Digital-S, later known as D-9, is a professional Digital video videocassette format created by JVC in 1995.
It is a direct competitor to Sony's Digital Betacam. Its name was changed to D-9 in 1999 by the SMPTE.[ "D-9 in action worldwide"] but was a commercial failure compared with Digital Betacam. It was superseded by high-definition tapeless formats.
Technical details
The Digital-S tape itself uses a much higher quality metal particle formulation. The recording system is digital and for video uses DV compression at a 50 Mbit/s
bitrate. Video is recorded in
Component video format at a variety of standard-definition resolutions, in either 4:3 or 16:9 aspect ratios. Audio is recorded as 16-bit/48 kHz PCM with up to four separate channels.
[ "D-9 technical specifications" , Displays general D-9 technical specifications. Accessed October 13, 2007.] The tape is 1/2 inch wide, the helical scan head drum is 62 mm in diameter, and the video tracks, which are read by the video heads in the head drum, are 20 microns wide.
Video quality is generally very high; at standard definition, D-9's quality is comparable with Digital Betacam.
[ Professional Japan"] The BR-D51U model is additionally capable of analogue S-VHS playback.
HD recording
For high-definition video recording, JVC developed an extension to D-9 called D-9 HD, using twice the number of recording heads to record a 100 Mbit/s video bitstream at resolutions of 720p60, 1080i60 and 1080p24. This variant can also record 8 channels of PCM audio at 16 bits and 48 kHz. The higher data rate and increased tape speed mean that the recording time of any given cassette would be halved.
[ "D-9 HD Technical Specifications"] D-9 HD, based on specifications, would have been higher quality than Sony
HDCAM but lower than Sony
HDCAM SR; no objective tests were made comparing these formats. It is not clear whether this proposed format was ever manufactured or sold.
Additional information
Although D-9 uses the same video codec as DV, the video bitrate of D-9 is significantly higher than that of the format.
DVCPRO achieves bitrate parity with D-9 and D-9 HD, but has a slower tape speed, making it less reliable. Some of the D-9 television studio gear is capable of recording with
Sel-Sync or pre-read and is provided with four-channel audio like Digital Betacam. Serial digital interfaces (SDI) are also provided. A dockable recorder, the JVC BR-D40, attached to a variety of cameras, and there was a one-piece camcorder, the JVC DY-70U.
