brent@well.UUCP (Richard Brent Southard) (06/10/86)
There are a few questions I'd like answered once and for all, if anyone here is knowledgeable on the topic of video signal processing. I understand the fun- damentals involved with the Amiga's interlaced video mode. However, I understand that a standard television uses the same principles for generating its display, and yet there is (normally) no flicker noticeable on a television screen. The only thing I can figure is that a tv uses a longer-persistance phosphur than the standard Amiga monitor (model 1080). This would imply that using composite video output from the Amiga with a television would provide a flicker-free display, although without the clarity of the RGB display. Has anybody tried this? Now here's the interesting part... While conferencing on CompuServe, an Amiga- Forum member mentioned that he had overcome the flicker problem on his 1080 monitor. He said that he'd done this by filtering his video signal through an "Interlaced Signal Filter" (I believe). Now, I don't understand what this filter could do to the signal to make it flicker-free. It seems that the only way around flicker in 640x400 mode on the 1080 would be to draw all 400 lines in one scan (1/60th of a second). On the other hand, if such a device exists, how does it work? What magic massaging is done to the signal? Anybody familiar with this stuff? brent
stever@videovax.UUCP (Steven E. Rice) (06/15/86)
In article <1249@well.UUCP>, Richard Brent Southard (brent@well.UUCP) writes: > There are a few questions I'd like answered once and for all, if anyone here > is knowledgeable on the topic of video signal processing. I understand the > fundamentals involved with the Amiga's interlaced video mode. However, I > understand that a standard television uses the same principles for generating > its display, and yet there is (normally) no flicker noticeable on a > television screen. The only thing I can figure is that a tv uses a > longer-persistance phosphur than the standard Amiga monitor (model 1080). > This would imply that using composite video output from the Amiga with a > television would provide a flicker-free display, although without the > clarity of the RGB display. Has anybody tried this? > > . . . The standard television phosphors are not long-persistence -- this would cause smearing of moving objects. The difference is in the material being displayed. If you put a high-resolution display composed of all capital "E"s up on either an Amiga 1080 monitor or a television set in such a way that the horizontal bars are all written on one field, the flicker will knock your eyes out! For a demonstration of interlace artifacts, look closely at thin, horizontal lines or at the horizontal edges of letters generated by a character generator. They can be pretty awful! Steve Rice ---------------------------------------------------------------------------- {decvax | hplabs | ihnp4 | uw-beaver}!tektronix!videovax!stever