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The
VP4\S
has
a
built-in
video
miler
which is able 10
mil
either the
RGB
signal
derived from
tbe video
disc
(via
the PAL-RGB decoder)
or an
RGB
signal derived from an
eltem
al
video signal (conncclCd lo
one of
1hc
CVBS
IN
soc:kels),
with
an eltcmal
Tn
ROB
signal
from
the RGB (TTL) IN
soc:kCI
This facility allows the
TIL RGB graphics ou1pu1
of
an ex1cmal
compu1er
to be milcd
wi1h
1hc
off-disc video
(or
exiemal
video) in
a
number
of
ways.
The miled
Vkico is
avai lab
le
at
the
Euroconncctor
soc:ke1:
Mo*I:
PlayerRGBon
ly
Model:
Compu1erRGBonly
Model:
Keymode
Playcroutput
:
100'J'.intensity
Computeroutp.it:
100%
intensity
Mode<I:
Mixcdmode(nansparentvaphics)
Playt:roulput:
02%
intensily
Computeroulp.11:
38%
inlensily
Mode5:
Enhanccdvideo
•'highlighting'
(presence
of
graphics
produces
IOO%
intensityvideoatlhatpoinl;
elsewhere
video
is reduced)
Playeroutput(
inpresenceofgraphics):
IOO¾intensity
Player
output
(No
graphics):
57%intensity
When mixing in
1his
manner. the VP4\S
'genlocks"
to the
oomposilC
sy
ncsignalfromthe extemalcompu1er.
·--
The
VP415
;;i.lso incorporates
an
'
Instant Jump'
feature.
Essen1ially
this
means
th at
the
radial mirror
which points
the
laser
beam at
the required
disc
u
ack
can be
made 10 ·twitch'
and therefore
jump
a
predetermined
number
of
!racks
(max.
SO)
in
either direction
during
the vertical
internl (field nyback
1ime).
Small
jumps
are
invisible,
as they can be
performed within
the
video
blanking.
This
gives
the
effect of
an
instant
search
to the required
picture
· almost as
if
it were
immediately
adjacentlothecurrentpicture.
This feature is
valuable
in
for
example
map-walking.
where
each
picture
contains
a
map
of an
area
and each successive picture shOW5
adjacent
areas.
The
user can
'scan· across map boundaries
with no
'
black picture' between maps
while
the
playe
rsearchesforthenext
picture.
It
is also possible
to
in1er\eave programmes on the
disc
such
that by
playing th
e
disc
and
missins
ou1 (jumping over)
every altem
ate
picture,
one particular storyline is followed, and
then by
offseuing
this
proces.s
by one
picture,
another
storyline is immedia1ely
accessed
and
followed
.
II musl be
realised
1ha1
foUowiog a
jump, the
opttelll slide
requires
a
finite time 10
·catch
up·
artd centralise
lhe radial miC"Tor. Thus
a
limit is
imposed
on
how man
y
jumps may
be
made
in a
given lime. The limit
OCCUB
when the
effective
playing
speed of
the disc exceeds 20
times
normal speed, i.e. ii
is
possible
to
jump 20
tracks,
display for a
period
of
I
picture, then
jump
another20
tracks
etc. continuously,
without the
optical slide
falling behind
.
Details of the
types
of jump possible,
and their
associated commands
are given
in lhe
F·Code command
list
(sec Section
6).
TbeVP41Sfea1uresaveryfastrandomaettsstime;1hisisthe1ime
needed
for
the
optical
readout unit 10 move from
one point on
the disc
10 another,
which
may
be
anywhere
on
lhe
disc.
Figures
are typically
1
s
for
a
CAV
disc
and
Ss
fora CLV
disc.
Wiredreaoteeoatrol
In
some applications it
may
be
required
lo
hide
lhe
VP41S.
In such
cases,
the infra-red
beam of
the remo1e
control
handsc1
may no1
be
able to operate
.
For reliable working
under such
conditions,
the
wired
connection should be
used
between
the
remote control
handset
and
the
WIRED RCsockct
at
the rear
of
the
player.
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