View source for S-VHS

{{short description|Improved version of VHS}}
{{Distinguish|text=the video signal format [[S-Video]]}}
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{{tone|date=May 2025}}
{{Copy edit|date=May 2025}}
{{More citations needed|date=May 2025}}
{{Notability|date=May 2025}}
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{{Infobox storage medium
| name = S-VHS
| logo = S-VHS.svg{{!}}class=skin-invert
| image = Victor XG180 S-VHS videocassette.jpg
| caption = An S-VHS tape
| type = [[Magnetic tape cassette]]
| encoding = [[PAL]], [[NTSC]], [[ADAT]]
| capacity = 9 hours in [[super long play]] (SLP) mode on T-180, 10 hours in PAL-LP with E-300 tape (up to 15h in PAL-EP machines)
| read =
| write =
| standard = [[525 lines]], [[625 lines]]
| owner =
| use = [[Home video]], [[home movies]], [[video production]]
| extended from = [[VHS]]
| extended to = [[D-VHS]]{{,}}[[W-VHS]]
| released = {{Start date and age|1987|4}}
}}

'''Super VHS''', commonly abbreviated as '''S-VHS''', is an [[Analog video|analog]] video [[Videotape|cassette]] format introduced by [[JVC]] in 1987 as a more developed version of the [[VHS]] (Video Home System) format. S-VHS improved image quality by increasing the bandwidth of the [[luminance]] (brightness) signal, allowing for a [[image resolution|resolution]] of approximately 400 horizontal lines, compared to the 240 lines typical of VHS. The format used the same physical cassette shell as VHS but required higher-grade magnetic tape and compatible recording and playback equipment.

S-VHS decks are [[Backward compatibility|backward-compatible]] with standard VHS tapes, allowing them to play and record in VHS format. However, S-VHS tapes generally cannot be played in VHS-only machines, due to differences in the signal encoding.

Despite its technical advantages, S-VHS struggled to gain widespread consumer adoption due to the higher cost of equipment and tapes, along with the limited availability of pre-recorded content. The format found moderate success in professional, educational, and industrial applications, including video production, surveillance camera recording, and television broadcasting, where its higher resolution and compatibility with VHS tapes made it a practical transitional format.

==Technical information==
Like VHS, the S-VHS format uses a ''color under A'' [[modulation]] scheme.<ref name=Sencore>{{cite web|url=https://www.av-iq.com/AVCAT/images/documents/pdfs/TT189%20-%204611.pdf|title=Comparison Of VCR Formats - Sencore tech tips|work=Sencore|publisher=AV-iQ.com - NewBay Media, LLC|access-date=20 May 2016|archive-date=30 April 2016|archive-url=https://web.archive.org/web/20160430061412/http://www.av-iq.com/AVCAT/images/documents/pdfs/TT189%20-%204611.pdf|url-status=dead}}</ref> S-VHS improves [[Luma (video)|luminance]] (luma) resolution by increasing luminance [[Bandwidth (signal processing)|bandwidth]].<ref name=Sencore/> Increased bandwidth is possible because of the increased luminance [[Carrier signal|carrier]] from 3.4&nbsp;[[megahertz]] (MHz) to 5.4&nbsp;MHz.<ref name=Sencore/> The luminance modulator ''bandwidth'' also is increased: in contrast to standard VHS's frequencies of 3.8&nbsp;MHz (synch tip) to 4.8&nbsp;MHz (peak white), S-VHS uses 5.4&nbsp;MHz synch tip and 7.0&nbsp;MHz peak white.<ref>{{cite web | url=https://books.google.com/books?id=IuQDAAAAMBAJ&dq=s+vhs+5.4+mhz&pg=PA60 | title=Popular Mechanics | date=January 1988 | publisher=Hearst Magazines }}</ref><ref>{{cite book | url=https://books.google.com/books?id=NXEIVQrhKP4C&dq=s+vhs+5.4+mhz&pg=PA218 | title=VCR Troubleshooting and Repair | isbn=978-0-7506-9940-2 | last1=Capelo | first1=Gregory | last2=Brenner | first2=Robert C. | date=26 June 1998 | publisher=Newnes }}</ref> Increased luminance bandwidth produces a 60% improvement in luminance picture detail—a [[Television lines|horizontal resolution]] of 420 vertical lines per picture height,<ref name="Popular Mechanics">{{cite web | url=https://books.google.com/books?id=OOMDAAAAMBAJ&dq=s+vhs+420+lines&pg=PA66 | title=Popular Mechanics | date=October 1992 | publisher=Hearst Magazines }}</ref> versus VHS's 240 lines. The often quoted horizontal resolution of "over 400" means S-VHS captures greater picture detail than even [[NTSC]]<ref name=Sencore/> analog cable and broadcast TV, which is limited to about 330 television lines (TVL).<ref name="Popular Mechanics"/> In practice, when [[time shifting|time-shifting]] [[TV program]]s on S-VHS equipment, the improvement over VHS is noticeable. Yet, the trained eye can easily spot the difference between [[live television]] and an S-VHS recording of it. This is because S-VHS does not improve other key aspects of the video signal, particularly the [[chrominance]] (chroma) signal. In VHS, the chroma carrier is both severely [[bandlimited]] and [[Signal noise|noisy]], a limitation that S-VHS does not address. Lack of color resolution was a deficiency shared by S-VHS's contemporaries, such as [[Hi8]] and ED-Beta – all of which were limited to 0.4&nbsp;megahertz or 30&nbsp;TVL resolution.<ref name=Damjanovski>{{cite book|last=Damjanovski|first=Vlado|year=2005|title=CCTV: Networking and Digital Technology|url=https://books.google.com/books?id=MQZQIFaOhgoC|publisher=Elsevier/Butterworth-Heinemann|page=238|isbn=0-7506-7800-3}}</ref>

