W-VHS is a HDTVanalog recordingvideocassette format created by JVC. The format was originally introduced in 1994 for use with Japan's Hi-Vision, an early analog high-definition television system. In Japan, the letter "W" is often used as shorthand for the English word "double". The recording medium of W-VHS is a ½-inch double-coated MPtape stored in a cartridge the samesize as VHS. The tape can be used to store 1035i or 480i and a double channel of 480i analog signals. The video signal is recorded using a method called "time compression integration" which "records separated component video, luminance and colorsignals are offset by time in alternating parts of the video track". Because video signals are recorded in component form instead of the color under method used by S-VHS, standard definitionimage quality for W-VHS is typically much higher, due to the lack of noise caused by a chroma sub-carrier. Audio is stored in the VHS Hi-Fi or S-VHS Digital Audio formats. W-VHS VCRs can record a standard or high definition videosignal via an analog Y/Pb/Pr component interface. Very few devices with this capability exist, possibly due to content copyright restrictions. W-VHS has also been used for medical imaging, professional previewing, and broadcasting. Due to its high cost, W-VHS equipment and media was distributed in the United States through JVC's professional video and broadcast equipment division and was primarily marketed for industrial and commercial applications such as medical imaging. Currently, it is very difficult to find either W-VHS VCRs or tapes. Because of this scarcity, users have turned to the similar Digital-S tape which uses the same kind of metal particle coating. While D-9 tapes are still not that easy to find, they are more available than W-VHS tapes in certain regions. JVC Professional even recommends the use of them for W-VHS. The running time between W-VHS and Digital-S is not the same; a Digital-S tape with a length of 64 min is approximately 105 min when used with W-VHS.
