards = 
| predecessor = [[Composite_video | CVBS - Composite Video]]
| abbreviation = SDI / SD-SDI / HD-SDI / SDI 3G / SDI 6G / SDI 12G / SDI 24G /
| domain = 
| license = 
| website = <!-- {{URL|example.com}} -->
}}

'''Serial digital interface''' ('''SDI''') is a family of [[digital video]] [[Interface (computing)|interfaces]] first standardized by [[SMPTE]] (The Society of Motion Picture and Television Engineers) in 1989.<ref name="DVaH">{{cite book | title = Digital Video and HDTV | author = Charles A. Poynton | publisher = Morgan Kaufmann | year = 2003 | isbn = 978-1-55860-792-7 | url = https://books.google.com/books?id=ra1lcAwgvq4C&q=%22serial+digital+interface%22+SDI+SMPTE+259M+Rec-656+294M+344M&pg=RA1-PA130 }}</ref><ref name=Hudson>{{cite web |url=https://www.smpte.org/sites/default/files/2013-09-10-3GSDI-Hudson-V3-Handout.pdf |title=3Gb/s SDI for Transport of 1080p50/60, 3D, UHDTV1 / 4k and Beyond |date=2013 |author=John Hudson |access-date=2014-03-13 |archive-date=2016-03-04 |archive-url=https://web.archive.org/web/20160304053647/https://www.smpte.org/sites/default/files/2013-09-10-3GSDI-Hudson-V3-Handout.pdf |url-status=dead }}</ref> For example, [[ITU-R BT.656]] and [[SMPTE 259M]] define digital [[video interface]]s used for [[Broadcasting|broadcast]]-grade video. A related standard, known as '''high-definition serial digital interface''' (HD-SDI), is standardized in [[SMPTE 292M]]; this provides a nominal data rate of 1.485&nbsp;Gbit/s.<ref>{{cite book | url=https://books.google.com/books?id=-deC-tg7F9gC&q=Serial+digital+interface&pg=PA324 | title = Digital interface handbook | author = Francis Rumsey, John Watkinson| isbn = 9780240519098 | year = 2004 | publisher = Taylor & Francis }}</ref>

Additional SDI standards have been introduced to support increasing video resolutions ([[High definition video|HD]], [[Ultra high definition|UHD]] and beyond), [[High frame rate|frame rates]], [[3D video|stereoscopic (3D) video]],<ref>{{Cite web|url=https://www.provideocoalition.com/aja_introduces_hi5-3d_mini-converter_for_stereo_3d_monitoring/|title=AJA Introduces Hi5-3D Mini-Converter For Stereo 3D Monitoring by Scott Gentry – ProVideo Coalition|date=10 September 2010}}</ref><ref>{{Cite web | title=Archived copy | url=http://pro.jvc.com/pro/attributes/HDTV/manual/IF_2D3D1MANUAL_061810.pdf | archive-url=https://web.archive.org/web/20210508074255/http://pro.jvc.com/pro/attributes/HDTV/manual/IF_2D3D1MANUAL_061810.pdf | archive-date=2021-05-08}}</ref> and [[color depth]].<ref>{{Cite book|url=https://tech.ebu.ch/publications/tech3375|title=Signalling and Transport of HDR and Wide Colour Gamut Video over 3G-SDI Interfaces|date=May 23, 2020|via=tech.ebu.ch}}</ref> '''Dual link HD-SDI''' consists of a pair of SMPTE 292M links, standardized by [[SMPTE 372M]] in 1998;<ref name=Hudson/> this provides a nominal 2.970&nbsp;Gbit/s interface used in applications (such as [[digital cinema]] or HDTV 1080P) that require greater fidelity and resolution than standard HDTV can provide. '''3G-SDI''' (standardized in [[SMPTE 424M]]) consists of a single 2.970&nbsp;Gbit/s serial link that allows replacing dual link HD-SDI. '''6G-SDI''' and '''12G-SDI''' standards were published on March 19, 2015.<ref name="SDI2081March2015IEEE">{{cite conference |title=ST 2081-10:2015 – 2160-Line and 1080-Line Source Image and Ancillary Data Mapping for Single-Link 6G-SDI   |publisher=IEEE |date=2015-03-19 |doi=10.5594/SMPTE.ST2081-10.2015 |isbn=978-1-61482-857-0 }}</ref><ref name="SDI2082March2015IEEE">{{cite conference |title=ST 2082-10:2015 - 2160-line Source Image and Ancillary Data Mapping for 12G-SDI  |publisher=IEEE |date=2015-03-19 |doi=10.5594/SMPTE.ST2082-10.2015 |isbn=978-1-61482-860-0 }}</ref>

These standards are used for transmission of [[Uncompressed video|uncompressed, unencrypted digital video]] signals (optionally including embedded audio and time code) within television facilities; they can also be used for packetized data. SDI is used to connect together different pieces of equipment such as recorders, monitors, PCs and vision mixers. Coaxial variants of the specification range in length but are typically less than {{Convert|300|m|sp=us}}. Fiber optic variants of the specification such as 297M allow for long-distance transmission limited only by maximum fiber length or repeaters. 

SDI and HD-SDI are usually available only in professional video equipment because various [[licensing]] agreements restrict the use of unencrypted digital interfaces, such as SDI, prohibiting their use in consumer equipment. Several professional video and HD-video capable [[DSLR]] cameras and all uncompressed video capable consumer cameras use the [[HDMI]] interface, often called [[clean HDMI]]. There are various [[mod kit]]s for existing [[DVD player]]s and other devices such as splitters that ignore [[HDCP]], which allow a user to add a serial digital interface to these devices.{{citation needed|date=September 2014}}