In [[audio recording]], S-VHS retains VHS's conventional linear ([[baseband]]) and [[high fidelity]] (Hi-Fi) – [[Audio Frequency Modulation]] (AFM) soundtracks. Some professional S-VHS decks, and high end domestic S-VHS VCRs<ref>{{cite web | url=https://patents.google.com/patent/JPH04258801A/en?q=(%22O-QDPSK%22)&oq=%22O-QDPSK%22 | title=磁気記録再生装置 }}</ref> such as the Victor HR-Z1  can additionally record a [[pulse-code modulation]] (PCM) [[digital audio]] track (stereo 48&nbsp;kHz), onto S-VHS tape along with normal video and Hi-Fi stereo and mono analog audio.

This is performed by using a high carrier frequency of 3&nbsp;MHz for the digital audio with O-QDPSK (Offset Quadrature Differential Phase Shift Keying) modulation and PCM encoding<ref>{{cite web | url=https://patents.google.com/patent/JP2584514B2/en?q=(%22O-QDPSK%22)+vhs&oq=(%22O-QDPSK%22)+vhs | title=磁気テープ記録再生装置 }}</ref><ref>{{cite web | url=https://patents.google.com/patent/JPH0832931A/en?q=(%22O-QDPSK%22)+vhs&oq=(%22O-QDPSK%22)+vhs | title=Ｐｃｍ音声ビデオカセットレコーダ }}</ref><ref>{{cite web | url=https://patents.google.com/patent/JPH05274752A/en?q=(%22O-QDPSK%22)&oq=%22O-QDPSK%22 | title=磁気記録再生装置のトラッキング制御システム }}</ref> which is then recorded onto the same helical tracks as the video. This frequency is above those used for VHS Hi-Fi (1.7&nbsp;MHz for the left channel, 1.8&nbsp;MHz for the right channel) but below the luminance signal frequency for regular VHS of 3.4&nbsp;MHz.<ref name="patents.google.com">{{cite web | url=https://patents.google.com/patent/EP0206203B1/en?q=(%22O-QDPSK%22)&oq=%22O-QDPSK%22 | title=Recording and reproducing apparatus using a modulator/Demodulator for Offset Quadrature Differential Phase-Shift Keying }}</ref><ref>{{cite web | url=https://archive.org/details/japanese-manual-83274/page/n143/mode/1up | title=Japanese manual 83274 : HR-Z1 の取扱説明書・マニュアル }}</ref><ref>{{Cite web | title=With digital ears and Super VHS eyes, enjoy the breathtaking expansion of the area | language=zh | url=https://www5d.biglobe.ne.jp/~umazaki/av/old/victor-z1.jpg | archive-url=https://web.archive.org/web/20040513202652/http://www5d.biglobe.ne.jp/~umazaki/av/old/victor-z1.jpg | archive-date=2004-05-13 | access-date=2024-08-24 | url-status=live }}</ref> The digital audio stream has a bit rate of 2.6 Mbit/s.