pnm@goanna.cs.rmit.oz.au (Paul BIG-EARS Menon) (05/23/91)
hi,
Does CloseView use "Apple convolution" when magnifying?
I ask this because of some strange results I'm getting
with a Mass MicroSystems ColorSpaceIIi (PAL output) card.
The symptoms are as follows..
PAL output (as is NTSC) is interlaced. So a Mac window being displayed
is very sore on the eyes (the title bar for starters). However, even
using MM Director and ensuring that horizontal lines are of even
pixel thickness (no "Mac" windows visible) doesn't guarantee that
a picture of a horizontal line will not flicker. When displayed in one
position of the screen, it's rock solid. On moving it to another -
wobblies occur. To me, this appears to be a problem with the card.
There is no huge difference in the colour of the background and
the line. I've tried horizontal lines of various even pixel thicknesses,
they all behave the same - unpredictably.
Even more curious - when displaying a "normal" Mac desktop scene with
(say) one window open - we have the wobblies. On using CloseView (even
magnification) - the picture is rock solid - regardless of screen content.
On using CloseView with odd magnification - it flickers, but not as bad
as previously. This makes me suspect some averaging of adjacent pixels.
I'm not saying this is good or bad (to me it's good) - all I want to know
is - what's going on?? I'm really having a hard time getting rid of
flicker from this card. Following the "rules" doesn't seem to help when
the pic behaves differently depending on image position on the screen -
except while using CloseView. Is this just a low level card, or one in
need of adjustment? I note that It's very slow compared to the 8.24GC,
but I guess that should be expected.
I've also noted that the 8.24GC is capable of generating PAL (or NTSC)
signals, and has convolution (averaging) capabilities (see Developer July
'90). Apart from the sense line encoding, I presume I'll need an RGB->PAL
encoder for colour PAL, yes?? No??? If I take the green signal, I presume
I only get a mono PAL picture, yes?? No?? Could someone please confirm.
Has anyone used the 8.24GC in PAL mode? What's it like?
Thanks for any info (please mail a response too)
Paul Menon,
Dept of Computer Science,
Royal Melbourne Institute of Technology,
124 Latrobe Street,
Melbourne 3001,
Victoria, Australia.
pnm@goanna.cs.rmit.oz.au
PH: +61 3 660 3209