Re: [stella] What's an acceptable scanline count? (NTSC)

Subject: Re: [stella] What's an acceptable scanline count? (NTSC)
From: "Andrew Davie" <atari2600@xxxxxxxxxxxxx>
Date: Mon, 14 Jul 2003 14:33:45 +1000
That depends on the particular TV and its ability to synchronise to the
resulting refresh rate required.  In other words, it depends on what
threshold (how many TVs your game will work on, and how many it will fail
on) you are willing to accept.  The higher the lines per frame, the lower
the frames per second.  Stick to 262 lines (NTSC) and 312 lines (PAL)  and
Bob's your Uncle.

frame/second x lines/frame x cycles/line = 6502 clock speed

So, frames/second = 6502 clock speed / ( lines/frame x 76 )

With 270 lines you're getting a frame rate of roughly 58 frames/second.  I
imagine most NTSC TVs can cope with this.
With 312 lines (PAL!) you're getting a frame rate of 50 frame/second.  PAL
Tvs like this :)

Cheers
A





----- Original Message ----- 
From: "Zach Matley" <matleyz@xxxxxxxxxxxxxxxxx>
To: <stella@xxxxxxxxxxx>
Sent: Monday, July 14, 2003 2:09 PM
Subject: [stella] What's an acceptable scanline count? (NTSC)


> Hi everyone,
>
> I've noticed that many of the Atari games have 262 or 263 scanlines, and
> some of Thomas' PAL->NTSC conversions are above 270. I'm just wondering
> how high the scanline count can get before problems start.
>
> Thank you,
> Zach
>
>
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