Editing S-Video

{{Short description|Signal format for standard-definition video}}
{{Use American English|date = March 2019}}

{{Infobox connector
|name=S-Video
|type=Analog video connector
|image=[[File:SVideoConnector.jpg|300px|border]]
|logo=
|caption=A standard 4-pin S-Video male connector on a cable
|designer=
|design_date=1987
|manufacturer=
|production_date=
|superseded=
|superseded_by=
|superseded_by_date=
|external=Yes
|hotplug=Yes
|length=
|width=
|height=
|electrical=
|ground=
|maximum_voltage=
|maximum_current=
|audio_signal=
|video_signal=NTSC, PAL, or SECAM video
|data_signal=
|data_bit_width=
|data_bandwidth=
|data_devices=
|data_style=
|cable=
|physical_connector=[[Mini-DIN connector]]
|num_pins=4, 7, or 9
|pinout_col1_name=
|pinout_col2_name=
|pinout_image=[[Image:MiniDIN-4 Connector Pinout.svg|170px]]
|pinout_caption= Looking at the female connector.
|pin1=Ground (Y)
|pin1_name=GND
|pin2=Ground (C)
|pin2_name=GND
|pin3=Intensity (Luminance)
|pin3_name=Y
|pin4=Color (Chrominance)
|pin4_name=C
|pinout_notes=The shells should be connected together by an overall screen/shield. However, the shield is often absent in low-end cables, which can result in picture degradation.<br />Same connector as [[Apple Desktop Bus]].
}}

'''S-Video''' (also known as '''separate video''', '''Y/C''', and erroneously '''Super-Video''')<ref>[http://desktopvideo.about.com/od/s/g/svideo.htm S-Video – Definition] {{Webarchive|url=https://web.archive.org/web/20160301121642/http://desktopvideo.about.com/od/s/g/svideo.htm |date=2016-03-01 }} About.com</ref> is an [[analog video]] signal format that carries [[standard-definition video]], typically at [[525 lines]] or [[625 lines]]. It encodes video [[luma (video)|luma]] and [[chrominance]] on two separate channels, achieving higher image quality than [[composite video]] which encodes all video information on one channel. It also eliminates several types of visual defects such as [[dot crawl]] which commonly occur with composite video. Although it is improved over composite video, S-Video has lower color resolution than [[YPbPr|component video]], which is encoded over three channels.<ref>{{cite book |last=Poynton |first=Charles |date=2002 |title=Digital Video and HD: Algorithms and Interfaces |url=https://doc.lagout.org/science/0_Computer%20Science/Digital%20Video%20And%20HDTV%20Algorithms%20And%20Interfaces.pdf |publisher=Morgan Kaufmann |page=107 |isbn=1558607927|edition=First }}</ref>

The [[Atari 8-bit computers|Atari 800]] was the first to introduce separate Chroma/Luma output in late 1979.<ref name="8-bit FAQ">{{cite web |url=ftp://rtfm.mit.edu/pub/faqs/atari-8-bit/faq |title=Atari 8-bit FAQ |last=Current |first=Michael |access-date=2018-02-23 }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> However, S-Video was not widely adopted until [[JVC]]'s introduction of the [[S-VHS]] (Super-VHS) format in 1987, which is why it is sometimes incorrectly referred to as ''Super-Video''.<ref>{{Cite web|url=https://www.pcmag.com/encyclopedia/term/s-vhs|title=Definition of S-VHS}}</ref> 

