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S-VHS, the common initialism for Super VHS, is an Analog video video Videotape format introduced by JVC in 1987 as an improved 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 horizontal resolution of approximately 400 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-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.
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 such as the Victor HR-Z1 can additionally record a pulse-code modulation (PCM) digital audio track (stereo 48 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 MHz for the digital audio with O-QDPSK (Offset Quadrature Differential Phase Shift Keying) modulation and PCM encoding which is then recorded onto the same helical tracks as the video. This frequency is above those used for VHS Hi-Fi (1.7 MHz for the left channel, 1.8 MHz for the right channel) but below the luminance signal frequency for regular VHS of 3.4 MHz. The digital audio stream has a bit rate of 2.6 Mbps. 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 KHz. It is also possible for this audio channel to have a carrier frequency of 2 MHz.
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.
Later model S-VHS VCRs offered a recording option called 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.
Videophiles were the first to theorize that since the only distinguishing feature of an S-VHS tape is a small 3 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).
Studer produced the V-Eight (manufactured and sold by Alesis as the M20) 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.
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