Re: Apple II NTSC emulation

[vladitx <vladitx@nucleusys.com>]

David, Nick is right - IIgs has a totally different approach and it's
composite output is not same as II, IIe and IIc. But it's much much
easier to emulate. ;-)

On Aug 6, 10:00 am, schmidtd <schmi...@my-deja.com> wrote:

> Of course.  My LCD monitor might not be the best testbed for this, but
> I took one more shot - an IIc this time.  It's picture #6 in the
> series.http://www.flickr.com/photos/qsuncle/sets/72157621958347012/

Modern DSP-spoiled LCD monitors do all kinds of filtering/dithering.
Take a look at the man's hat in Aztec. I have a 19" Sony LCD TV which
reduces resolution on composite input with both spatial and temporal
filtering.

I presume we can take the old fully-analog Apple color CRT monitor's
output as reference. If somebody has it and wants to share few
screenshots.

There is at least one composite screenshot on Flickr:
http://www.flickr.com/photos/blakespot/2396577903/sizes/l/in/set-72157604441725927/
But it's DHGR, which I can't compare right now due to still missing
notion of AUX memory in RA2. :-) But all algorithms/tables do handle
DHGR (all processing in 14MHz domain), so we'll be there soon.

I have uploaded few more pictures. Look at Conan's "DATASOFT PRESENTS"
right edge - the border pixels are dim. Also check Gremlins'
"Atarisoft Presents...." - there are green/violet lines connecting
characters, mostly because of very narrow 0.5 MHz Q bandwidth. I
wonder how these look on the "reference" monitor and whether it uses I/
Q demodulation with asymmetric filters or the cheaper U/V demodulation.