The S-video format was widely adopted in consumer equipment due to its improvements over composite video. However, it was rarely used by professional studios and broadcasters as [[Component video|component]] [[YPbPr]] was superior for signal processing and [[standard-definition video|standard-definition]] TV was broadcast over NTSC composite signals.<ref>{{cite tech report |last=Pensinger |first=Glen |date=2002 |title=Introduction to Digital Television |url=http://www.cinemasource.com/articles/Intro_digital_tv.pdf |work=CinemaSource Technical Bulletins |location=Durham, NH 03824 |publisher=The CinemaSource Press |url-status=dead |archive-url=https://web.archive.org/web/20030507081248/http://www.cinemasource.com/articles/Intro_digital_tv.pdf |archive-date=2003-05-07 |access-date=2025-05-17 }}</ref>
<ref>{{cite book |last=Poynton |first=Charles |date=2002 |title=Digital Video and HD: Algorithms and Interfaces |url=https://doc.lagout.org/science/0_Computer%20Science/Digital%20Video%20And%20HDTV%20Algorithms%20And%20Interfaces.pdf |publisher=Morgan Kaufmann |page=107 |isbn=1558607927|edition=First }}</ref>

==Background==
{{unreferenced section|date=August 2020}}
Standard [[analog television]] signals go through several processing steps on their way to being broadcast, each of which discards information and lowers the quality of the resulting images.

The image is originally captured in [[RGB]] form and then processed into three signals known as [[YPbPr]]. The first of these signals is called '''Y''', which is created from all three original signals based on a formula that produces an overall brightness of the image, or ''[[luma (video)|luma]]''. This signal closely matches a traditional [[black and white television]] signal and the Y/C method of encoding was key to offering [[backward compatibility]]. Once the Y signal is produced, it is subtracted from the blue signal to produce '''Pb''' and from the red signal to produce '''Pr'''. To recover the original RGB information for display, the signals are mixed with the Y to produce the original blue and red, and then the sum of those is mixed with the Y to recover the green.

A signal with three components is no easier to broadcast than the original three-signal RGB, so additional processing is required. The first step is to combine the Pb and Pr to form the '''C''' signal, for [[chrominance]]. The phase and amplitude of the signal represent the two original signals. This signal is then [[Bandwidth (signal processing)|bandwidth]]-limited to comply with requirements for broadcasting. The resulting Y and C signals are mixed together to produce [[composite video]]. To play back composite video, the Y and C signals must be separated, and this is difficult to do without adding artifacts.

Each of these steps is subject to deliberate or unavoidable loss of quality. To retain that quality in the final image, it is desirable to eliminate as many of the encoding/decoding steps as possible. S-Video is an approach to this problem. It eliminates the final mixing of C with Y and subsequent separation at playback time.

==Signal==
The S-video cable carries video using two synchronized signal and ground pairs, termed Y and C. Y is the ''luma'' signal, which carries the ''luminance''&nbsp;– or black-and-white&nbsp;– of the picture, including synchronization pulses. Y also carries horizontal and vertical sync pulses in the same way as a [[composite video]] signal. C is the ''chroma'' signal, which carries the ''[[chrominance]]''&nbsp;– or coloring-in&nbsp;– of the picture. This signal contains two color-difference components.

In composite video, the signals co-exist on different frequencies. To achieve this, the luminance signal must be low-pass filtered, dulling the image. As S-Video maintains the two as separate signals, such detrimental low-pass filtering for luminance is unnecessary, although the chrominance signal still has limited bandwidth relative to component video.{{cn|date=November 2024}}

Carrying the color information as one signal means that the color has to be encoded in some way, typically in accord with [[NTSC]], [[PAL]], or [[SECAM]], depending on the applicable local standard.

Compared with [[component video]], which carries the identical luminance signal but separates the color-difference signals into Cb/Pb and Cr/Pr, the color resolution of S-Video is limited by the modulation on a [[subcarrier]] frequency of either {{val|3.58|ul=MHz}} (NTSC) or {{val|4.43|u=MHz}} (PAL). This difference is meaningless on home videotape systems, as the chrominance is already severely constrained by both [[VHS]] and [[Betamax]].

