A standard 4-pin S-Video cable connector, with each signal pin paired with its own ground pin.
|Type||Analog video connector|
|Video signal||NTSC, PAL, or SECAM video|
|Pins||4, 7, or 9|
|Looking at the female connector|
|Pin 1||GND||Ground (Y)|
|Pin 2||GND||Ground (C)|
|Pin 3||Y||Intensity (Luminance)|
|Pin 4||C||Colour (Chrominance)|
|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.|
Separate Video, commonly known as S-Video, Super-video and Y/C, is a signalling standard for standard definition video, typically 480i or 576i. By separating the black-and-white and colouring signals, it achieves better image quality than composite video, but has lower colour resolution than component video.
The S-video cable carries video using two synchronised signal and ground pairs, termed Y and C.
Y is the luma signal, which carries a complete black-and-white picture, including synchronization pulses.
C is the chroma signal, which carries the chrominance - or colouring-in - of the picture. This signal contains both the saturation and the hue of the video.
The luminance signal carries horizontal and vertical sync pulses in the same way as a composite video signal. Luma is a signal carrying luminance after gamma correction, and is therefore termed "Y" because of the similarity to the lower-case Greek letter gamma.
In composite video, types of cross-talk can be readily visible.
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.
Compared with component video, which carries the identical luminance signal but separates the colour-difference signals into Cb/Pb and Cr/Pr, the colour resolution of S-Video is limited by the modulation on a subcarrier frequency of 3.57 to 4.43 Megahertz, depending on the standard. It is worth noting that this difference is meaningless on consumer videotape systems, as the chrominance is already severely constrained by both VHS and Betamax.
In addition, S-Video suffers from low color resolution. NTSC S-Video color resolution is typically 120 lines horizontal (approximately 160 pixels edge-to-edge), versus 250 lines horizontal for the Rec. 601-encoded signal of a DVD, or 30 lines horizontal for standard VCRs.
In many European Union countries, S-Video is less common because of the dominance of SCART, which allows RGB quality and is usually fitted to every TV. It is not usual to find S-Video outputs on equipment such as DVD players, although the player may output S-Video over SCART, but the TV may not be compatible with S-Video wired this way, and so would just show a monochrome image. In this case it is sometimes possible to modify the SCART adapter cable to make it work. Games consoles usually do not output S-Video, due to the dominance of SCART with its better RGB quality. However, in the US and other non-SCART countries, S-Video is provided but no RGB. The Nintendo 64 was an exception – NTSC models could output S-Video, but only with modification could they output RGB. PAL Nintendo 64 models could output S-Video but not RGB, despite that being the easiest way to connect if done via SCART. There is, however, a German company that is able to modify PAL N64's to output true RGB, although this service is rather expensive compared to the way you can make an NTSC model output RGB.
Before the mini-DIN plug became standard, S-Video signals were often carried through different types of connectors. For example, the Commodore 64 home computer of the 1980s, one of the first widely available devices to feature an output similar to S-Video. It used an eight-pin DIN connector on the computer end and a pair of phono plugs on the monitor end to hookup separate luminance and chrominance, the latter with a higher signal level than standard S-video. (Also available via third-party vendors was an eight-pin DIN-to-4-pin mini-DIN to connect the Commodore directly to a television.) The S-Video connector is the most common video-out connector on older laptop computers; however, many devices with S-Video outputs also have composite outputs.
The Atari 800 home computer featured S-Video outputs in 1979 (three years before the Commodore 64), via a five-pin DIN plug.
At least some Fujitsu laptops (S-7020, S-7110) use so-called mini S-Video connector for TV-Out. This mini S-Video connector is actually a 3.5mm TRS connector where tip and ring carry Y/C, both using the sleeve as ground. Such a mini S-Video is rare, and it is very difficult to obtain a proprietary cable for it.
In Japan, MSX 2+ and MSX Turbo-R models from Panasonic featured standard S-Video output, some X68000 computers from Sharp (like the X68030) also feature S-Video output.
The four-pin mini-DIN connector (shown at right) is the most common of several S-Video connector types. Other connector variants include seven-pin locking "dub" connectors used on many professional S-VHS machines, and dual "Y" and "C" BNC connectors, often used for S-Video patch panels. 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 colour 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.
Non-standard 7-pin mini-DIN connectors (known as "7P") are used in some computer equipment (PCs and Macs). A 7-pin socket accepts and is pin compatible with a standard 4-pin S-Video plug. The three extra sockets may be used to supply composite (CVBS), an RGB or YPbPr video signal, or an I²C interface. The pin out usage varies between manufacturers. In some implementations, the remaining pin needs to be grounded to enable the composite output or disable the S-Video output.
9-pin Video In/Video Out
9-pin connectors are used in graphics systems that feature the ability to input video as well as output it. 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.
- Audio and video connector
- RF connector
- Composite monitor
- List of video connectors
- Video In Video Out (VIVO)
- S-Video – Definition About.com
- S-Video drama :(. camp0s.com
- shop – Umbau N64 PAL auf RGB incl. RGB Booster Kabel 8382. Wolfsoft.de. Retrieved on 2013-04-17.
- JVC Color Television User’s Guide. resources.jvc.com
- JVC USA Store – VC-S130HG – S-Video Cable. Store.jvc.com. Retrieved on 2013-04-17.
- Keith Jack (2007). Video demystified: a handbook for the digital engineer. Newnes. p. 69.
- ATI Radeon 7 pin SVID pinout.
- Dell (2009). "S-Video to TV-Composite Cable and SPDIF Adapter for Dell Inspiron".
- ATI Radeon: Using Video in and Video out.
- "ATI Radeon 9 pin VIVO pinout".
- This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.