A new technology being developed by JVC that uses VHS tapes to store digital video using MPEG-2 compression. D-VHS stores digital video in three modes - High Speed (HS), standard (STD) mode and Low Speed (LS). HS mode is capable of recording HDTV and multiple channel broadcasts at a data rate of 28.2Mbps for up to 3.5 hours on a single DF-420 cassette (which apparently holds up to 44.4GB of data). STD mode can record up to 7 hours of digital video at a data rate of 14.1Mbps. LS mode can record up to 49 hours of video at four selectable data rates - 2.0Mbps for 49 hours of video, 2.8Mbps for 35 hours, 4.7Mbps for 21 hours and 7.0Mpbs for 14 hours. D-VHS is also capable of bit-stream recording of HDTV broadcasts (meaning that it is recorded digitally without any analog-digital conversion) and is backwards compatible with the large library of existing VHS tapes (it can also record in S-VHS as well as digital).

Advantages:

  • backwards compatible with existing VHS tapes
  • can store up to 49 hours of high quality digital video
  • supports high-definition picture quality (so it can take full advantage of HDTV sets)
  • capacity for HDTV resolutions means that D-VHS releases can be made directly from the studio's 1080i (1920x1080) digital vault masters without resizing and subsequent quality loss

Disadvantages:

  • tape degradation can affect picture quality, although this is less of an issue with a digital format because error correction code can compensate for this
  • still a sequential format (ie. even with chapter stops, the tape must still be wound back and forth)
  • no capacity for special features, although this could be an advantage, depending on how you look at it
  • D-VHS tapes and equipment are relatively expensive (approximately US$40 for tapes and US$2000 for a recorder)
  • copy protection for prerecorded movies (called D-Theater) means you can't copy D-VHS tapes
  • will have difficulty competing with the more entrenched DVD format for home movies (which, by comparison, is non-linear, cheaper and has a larger library of movie titles)

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