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PostPosted: Thu Feb 15, 2018 6:36 am 
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Was it to improve composite picture quality? If it was, they should've had a missing half cycle every frame instead, so that artifacts cancled out entirely.


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PostPosted: Thu Feb 15, 2018 7:31 am 
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To improve it even better, each scanline would have been 341.25 pixels (1365 master clocks) long, with the extra master clock not inserted during each of the three lines of vsync. But that would probably have required more logic (therefore more expensive die area and/or more circuit golf) than what they ended up doing.


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PostPosted: Thu Feb 15, 2018 7:48 am 
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It's definitely there to counter-act composite artifacts, I can't think of any other valid reason.

There's a good thread on the subject here, though it's mostly centered around how to disable the "feature", so I'm not sure if it's able to add anything of value: https://shmups.system11.org/viewtopic.php?f=6&t=61285


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PostPosted: Fri Feb 16, 2018 9:34 am 
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tepples wrote:
To improve it even better, each scanline would have been 341.25 pixels (1365 master clocks) long, with the extra master clock not inserted during each of the three lines of vsync. But that would probably have required more logic (therefore more expensive die area and/or more circuit golf) than what they ended up doing.


Well, I think frame cancellation is more important than line cancellation because you don't lose any information for static screens.


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