[stella] Closed Captions (Again)

Subject: [stella] Closed Captions (Again)
From: A Braunsdorf <ab@xxxxxxxxxxxxxx>
Date: Wed, 22 Nov 2000 18:25:42 -0500
I thought I was clever coming up with the idea of using closed
captioning on the 2600, but figured I'd search the archives first
to see if I was being stupid. :-)

Looks like you guys stopped where I did last time I thought about
messing with this.  I started reverse-engineering CC for another
project I was doing, but I'm not sure where my notes are (on my
Amiga, probably).

Closed captions are sent two characters to a line as big fat white
bits on a black background.  I don't recall whether it's sixteen
bits or not (something itches in my brain and tells me it's not),
but I can just roll my monitor and look, so I will later on.

Glenn posted the character table from the FAQ.  The lower number
characters are used to position the cursor, flip the pages, scroll
regions, and switch attributes and stuff.  It's not so bad figuring
this stuff out if you have a monitor that lets you see the signal
and a LD player to generate a good clean, repeatable signal you
can vary the speed and direction on.

If we can change the playfield halfway across the screen (or close
enough we can use a player to cover the overlap), I think it'll
work.  You'd just have to spit the two characters out on line 21
and maintain the pace.  If you don't keep changing the line, the
captions go away (which makes it harder to figure out).

I don't have my 2600 development environment set up here yet, but
I'm about a trip to Radio Shack away from it, so maybe I'll try
this later in the week.  I'm trying hard to not do any real work
on my vacation, so this'd be a good project. :-)

Anyone have any great ideas about getting me 16 arbitrary bits or
so across a scan line?  The decoders are pretty tolerant, so
switching the playfield might work (even though 8 doesn't go into
20 nicely) if it was pretty reliable.  Or a combination of really
fat players and playfield graphics maybe?  Give it some thought.

Looks like I ought to at least finish off reverse engineering CC.
No sense in giving those pricks their ransom money.  It'll be easier
if I have a machine that I can use to try generating some.  The
2600 is actually a pretty good choice since most machines won't
let you play up there these days.


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