CompuServe Thread

#DTV World

2 messages in this thread
#37546From: Charles BlaquiereJan 12, 1994 10:37 PM
(This is actually for Lou, and is an addendum to your questions) Lou, my knowledge of the Mac and PC DTV worlds is mostly theoretical, so let me ask you how one of my perceptions holds up: Mac video adapters are more expensive because (a) they need to scan-convert, and (b) they usually feature convolution circuitry which averages each scanline with the next, eliminating interlace flicker at the cost of decreased sharpness. (For example, one would expect the pack of horizontal lines in a Mac's top window title bar to look like a dance club's strobe light on TV; yet, I've seen educational shows where the computer displays come directly from a Mac desktop, and there is no flicker. A lower-cost Amiga genlock, in similar circumstances, would give anyone an epileptic fit) Blaq!
#37575From: Lou WallaceJan 13, 1994 2:11 PM
I suspect your analysis of how the Mac does it is correct – I am pretty sure that is how Video Vision (Radius) works.. The averaging isn't as bad as it would appear because the Mac and PC screens are usually 480 lines (at least), and would be more then NTSC handles effectively, at least as a composite signal. Lou