When we talk about HDTV, we’re typically talking about any one of a number of standards from when television made the paradigm switch from analog to digital transmission. At the dawn of the new millenium, high-definition TV was a step-change for the medium, perhaps the biggest leap forward since color transmissions began in the middle of the 20th century.

However, a higher-resolution television format did indeed exist well before the TV world went digital. Over in Japan, television engineers had developed an analog HD format that promised quality far beyond regular old NTSC and PAL transmissions. All this, decades before flat screens and digital TV were ever seen in consumer households!

Resolution

Japan’s efforts to develop a better standard of analog television were pursued by the Science and Technical Research Laboratories of NHK, the national public broadcaster. Starting in the 1970s, research and development focused on how to deliver a higher-quality television signal, as well as how to best capture, store, and display it.

The higher resolution of Hi-Vision was seen to make viewing a larger, closer television more desirable. The figures chosen were based on an intended viewing distance that of three times the height of the screen. Credit: NHK Handbook

This work led to the development of a standard known as Hi-Vision, which aimed to greatly improve the resolution and quality of broadcast television. At 1125 lines, it offered over double the vertical resolution of the prevailing 60 Hz NTSC standard in Japan. The precise number was chosen for meeting minimum requirements for image quality for a viewer with good vision, while being a convenient integer ratio to NTSC’s 525 lines (15:7), and PAL’s 625 lines (9:5). Hi-Vision also introduced a shift to the 16:9 aspect ratio from the more traditional 4:3 used in conventional analog television. The new standard also brought with it improved audio, with four independent channels—left, center, right, and rear—in what was termed “3-1 mode.” This was not unlike the layout used by Dolby Surround systems of the mid-1980s, though the NHK spec suggests using multiple speakers behind the viewers to deliver the single rear sound channel.

Hi-Vision offered improved sound, encoded with PCM. Credit: NHK handbook

Hi-Vision referred most specifically to the video standard itself; the broadcast standard was called MUSE—standing for Multiple sub-Nyquist Sampling Encoding. This was a method for dealing with the high bandwidth requirements of higher-quality television. Where an NTSC TV broadcast might only need 4.2 MHz of bandwidth, the Hi-Vision standard needed 20-25 MHz of bandwidth. That wasn’t practical to fit in alongside terrestrial broadcasts of the time, and even for satellite delivery, it was considered too great. Thus, MUSE offered a way to compress the high-resolution signal down into a more manageable 8.1 MHz, with a combination of dot interlacing and advanced multiplexing techniques. The method used meant that ultimately four frames were needed to make up a full image. Special motion-sensitive encoding techniques were also used to limit the blurring impact of camera pans due to the use of the dot interlaced method. Meanwhile, the four-channel digital audio stream was squeezed into the vertical blanking period.

MUSE broadcasts began on an experimental basis in 1989. NHK would eventually begin using the standard regularly on its BShi satellite service, with a handful of other Japanese broadcasters eventually following suit. Broadcasts ran until 2007, when NHK finally shut down the service with digital TV by then well established.

An NHK station sign-on animation used from 1991 to 1994.

A station ident from NHK’s Hi-Vision broadcasts from 1995 to 1997. Note the 16:9 aspect ratio—then very unusual for TV. Credit: NHK

The technology wasn’t just limited to higher-quality broadcasts, either. Recorded media capable of delivering higher-resolution content also permeated the Japanese market. W-VHS (Wide-VHS) hit the market in 1993 as a video cassette standard capable of recording Hi-Vision/MUSE broadcast material. The W moniker was initially chosen for its shorthand meaning in Japanese of “double”—since Hi-Vision used 1125 lines which was just over double the 525 lines in an NTSC broadcast.

Later, in 1994, Panasonic released its Hi-Vision LaserDisc player, with Pioneer and Sony eventually offering similar products. They similarly offered 1,125 lines (1,035 visible) of resolution in a native 16:9 aspect ratio. The discs were read using a narrower-wavelength laser than standard laser discs, which also offered improved read performance and reliability.

Sample video from a MUSE Hi-Vision Laserdisc. Note the extreme level of detail visible in the makeup palettes and skin, and the motion trails in some of the lens flares.

The hope was that Hi-Vision would become an international standard for HDTV, supplanting the ugly mix of NTSC, PAL, and SECAM formats around the world. Unfortunately, that never came to pass. While Hi-Vision and MUSE did offer a better quality image, there simply wasn’t much content that was actually broadcast in the standard. Only a few channels in Japan were available, creating a limited incentive for households to upgrade their existing sets. Similarly, the amount of recorded media available was also limited. The bandwidth requirements were also too great; even with MUSE squishing the signals down, the 8.1MHz required was still considered too much for practical use in the US market. Meanwhile, being based on a 60 Hz standard meant the European industry was not interested.

Further worsening the situation was that by 1996, DVD technology had been released, offering better quality and all the associated benefits of a digital medium. Digital television technology was not far behind, and buildouts began in countries around the world by the late 1990s. These transmissions offered higher quality and the ability to deliver more channels with the same bandwidth, and would ultimately take over.

Only a handful of Hi-Vision displays still exist in the world.

Hi-Vision and MUSE offered a huge step up in image quality, but their technical limitations and broadcast difficulties meant that they would never compete with the new digital technologies that were coming down the line. There was simply not enough time for the technology to find a foothold in the market before something better came along. Still, it’s quite something to look back on the content and hardware from the late 1980s and early 1990s that was able, in many ways, to measure up in quality to the digital flat screen TVs that wouldn’t arrive for another 15 years or so. Quite a technical feat indeed, even if it didn’t win the day!