<ref>{{cite web | url=https://patents.google.com/patent/JP2683119B2/en?q=(%22O-QDPSK%22)+mbit&oq=(%22O-QDPSK%22)+mbit&page=1 | title=信号多重記録方法及びその記録再生装置 }}</ref><ref>{{cite web | url=https://patents.google.com/patent/JP2584514B2/en?q=(%22O-QDPSK%22)+mbit&oq=(%22O-QDPSK%22)+mbit | title=磁気テープ記録再生装置 }}</ref><ref>{{cite web | url=https://patents.google.com/patent/JPH0719323B2/en?q=(%22O-QDPSK%22)+mbit&oq=(%22O-QDPSK%22)+mbit | title=磁気テープ記録再生装置 }}</ref><ref>{{cite web | url=https://patents.google.com/patent/JPH04258801A/en?q=(%22O-QDPSK%22)+mbit&oq=(%22O-QDPSK%22)+mbit | title=磁気記録再生装置 }}</ref> O-QDPSK is based on QDPSK (Quadrature Differential Phase Shift Keying), also known as DQPSK (Differential Quadrature Phase Shift Keying), and is very similar to it, except O-QDPSK signals are free from [[zero crossing]]; the signals never cross the 0 voltage point. Instead they are above and below the 0 voltage point. This type of digital audio requires a bandwidth of 500&nbsp;kHz. It is also possible for this audio channel to have a carrier frequency of 2&nbsp;MHz.<ref name="patents.google.com"/>

The bandwidth of S-VHS allows [[PAL]] recordings to contain [[Teletext]] data along with the normal video signal, which then can be displayed as an overlay of the conventional TV picture (though not on standard VHS machines). A suitably Teletext-equipped receiver/decoder (TV, PC card, etc.) displays the recorded Teletext data information as if the video were a television transmission being received at that moment.

===Hardware===
[[File:Panasonic NV-HS1000 S-VHS.jpg|thumb|Panasonic NV-HS1000 S-VHS VCR]]
S-VHS [[video cassette recorder]]s (VCRs) and cassette tapes are nearly identical in appearance and operation, and [[backward compatible]] with VHS. VHS VCRs cannot play back S-VHS recordings at all but can record onto an S-VHS tape in the basic VHS format.<ref>{{cite web|url=https://www.techradar.com/reviews/audio-visual/dvd-recorders/panasonic-dmr-ex99v-679559/review|title=Panasonic DMR-EX99V review|author=Martin Pipe|date=March 30, 2010|work=techradar}}</ref> Newer VHS VCRs, depending upon their specification, offered a feature called ''S-VHS quasi-playback'' or ''Super Quasi-Play Back'', abbreviated to SQPB. SQPB lets basic VHS players view (but not record) S-VHS recordings, though reduced to the lesser VHS quality. This feature is useful for viewing S-VHS [[camcorder]] recordings that use either the full-size S-VHS cassette or the smaller [[VHS-C|S-VHS-C]] cassette.

Later model S-VHS VCRs offered a recording option called [[#S-VHS ET|S-VHS ET]], which allowed SVHS VCRs to record on VHS tape. S-VHS ET is a further modification of the VHS standards that permitted near S-VHS quality recordings on more common and less expensive basic VHS tapes. S-VHS ET recordings can be viewed on most SQPB-equipped VHS VCRs and S-VHS VCRs.

