Archive for category Live vision systems
D-VHS
Posted by Steve Wylie in Live vision systems, Video and motion graphics on March 22, 2006
Back in 1996, the year that the DVD format was released, JVC finalised the specifications for the D-VHS format – a digital tape format that used MPEG2 to store SD and HD content with many DVD-like features.
With support from Hitachi, Matsushita, and Philips, the D-VHS format boasted the ability to record up to 3.5 hours of High Definition content at a bitrate of 28.2 Mbps or between 7 and 49 hours of Standard Definition content at bitrates ranging from 14.1 Mbps down to 2 Mbps.
D-VHS also supported 5.1 channel and 2 channel PCM audio, and full compatibility with all ATSC broadcasting formats for HDTV support – this was its major advantage over DVD, which is only just waking up to high definition content through HD-DVD and Blu-ray.
The format only supported bitstream recording, which meant that analog-to-digital and digital-to-analog conversion wasn’t native to the standard – however IEEE1394 (commonly known as FireWire) was incorporated as a standard interface for D-VHS and most D-VHS decks included encoders and decoders that permitted analog interfaces.
Backwards compatibility with S-VHS and VHS was a bonus, however the confinement to a linear storage medium (tape) would always be a serious disadvantage as compared to optical, solid state, or hard disk mediums – which support random access so we don’t have to rewind and fast-forward to get to the content that we want to play back.

