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From: rhialto@cs.kun.nl (Olaf'Rhialto'Seibert)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: I got problem with overscan*interlace*PAL
Message-ID: <3622@wn1.sci.kun.nl>
Date: 6 Jun 91 15:51:04 GMT
References: <1991Jun2.183144.22881@daimi.aau.dk> <1991Jun3.135118.944@csc.canterbury.ac.nz> <1991Jun4.175631.20446@daimi.aau.dk>
Sender: root@sci.kun.nl
Organization: University of Nijmegen, The Netherlands
Lines: 24

In article <1991Jun4.175631.20446@daimi.aau.dk> pilgrim@daimi.aau.dk (Jakob G}rdsted) writes:
>>In article <1991Jun2.183144.22881@daimi.aau.dk>, pilgrim@daimi.aau.dk (Jakob G}rdsted) writes:
>>> I use a PAL a500. Both of these programs fail on one type
>>> of pictures. That is, interlaced, 4colour overscan pictures.
>>> It seems like, when one tries this, that the machine acts like
>>> the display is NTSC.

>And that is the only solution? And whose "fault" is it, i.e. is it
>a hardware or software bug, is it OS dependant(= fixed in 2.0) ? or
>what? I'm glad to hear it was not me going mad, it has driven me
>crazy( :-) for the last 2 years.

It is a software fault. Comparing different cases, analyzing the copper
lists that are generated, made this clear. The relevant factors are
1. >= 640+32 (= 672) pixels wide (hires)
2. > 216 lines high (in non-interlace mode)
3. 4 bitplanes
If you drag such a truncated screen below line 216 (if I remember that
number correctly) the area below reappears again.


-- 
Olaf 'Rhialto' Seibert                               rhialto@cs.kun.nl
How can you be so stupid if you're identical to me? -Robert Silverberg