==Physical connectors==
===Atari 800===
[[File:DIN-5 Diagram.svg|left|65x65px]]
The [[Atari 8-bit computers|Atari 800]] introduced separate Chroma/Luma output in late 1979. The signals were put on pin 1 and 5 of a 5-pin 180-degree [[DIN connector]] socket. Atari did not sell a monitor for its 8-bit computer line, however.<ref name="8-bit FAQ"/>

===Commodore 64===
[[File:DIN-8 Diagram.svg|left|65x65px]]
The [[Commodore 64]] released in 1982 (with the exception of the earliest revisions using a 5-pin video port) also offers separate chroma and luma signals using a different connector. Although [[Commodore Business Machines]] did not use the term ''S-Video'' as the standard did not formally exist until 1987, a simple adapter connects the computer's LCA (luma-chroma-audio) 8-pin DIN socket to a S-Video display, or an S-Video device to the Commodore 1702 monitor's LCA jacks.<ref name="8bitguy20180511">{{Cite video |url=https://www.youtube.com/watch?v=BpXFB8ZEH30#t=9m38s  |archive-url=https://ghostarchive.org/varchive/youtube/20211211/BpXFB8ZEH30| archive-date=2021-12-11 |url-status=live|title=Commodore History Part 3 - The Commodore 64 (complete)|date=2018-05-11 |last=Murray |first=David |publisher=YouTube |series=The 8-Bit Guy |time=9:38 |access-date=2018-05-12}}{{cbignore}}</ref>

===4-pin mini-DIN===
[[File:MiniDIN-4 Diagram.svg|left|65x65px]]
The four-pin [[mini-DIN connector]] is the most common of several S-Video connector types. The same mini-DIN connector is used in the [[Apple Desktop Bus]] for Macintosh computers. Apple Desktop Bus cables can be used for S-Video in a pinch.<ref>{{cite web|url=https://support.apple.com/kb/TA35008?locale=en_US|title=Macintosh: S-Video Port Confused with the ADB Port|access-date=2015-04-27|archive-date=2016-05-12|archive-url=https://web.archive.org/web/20160512155657/https://support.apple.com/kb/TA35008?locale=en_US|url-status=dead}}</ref><ref>{{cite book|url=https://books.google.com/books?id=4yXVZYMd-q4C&q=adb%20s-video&pg=PA86|title=Compression for Great Digital Video: Power Tips, Techniques, and Common Sense|isbn=9781578201112|last1=Waggoner|first1=Ben|year=2002|publisher=Taylor & Francis }}</ref><ref>{{cite book|url=https://books.google.com/books?id=KH0rBgAAQBAJ&q=adb%20s-video&pg=PA451|title=A Practical Guide to Video and Audio Compression: From Sprockets and Rasters to Macro Blocks|isbn=9781136036101|last1=Wootton|first1=Cliff|date=28 April 2005|publisher=CRC Press }}</ref> Other connector variants include seven-pin locking ''dub'' connectors used on many professional S-VHS machines, and dual Y and C [[BNC connector]]s, often used for S-Video [[patch panel]]s. Early Y/C video monitors often used phono ([[RCA connector]])  that were switchable between Y/C and composite video input. Though the connectors are different, the Y/C signals for all types are compatible.

The mini-DIN pins, being weak, sometimes bend. This can result in the loss of color or other corruption (or loss) in the signal. A bent pin can be forced back into shape, but this carries the risk of the pin breaking off.

These plugs are usually made to be plug-compatible with S-video, and include optional features, such as [[component video]] using an adapter. They are not necessarily S-video, although they can be operated in that mode.

===7-pin mini-DIN===
[[Image:Pseudo miniDIN-7 Diagram.svg|left|64px|7-pin plug diagram]]

