peck@ral.rpi.edu (Joseph Peck) (05/09/91)
I found some time on my hands last week, so I got to thinking about
new video modes for the Amiga. My thoughts ran along these lines:
(Ignoring interlace for a moment...) An NTSC amiga has a
vertical resolution of 200 lines. The agnus in the 3000 can
switch to PAL mode, a change from 60hz to 50hz. This nets us
an improvement to 256 lines. In terms of interlace, we have
400 vs 512 lines....
Why not take this reduction in frequency a step further, and
offer a 30hz/25hz mode. This would provide a 400/512 non-interlaced
signal and a 800/1024 interlaced signal. Now obviously this wouldn't
work on my 1080, but (demonstrating my lack of video display knowledge)
wouldn't this work on a multisync?
Of all the suggestions made so far, this seems like the least
costly to implement. (Then again, everyone with a new idea tends
to think that... :) Does anyone have any idea why this wouldn't
work, or is otherwise infeasible?
The biggest downside is that all of the new games would run at
30/25 fps instead of 60/50 :) :) :) :) :)
Oh yeah, and this would keep Scott Hood busy on a de-interlacer
board with more memory. ;)
Comments, attacks and flames welcome,
Joe Peck
peck@ral.rpi.eduronald@ecl014.UUCP (Ronald van Eijck) (05/11/91)
In article <jq9g78l@rpi.edu> peck@ral.rpi.edu (Joseph Peck) writes: > > I found some time on my hands last week, so I got to thinking about >new video modes for the Amiga. My thoughts ran along these lines: > > Why not take this reduction in frequency a step further, and >offer a 30hz/25hz mode. This would provide a 400/512 non-interlaced >signal and a 800/1024 interlaced signal. Now obviously this wouldn't >work on my 1080, but (demonstrating my lack of video display knowledge) >wouldn't this work on a multisync? > >Comments, attacks and flames welcome, >Joe Peck >peck@ral.rpi.edu I won't flame you, just a reason why it doesn't work. 30/25 hz display have the all famous interlace flickering. This flickering is a lot worse on a 25 hz screen than on a 30hz screen going down the line to 15/12.5 hz will produce pictures that flicker so bad that the upper half of the screen will completely vanish while the videobeam is writing the lower half of the screen. This has everything to do with the speed the eye can see a picture and the time it takes for the fosfor of a monitor to stop gloing. Maybee some more knowledgable person can go into details. -- +-------------------------------------------------------------------------+ | Ronald van Eijck R&R Software | | | | We do the impossible at once for a miracle we need a little more time | +-------------------------------------------------------------------------+
mmm@reaper.Chi.IL.US (Michael Marvin Morrison) (05/14/91)
In article <ronald.3464@ecl014.UUCP> ronald@ecl014.UUCP (Ronald van Eijck) writes: >In article <jq9g78l@rpi.edu> peck@ral.rpi.edu (Joseph Peck) writes: >> >> I found some time on my hands last week, so I got to thinking about >>new video modes for the Amiga. My thoughts ran along these lines: >> >> Why not take this reduction in frequency a step further, and >>offer a 30hz/25hz mode. This would provide a 400/512 non-interlaced >>signal and a 800/1024 interlaced signal. Now obviously this wouldn't >>work on my 1080, but (demonstrating my lack of video display knowledge) >>wouldn't this work on a multisync? >> >>Comments, attacks and flames welcome, >>Joe Peck >>peck@ral.rpi.edu > >I won't flame you, just a reason why it doesn't work. > >30/25 hz display have the all famous interlace flickering. This flickering >is a lot worse on a 25 hz screen than on a 30hz screen going down the line >to 15/12.5 hz will produce pictures that flicker so bad that the upper half >of the screen will completely vanish while the videobeam is writing the >lower half of the screen. This has everything to do with the speed the eye >can see a picture and the time it takes for the fosfor of a monitor to stop >gloing. Maybee some more knowledgable person can go into details. > >-- > +-------------------------------------------------------------------------+ > | Ronald van Eijck R&R Software | > | | > | We do the impossible at once for a miracle we need a little more time | > +-------------------------------------------------------------------------+ The 2024 monitor does something similar to this, as it has 15hz and 10hz display modes. Although it plays some funky games with the signal, as it is sent out something like this: __________________________ | | | | | | | 640x400 | 368x400 | | 1| 2| == 1008x800 |_______________|__________| | | | | | | | 640x400 | 368x400 | | 3| 4| |_______________|__________| And the monitor takes care of putting it back to normal via hardware. The 2024 screens are non-dragable also. It was very sharp (although sorta liquid like) and a 5x7 font looked just fine. Now let's see.. using some kind of "supreme persistance" monitor, we could half this for maybe 1008x1200 (adding another set of screens to the bottom) or maybe 1280x1200 at 1 (hert? :-) using 6 sets of 640x400 screens. But then again, that would only give us a max of ~256x171 text resolution in a shell (using 5x7 font) or a mere 21 80x24 size windows open. :-) -- Michael M Morrison /| |\ mmm@reaper.chi.il.us <or> | | Cash, for Cache.. | | reaper!mmm@miroc.chi.il.us \| Hmm.. sounds fair. |/
peck@ral.rpi.edu (Joseph Peck) (05/14/91)
In article <mmm.1195@reaper.Chi.IL.US> mmm@reaper.Chi.IL.US (Michael Marvin Morrison) writes: >In article <ronald.3464@ecl014.UUCP> ronald@ecl014.UUCP (Ronald van Eijck) writes: >>In article <jq9g78l@rpi.edu> peck@ral.rpi.edu (Joseph Peck) writes: >>> >>> I found some time on my hands last week, so I got to thinking about >>>new video modes for the Amiga. My thoughts ran along these lines: >>> >>> Why not take this reduction in frequency a step further, and >>>offer a 30hz/25hz mode. This would provide a 400/512 non-interlaced >>>signal and a 800/1024 interlaced signal. Now obviously this wouldn't >>>work on my 1080, but (demonstrating my lack of video display knowledge) >>>wouldn't this work on a multisync? [stuff] > >The 2024 monitor does something similar to this, as it has 15hz and 10hz display >modes. Although it plays some funky games with the signal, as it is sent out >something like this: > > __________________________ > | | | > | | | > | 640x400 | 368x400 | > | 1| 2| == 1008x800 > |_______________|__________| > | | | > | | | > | 640x400 | 368x400 | > | 3| 4| > |_______________|__________| > >And the monitor takes care of putting it back to normal via hardware. The 2024 >screens are non-dragable also. It was very sharp (although sorta liquid like) >and a 5x7 font looked just fine. Now let's see.. using some kind of "supreme >persistance" monitor, we could half this for maybe 1008x1200 (adding another >set of screens to the bottom) or maybe 1280x1200 at 1 (hert? :-) using 6 sets of >640x400 screens. But then again, that would only give us a max of ~256x171 text >resolution in a shell (using 5x7 font) or a mere 21 80x24 size windows open. :-) So is the A2024 monitor something made especially for Commodore? Or is there a hardware do-hickey that does all of the interfacing with a standard monitor? If Commodore can have monitors made for them, it seems like my initial idea is a fairly valid method of providing for (whatever) x 800 modes. > >-- >Michael M Morrison /| |\ >mmm@reaper.chi.il.us <or> | | Cash, for Cache.. | | >reaper!mmm@miroc.chi.il.us \| Hmm.. sounds fair. |/ Joe Peck peck@ral.rpi.edu