On 10/11/2007 03:14, Ethan Dicks wrote:
Some videodisc players are designed for interactive
use and
have a parallel or serial input port, but the computer only sends
start/stop/seek commands to the player. The player still squirts
out NTSC (or PAL?) video to a monitor, not digitized frames to
the controlling computer. Those models can typically be controlled
via front-panel buttons even when a computer is not attached.
The Philips ones used in Acorn's Domesday system (1986) are rather like
that. They have an extra SCSI interface, so the computer can control
the player through that, and the player's video is fed to a genlock card
in the computer so the two video stream can be mixed under computer
control, but the laser video isn't digitised. However, some of the
audio tracks actually hold data that the computer *can* read (captions,
indexing, programs, etc).
--
Pete Peter Turnbull
Network Manager
University of York