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W-VHS is a HDTV analog recording videocassette 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. The name refers to common usage of "W" in Japanese to refer to the English word "double". The recording medium of W-VHS is a ½-inch metallic magnetic tape stored in a cartridge the same size as VHS. The tape can be used to store 1035i (HD) or 480i (SD) and a double channel of 480i (for storing 3D programs〔(What is a 3D theater )〕)(SD2) analog signals (but not 480p, 720p or 1080i). The video signal is recorded using a method called "time compression integration" which "records separated component video, luminance and color signals are offset by time in alternating parts of the video track".〔Quote from JVC SR-W5U pdf brochure.〕 Because video signals are recorded in component form instead of the color under method used by S-VHS, standard definition image 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 were one of the only devices consumers could use to record a standard or high definition video signal 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. Currently, it is very difficult to find either W-VHS VCRs or tapes. Since W-VHS tapes are harder to find users have turned to the similar Digital-S (D-9) tape. 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. ==See also== * D-VHS * S-VHS * Blu-ray Disc 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「W-VHS」の詳細全文を読む スポンサード リンク
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