Non-standard 7-pin mini-DIN connectors (termed ''7P'') are used in some computer equipment (PCs and Macs). A 7P socket accepts, and is pin compatible with, a standard 4-pin S-Video plug.<ref name="pin7"/> The three extra sockets may be used to supply [[Composite video|composite (CVBS)]], an RGB or YPbPr video signal, or an [[I²C]] interface. The [[pinout]] usage varies among manufacturers.<ref name="pin7">{{cite book |title=Video demystified: a handbook for the digital engineer |author=Keith Jack |publisher=Newnes |year=2007 |isbn=9780750678223 |url=https://books.google.com/books?id=Kp5J7G8kXN4C&q=Video%20demystified%3A%20a%20handbook%20for%20the%20digital%20engineer.%20Newnes.%20p.%2069.&pg=PA69}}</ref><ref>{{cite book |title=ATI Radeon 7 pin SVID pinout|url=https://pinoutguide.com/Video/svideo_7pin_pinout.shtml}}</ref> In some implementations, the remaining pin must be grounded to enable the composite output or disable the S-Video output.

Some Dell laptops have a [[S/PDIF|digital audio output]] in a 7-pin socket.
<ref name="spdif">
{{cite web 
| title=S-Video to TV-Composite Cable and SPDIF Adapter for Dell Inspiron 
| author=Dell
| year=2009
| url=http://accessories.us.dell.com/sna/productdetail.aspx?c=ca&l=en&s=gen&sku=310-8274 
}}
</ref>

===8-pin mini-DIN===

[[Image:MiniDIN-8 Diagram.svg|65px|A MiniDIN-8 Diagram]]
The 8-pin mini-DIN connector is used in some [[ATI Radeon]] video cards<ref name="8-pin">{{cite web | title=ATI Radeon 8-pin audio / video VID IN connector pinout | author=Pinouts.Ru | year=2017
| url=https://pinouts.ru/Video/ati_video_pinout.shtml&usg=ALkJrhjYg-klUa0V7qOqqbVPDHFy9Rdp5A }}</ref>

===9-pin Video In/Video Out===

[[Image:Pseudo miniDIN-9 Diagram.svg]]
[[Image:MiniDIN-9 Diagram.svg|65px]]

9-pin connectors are used in graphics systems that feature the ability to input video as well as output it.<ref>ATI Radeon: Using Video in and Video out.</ref><ref>{{cite web|title=ATI Radeon 9 pin VIVO pinout|url=http://pinouts.ru/Video/radeon_vivo_pinout.shtml}}</ref> Again, there is no standardization between manufacturers as to which pin does what, and there are two known variants of the connector in use. As can be seen from the diagram above, although the S-Video signals are available on the corresponding pins, neither variant of the connector will accept an unmodified 4-pin S-Video plug, though they can be made to fit by removing the key from the plug. In the latter case, it becomes all too easy to misalign the plug when inserting it with consequent damage to the small pins.

==Comparison with SCART==
{{more citations needed section|date=January 2017}}
[[File:S-video-composite-adapter.svg|thumbnail|right|300px|S-video/composite adapter]]

In many European countries, S-Video was less common because of the dominance of [[SCART]] connectors, which were present on televisions until the advent of [[HDMI]]. It is possible for a player to output S-Video over SCART, but televisions' SCART connectors are not always wired to accept it, and if not the display would show only a monochrome image.<ref>[https://web.archive.org/web/20070208210842/http://www.camp0s.com/pc_related/svideo/svideo.php S-Video drama :](. camp0s.com</ref> In this case it is sometimes possible to modify the SCART adapter cable to allow full S-Video compatibility.<!-- <ref>[http://www.bertold.org/en/Electronics/tv-out-black-and-white.html Modify a S-Video to SCART cable for color picture] bertold.org</ref> (SGS – removed broken link)-->

==See also==
* [[Audio and video interfaces and connectors]]
* [[RF connector]]
* [[Composite monitor]]
* [[List of video connectors]]
* [[Video-in video-out|Video In Video Out (VIVO)]]

==References==
{{reflist}}

{{commons category|S-Video connectors}}

{{Analogvideo}}
{{AVconn}}
{{Audio_and_video_interfaces_and_connectors}}

[[Category:Audiovisual introductions in 1987]]
[[Category:Analog video connectors]]
[[Category:Film and video technology]]
[[Category:Video signal]]