To get the most benefit from S-VHS, a direct video connection to the monitor or TV is required, ideally via an [[S-Video]] connector and/or S-Video enabled [[SCART]].

[[File:Camera Super VHS-C, Panasonic NV-S77.jpg|thumb|Video recorder Super [[VHS-C]] Panasonic NV-S77]]

===Media===
In order to take advantage of the enhanced capabilities of the S-VHS system, i.e., for the best recordings and playback, an S-VHS VCR requires S-VHS [[video tape]] cassettes.<ref name=Sencore/> These have a different oxide media formulation for higher magnetic coercivity. S-VHS video cassettes are sensed and identified by the video cassette recorder via a specific internal profile within a hole in the underside of the S-VHS video cassette body.

Videophiles were the first to theorize that since the only distinguishing feature of an S-VHS tape is a small 3&nbsp;mm hole on the underside of the video cassette, it should be possible to use more common and inexpensive VHS tapes by duplicating that hole. However, S-VHS cassettes contain a higher grade and [[coercivity]] of tape stock to effectively record the higher video bandwidth offered by S-VHS.

S-VHS tapes can be used with VHS VCRs, but an S-VHS recording will not play back properly on a VHS VCR without SQPB (sound is usually reproduced correctly, but the picture quality will be poor).

===S-VHS ET===
JVC introduced an ''S-VHS ET'' (Super-VHS Expansion Technology) system on its S-VHS consumer decks, allowing the use of normal VHS tapes for S-VHS recording, by slightly modifying the S-VHS recording specs, while still retaining compatibility, so that S-VHS ET tapes could be played with non-ET S-VHS VCRs. In S-VHS ET mode, the recording circuit is altered with:
# Change of the W/D clip level (reducing the white clip level from 210% in SVHS to 190% in SVHS ET)
# Change of the main emphasis characteristics (changing the frequency responses)
# Change of the recording level ([[Luma (video)|Y]] and [[Chrominance|C]]) and recording current<ref>JVC Video Technical Guide - VIDEO CASSETTE RECORDER - HR-S9500 NTSC/PAL/SECAM, March 1999 - retrieved from http://www.digitalfaq.com/forum/vcr-repair/4768-service-manual-jvc.html (members only) on January 9, 2016</ref>

==Use for digital audio==
[[File:ADAT-XT.jpg|thumb|300px|An Alesis ADAT XT 8-channel digital audio recorder]]
In 1991, [[Alesis]] introduced [[ADAT]], an eight-track digital audio recording system that used S-VHS cassettes. An ADAT machine recorded eight tracks of uncompressed audio material in 16-bit (later 20-bit) resolution. The recording time was one-third of the cassette's nominal playing time, e.g., a 120-minute S-VHS cassette held 40 minutes of eight-track audio.

[[Studer]] produced the V-Eight (manufactured and sold by Alesis as the M20) <ref>{{Cite web|url=https://www.tangible-technology.com/studer/v81b.html|title=Studer V-Eight (Alesis M20) Product Review|website=www.tangible-technology.com|access-date=2018-07-28|archive-date=2022-11-17|archive-url=https://web.archive.org/web/20221117033110/https://www.tangible-technology.com/studer/v81b.html|url-status=dead}}</ref> and the V-Twenty-Four digital multitrack recorders. These used S-VHS cassettes for 8-track and 24-track digital audio recording, at a significantly lower cost than their DASH reel-to-reel digital recorders. The videotape transports were made for Studer by Matsushita.

==See also==
*[[D-VHS]]
*[[W-VHS]]
*[[Video 2000]]

==References==
{{Reflist}}

==External links==
{{Commons category|S-VHS}}
*{{usurped|1=[https://web.archive.org/web/20120402203526/http://www.high-techproductions.com/formats.htm Formats]}} — High-TechProductions.com

{{Video storage formats}}

{{DEFAULTSORT:S-Vhs}}
[[Category:Products introduced in 1987]]
[[Category:Videotape]]
[[Category:VHS]]
[[Category:Japanese inventions]]
[[Category:Videocassette formats]]
[[Category:Composite video formats]]