The D-VHS Format
D-VHS (Digital VHS) is a format developed and launched by JVC and partners in the mid-1990s. It is actually a remarkable achievement — a fully digital format which offers recording in all approved DTV formats, as well as being backwards-compatible with VHS and S-VHS.
D-VHS uses the same cassette format as standard VHS. It can record and playback both standard definition and high-definition. Digital video is encoded with MPEG-2. High-definition content is recorded at 28.2 Mbit/s. Maximum recording time is 3.5 hours of high definition and up to 49 hours of standard definition.
Ironically the close association between D-VHS and VHS is also it's downfall. Consumers are moving forward and demand is low for formats which are perceived as outdated. The best D-VHS can hope for is to fill a small niche market until VHS is completely dead.
D-Theater is a brand name for distributing pre-recorded D-VHS tapes. D-Theater supports 720p and 1080i resolution and Dolby audio. D-Theater has enjoyed some support from enthusiasts but the future is bleak — it is dead on arrival in the war against other high-definition formats such as Blu-ray and HD DVD.